1342 Original article
Platelet indices and inflammatory markers as diagnostic predictors for ascitic fluid infection Ahmed Abdel-Razika, Waleed Eldarsb and Ehsan Rizkc Background and aim Ascitic fluid infection (AFI) is a common complication in patients with cirrhosis and ascites. Mean platelet volume (MPV) and platelet distribution width (PDW) may be considered as simple and inexpensive indicators of inflammation in some diseases. We aimed to investigate whether platelet size alterations and platelet indices would be useful in predicting AFI in cirrhotic patients. Patients and methods Of 210 patients, only 150 patients with ascites because of cirrhosis and 70 control participants were enrolled in this study. After ascitic fluid analysis, patients were divided into two groups: 84 patients had AFI and 66 patients did not have AFI. MPV, PDW, and inflammatory marker values were determined for all patients. The ability of platelet indices values to predict AFI in cirrhotic patients was analyzed using receiver operating characteristic curve analysis. Results A significant increase in MPV levels was observed in cirrhotic patients with AFI compared with cirrhotic patients without AFI and healthy controls (P < 0.001). A significant increase in MPV, PDW, C-reactive protein, and white blood cell levels was observed in the AFI group compared with the other group (P < 0.001, P = 0.002,
Introduction Liver cirrhosis is the clinical end stage of different entities of chronic liver disease when patients suffer from considerable mortality and morbidity, both of which are correlated positively with disease severity [1]. Ascites are the most common complication, and around 60% of patients with compensated cirrhosis develop ascites within 10 years of disease onset [2]. Spontaneous bacterial peritonitis (SBP) is a major cause of morbidity and mortality in cirrhotic patients with ascites. SBP is estimated to affect 10–30% of cirrhotic patients hospitalized with ascites, and mortality in this group approaches 30% [3]. Many of these patients are asymptomatic, and it is therefore recommended that all patients with ascites undergo paracentesis at the time of admission to confirm the SBP status [4]. Although SBP is less prevalent in an outpatient setting, it is reasonable to also evaluate the ascitic fluid of outpatients because of the high mortality associated with SBP. Platelets are considered an important source of prothrombotic agents associated with inflammatory markers, and play a role in the initiation and propagation of 0954-691X © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins
P < 0.001, and P = 0.001, respectively). The receiver operating characteristic curve for sensitivity and specificity of MPV was assessed. At a cutoff value of 8.77, MPV had 95.9% sensitivity and 91.7% specificity for detecting AFI (area under the curve: 0.964). Conclusion Platelet indices and C-reactive protein are increased in cirrhotic patients with AFI. MPV measurement can be considered an accurate diagnostic test in predicting AFI, possibly because of a continuous systemic inflammatory response. Eur J Gastroenterol Hepatol 26:1342–1347 © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins. European Journal of Gastroenterology & Hepatology 2014, 26:1342–1347 Keywords: ascitic fluid infection, C-reactive protein, liver cirrhosis, mean platelet volume a Tropical Medicine Department, bMedical Microbiology and Immunology Department and cClinical Pathology Department, Faculty of Medicine, Mansoura University, Mansoura, Egypt
Correspondence to Ahmed Abdel-Razik, MD, Tropical Medicine Department, Faculty of Medicine, Mansoura University, 35516, Mansoura, Egypt Tel: + 20 100 790 1009; fax: + 0020507735222; e-mail: [email protected] Received 13 June 2014 Accepted 1 August 2014
vascular and inflammatory diseases [5]. Platelets with large sizes have many granules that can exert their hemostatic and proinflammatory actions with greater efficiency [6]. For these reasons, the mean platelet volume (MPV) and platelet distribution width (PDW) may be considered indicators of platelet function and activation [7]. MPV and PDW are routine tests that are a part of a complete blood count. An increase in MPV has been observed in chronic viral hepatitis because of an increase in the entry of newly produced platelets into circulation, which are larger in volume than the old platelets [8]. The aim of this study was to investigate whether platelet size alterations measured by MPV and PDW with other inflammatory markers would be useful in predicting ascitic fluid infection (AFI).
Patients and methods In this prospective observational study, we recruited consecutive 210 patients with ascites referred for paracentesis to Tropical Medicine Department, Mansoura University from April 2013 to March 2014. All patients DOI: 10.1097/MEG.0000000000000202
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Platelet indices in ascitic fluid infection Abdel-Razik et al. 1343
were subjected to the following evaluations: complete assessment of history taking and physical examination, abdominal ultrasound, laboratory assessment, and ascitic fluid analysis [white blood cells (WBCs), protein, bacteriologic culture with sensitivity, and pathological assessment]. Paracentesis of ascitic fluid was performed for every patient with cirrhosis and ascites who was admitted to our department, independent of the clinical suspicion of AFI, as a routine procedure. The diagnosis of AFI was made on the basis of the presence of at least 250 cells/ml polymorphonuclear leukocyte (PMN) in the ascitic fluid, with or without positive ascitic fluid culture in the absence of hemorrhagic ascites and secondary peritonitis.
(2) Complete blood picture was assessed using the CELL-DYN Emerald cell counter (Abbott, Wiesbaden, Germany). (3) Serum CRP was determined using the latex agglutination test kit (AVITEX CRP Ref OD073/OD023/ OD023/E; Omega Diagnostics Ltd, Alva, Scotland, UK) [9].
Exclusion criteria included patients who were immunocompromised and patients who had received antibiotics before hospital admission. Moreover, patients with heart failure, diabetes mellitus, hypertension, hyperlipidemia, peripheral vascular disease, hematological disorders, and neoplastic disorders and patients with clinically overt hypothyroidism or hyperthyroidism or with clinically and laboratory-evident autoimmune diseases were also excluded from this study. None of the study participants had received anticoagulant medications, NSAIDs, or oral contraceptive drugs before hospital admission.
Statistical analysis
In addition, the control group included 70 healthy agematched and sex-matched individuals (male/female = 31 /39). None of them had diabetes mellitus, hypertension, hyperlipidemia, autoimmune diseases, collagen diseases, or any other comorbid diseases.
Sampling
(1) Blood (5 ml) was withdrawn by venipuncture; 1 ml was stored in an EDTA tube for complete blood count, and 4 ml was stored in a plastic tube and allowed to clot. Nonhemolyzed sera were separated by centrifugation and used for the determination of creatinine, uric acid, C-reactive protein (CRP), and liver functions (alanine aminotransferase, aspartate aminotransferase, total bilirubin, and albumin). (2) An ascitic fluid sample was obtained by paracentesis performed under aseptic conditions from a puncture site in the left or the right lower quadrant with the patient in the supine position. All samples for diagnostic testing were immediately collected at the bedside and processed by laboratory personnel without further delay.
Methodology
(1) Blood glucose, liver profile, and creatinine concentrations were measured on a Dimension Xpand plus chemistry analyzer (Roche Diagnostics, Basel, Switzerland) using commercially available reagents and an enzyme-based kit.
This study was approved by the Ethical Committee of Mansoura University and all patients provided written informed consent before participation in any protocolspecific procedure. The study was carried out in accordance with the guidelines of the Helsinki Declaration.
All statistical analyses were carried out using the SPSS version 17.0 software (SPSS Inc., Chicago, Illinois, USA). Data were first tested by the Kolmogorov–Smirnov test for the distribution of data. Parametric data were expressed as mean and SD. The mean and SD of the differences and the limits of agreement, defined as the mean ± 2 SD of the difference (95% confidence interval), were calculated. An unpaired ttest was used for intergroup comparisons. A P-value of less than 0.05 indicated statistical significance. All hypothesis testing was two-tailed. Analysis of the receiver operating characteristics (ROC) and calculation of the area under the curve (AUC) were used to evaluate MPV, PDW, CRP, and WBC with maximum sensitivity and specificity for differentiation between ascitic patients with AFI and others without AFI. Spearman’s correlation analysis was carried out between MPV levels and other inflammatory markers.
Results Patients’ characteristics
Of 210 consecutive patients, only 150 patients with ascites were included in this study. Approximately after 3 weeks of admission of each case, the final diagnosis of SBP and the etiology of ascites were assessed. According to ascitic fluid analysis and clinical data, patients were divided into an SBP group including 84 patients (50 men and 34 women) and a non-SBP group of 66 patients (28 men and 38 women). A total of 25 patients had malignant ascites (which included 10 patients with leaking hepatocellular carcinoma, four patients with ovarian cancer, four patients with lymphomas, one patient with breast cancer, one patient with stomach cancer, three patients with colorectal cancer, and two patients with pancreatic cancer); in addition, 35 patients had received antibiotics before hospital admission and were excluded from this study. Patients had liver cirrhosis of different etiologies (Table 1). In all, 109 (72.7%) patients had chronic hepatitis C-related cirrhosis, 33 (22%) patients had chronic hepatitis B-related cirrhosis, four (2.7%) patients had autoimmune-related cirrhosis, three (2%) patients had nonalcoholic steatohepatitisrelated cirrhosis, and one (0.6%) patient had cryptogenic cirrhosis (Table 1).
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Table 1
European Journal of Gastroenterology & Hepatology 2014, Vol 26 No 12
Baseline characteristics of patients with liver cirrhosis Number of patients (n = 150) [n (%)]
Parameters Etiology of liver cirrhosis Chronic hepatitis C Chronic hepatitis B Autoimmune hepatitis Nonalcoholic steatohepatitis Cryptogenic Child–Turcotte–Pugh class Child A Child B Child C MELD score
109 33 4 3 1
(72.7) (22) (2.7) (2) (0.6)
In this study, the expected normal ranges of MPV were 6.5–11.5 fl, PDW, 10–18 fl, CRP, up to 5 mg/dl, and WBCs, (4–11) × 103/cmm.
0 98 (65.3) 52 (34.7) 11.2 (10.5–17)
Receiver operating characteristics curve analysis of platelets indices and other inflammatory markers
MELD, model for end-stage liver disease.
According to the Child–Turcotte–Pugh score, 98 (65.3%) patients were classified as stage B and 52 (34.7%) patients were classified as stage C. Model for end-stage liver disease scoring of the studied groups ranged from 10.5 to 17 (Table 1). Fever was the most common presentation, found in 59 (70.2%) patients, followed by abdominal pain in 48 (57.1%) patients, abdominal tenderness in 38 (45.2%) patients, altered mental status in 25 (29.8%) patients, and upper gastrointestinal tract bleeding in 20 (23.8%) patients, whereas 25 (29.8%) patients were asymptomatic. Laboratory and ascitic fluid cell count
There was no significant difference in age and sex between patients compared with the control group. There was a significant increase in bilirubin, MPV, and PDW in patients with ascites versus the control group (1.82 ± 0.81 vs. 0.87 ± 0.48; 8.37 ± 0.98 vs. 7.88 ± 0.47; and 16.8 ± 1.1 vs. 15.2 ± 1.9, respectively). There was a significant decrease in hemoglobin and platelets in patients with ascites versus the control group (9.09 ± 0.69 vs. 13.4 ± 1.05 and 105 ± 35 vs. 230 ± 45). There was no correlation between WBCs in the patient and the control group (5.7 ± 1.35 vs. 6.1 ± 0.9) (Table 2). In addition, there was a significant increase in MPV, PDW, CRP, WBCs, and ascitic fluid WBCs and protein
ROC curve for the sensitivity and specificity of MPV: At a cutoff value of 8.77 fl, MPV had 95.9% sensitivity and 91.7% specificity for detecting SBP [AUC = 0.964 with negative predictive value (NPV) and positive predictive value (PPV) for MPV of 97.5 and 68.6%, respectively] (Table 4 and Fig. 1). ROC curve for the sensitivity and specificity of PDW: At a cutoff value of 17.8 fl, PDW had 73.4% sensitivity and 60.9% specificity for detecting SBP (AUC = 0.605 with NPV and PPV for PDW of 73.5 and 54.3%, respectively). ROC curve for sensitivity and specificity of CRP: At a cutoff value of 10.5 mg/dl, CRP had 85.7% sensitivity and 77.4% specificity for detecting SBP (AUC = 0.765 with NPV and PPV for CRP of 80.7 and 50%, respectively). ROC curve for sensitivity and specificity of WBC: At a cutoff value of 6650/cmm, WBC had 64.3% sensitivity and 50% specificity for detecting SBP (AUC = 0.561 with NPV and PPV for WBC of 71.4 and 42.6%, respectively).
Correlation between mean platelet volume and other inflammatory markers
Spearman correlation analysis showed that there was a significant correlation between MPV and PDW, CRP, WBC, ascitic fluid WBCs, and ascitic fluid protein content (r = 0.61, P = 0.045; r = 0.68, P < 0.001; r = 0.59, P = 0.042; r = 0.69, P < 0.001; and r = 0.79, P < 0.001, respectively) (Table 5). Table 3 Comparison of platelet indices and inflammatory markers with ascitic fluid contents in patients with and without spontaneous bacterial peritonitis
Table 2 Demographic and laboratory parameters of the studied groups
Age (years) Sex (F/M) Hemoglobin (g/dl) WBCs (103/cmm) Platelets (103/cmm) Bilirubin (mg/dl) MPV (fl) PDW (fl)
content in the SBP group versus the non-SBP group (8.98 ± 0.9 vs. 8.04 ± 0.86; 16.8 ± 1.3 vs. 15.3 ± 1.1; 62.4 ± 28.39 vs. 9.81 ± 8.98; 10.16 ± 2.88 vs. 6.99 ± 1.78; 295 ± 45.55 vs. 65.13 ± 35.6; and 210 ± 25.23 vs. 90.5 ± 10.1, respectively) (Table 3).
Patients with ascites (n = 150)
Control group (n = 70)
P-value
55.1 ± 12.2 72/78 9.09 ± 0.69 6.7 ± 1.35 105 ± 35
52.6 ± 11.9 31/39 13.4 ± 1.05 7.1 ± 0.9 230 ± 45
NS NS < 0.001 NS < 0.001
1.82 ± 0.81 8.37 ± 0.98 16.8 ± 1.1
0.87 ± 0.48 7.88 ± 0.47 15.2 ± 1.9
0.02 < 0.001 0.023
MPV, mean platelet volume; PDW, platelet distribution width; WBC, white blood cell.
MPV (fl) PDW (fl) CRP (mg/dl) WBCs (103/cmm) Ascitic fluid analysis WBCs (cells/ cmm) Protein (mg/dl)
Ascites with SBP (n = 84)
Ascites without SBP (n = 66)
P-value
8.98 ± 0.9 16.8 ± 1.3 62.4 ± 28.39 10.16 ± 2.88
8.04 ± 0.86 15.3 ± 1.1 9.81 ± 8.98 6.99 ± 1.78
< 0.001 P = 002 < 0.001 < 0.001
295 ± 45.55
65.13 ± 35.6
< 0.001
210 ± 25.23
90.5 ± 10.1
< 0.001
CRP, C-reactive protein; MPV, mean platelet volume; PDW, platelet distribution width; SBP, spontaneous bacterial peritonitis; WBC, white blood cell.
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Platelet indices in ascitic fluid infection Abdel-Razik et al. 1345
Receiver operating characteristic curve analysis of platelet indices and inflammatory markers to differentiate patients with and without spontaneous bacterial peritonitis
Table 4
MPV (cutoff: 8.77) PDW (cutoff: 17.30) CRP (cutoff: 10.5) WBCs (cutoff: 6650)
AUC
SE
Sensitivity (%)
Specificity (%)
NPV (%)
PPV (%)
0.964 0.605 0.765 0.561
0.030 0.111 0.096 0.112
95.9 73.4 85.7 64.3
91.7 60.9 77.4 50
97.5 73.5 80.7 71.4
68.6 54.3 50 42.6
AUC, area under the curve; CRP, C-reactive protein; MPV, mean platelet volume; NPV, negative predictive value; PDW, platelet distribution width; PPV, positive predictive value; WBC, white blood cell.
Fig. 1
1.0
Sensitivity
0.8 0.6 MPV
0.4
CRP WBC
0.2
PDW 0.0 0.0
0.2
0.4 0.6 1−specificity
0.8
1.0
Receiver operating characteristic curves of platelet indices and other inflammation markers in detecting ascitic fluid infection in cirrhotic patients. CRP, C-reactive protein; MPV, mean platelet volume; PDW, platelet distribution width; WBC, white blood cell.
Correlation between mean platelet volume and other inflammatory markers in patients with spontaneous bacterial peritonitis
Table 5
MPV Characteristics PDW CRP WBCs Ascitic fluid WBCs Ascitic fluid protein content
r
P-value
0.61 0.68 0.59 0.69 0.79
0.045 < 0.001 0.042 < 0.001 < 0.001
CRP, C-reactive protein; MPV, mean platelet volume; PDW, platelet distribution width; WBC, white blood cell.
Discussion Ascites are commonly found in patients with liver cirrhosis and may promote bacterial translocation, increasing the risk of SBP [3]. SBP in outpatients is rare, but when it occurs, it often requires hospitalization to manage the disease [4]. SBP is a major cause of morbidity and mortality in cirrhotic patients with ascites. The diagnosis of SBP is made on the basis of the PMN leukocyte cell count exceeding 250/μl in ascitic fluid; however, this procedure is time consuming and subjective.
SBP is considered to result from a combination of factors inherent in cirrhosis and ascites, such as prolonged bacteremia secondary to compromised host defenses, intrahepatic shunting of colonized blood, and defective bactericidal activity within the ascitic fluid [10]. In addition, transmucosal migration of bacteria from the gut to the ascitic fluid is no longer considered to play a major role in the etiology of SBP [11]. With respect to compromised host defenses, patients with severe acute or chronic liver disease are often deficient in complement and may also have malfunctioning of the neutrophilic and reticuloendothelial systems [12]. Thus, prolonged bacteremia is a potential result of these defects in host defenses. The MPV describes the average platelet size reported in femtoliters and is available on most hematology analyzers. The PDW is a measure of the heterogeneity in platelet size either defined as the distribution width at a 20% frequency level or calculated as the SD of platelet volume divided by MPV × 100 [13]. MPV may be considered a marker of inflammation, disease activity, and efficacy of anti-inflammatory treatment in several chronic inflammatory disorders. It would appear that the size of circulating platelets is dependent on the intensity of systemic inflammation, with contrasting features of MPV in high-grade and low-grade inflammatory disorders and during the course of anti-inflammatory treatment. Platelet count estimations further complicate the interpretation of MPV values in thrombocytopenia [14]. Alternative methods using leukocyte esterase reagent strips, pH testing, and lactoferrin in ascitic fluid are also considered to be useful in the diagnosis of SBP [15]. Moreover, there are new methods for the detection of calprotectin measurement in ascitic fluid [16] and also procalcitonin in serum and ascitic fluid [17]. Therefore, an accurate and convenient method of a rapid diagnosis of SBP remains an unmet clinical need. Although several new markers have also been proposed for the detection of systemic inflammation in patients with AFI, the role of platelets as a marker of systemic inflammation is still not clearly understood. In this respect, the primary goal of our study was to evaluate platelet number and size alterations in cirrhotic patients
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European Journal of Gastroenterology & Hepatology 2014, Vol 26 No 12
with or without AFI in correlation with other inflammation markers and clinical severity indices. In this study, MPV was significantly increased in cirrhotic patients with SBP compared with cirrhotic patients without SBP and the control group (P < 0.001). The ROC curve for sensitivity and specificity of MPV for detection of AFI was found to be comparable with CRP and PDW and superior to WBCs. This is in accordance with Suvak et al. [18], who reported that MPV is increased in cirrhotic patients with AFI. MPV measurement can considered an accurate diagnostic test in predicting AFI, possibly because of an ongoing systemic inflammatory response. This finding may be because platelet activation is a link in the pathophysiology of diseases prone to vascular injury and inflammation. Numerous platelet markers, including MPV, which is a reflection of both proinflammatory and prothrombotic conditions, thrombopoietin, and numerous inflammatory cytokines [e.g. interleukin (IL)-1, IL-6, and tumor necrosis factor-α] regulate thrombopoiesis. The intensity of systemic inflammation can be considered a distinctive factor for classifying conditions associated with large-sized and small-sized circulating platelets. Larger platelets are enzymatically more active than small platelets, produce more thromboxane A2, and inflammatory cytokines have an increased propensity to thrombosis and inflammation [19]. In cirrhotic patients, variable platelet sizes, breakdown of platelets in the spleen, and the increase in IL-6 levels because of inflammation in chronic liver disease are believed to be associated with an increase in platelet production in the bone marrow [20]. As expected, the increased entry of platelets into the bloodstream will not only increase MPV but also lead to an increase of the PDW because of the presence of platelets of various sizes in the blood. As the fluctuating course of MPV in different diseases according to the degree of inflammation as in high-grade inflammatory conditions (e.g. active inflammatory bowel disease, rheumatoid arthritis, or attacks of familial Mediterranean fever) is associated with the circulation of predominantly small platelets, the same disorders at remission and controlled by antiinflammatory drugs are associated with large circulating platelets that subsequently affect the MPV values [14]. Moreover, AFI in cirrhotic patients commonly results in a systemic inflammatory response in the presence of platelets of various sizes in the blood that may affect the MPV values. MPV might be useful in the diagnosis of patients with AFI earlier in the course of disease progression. In our work, a significant increase in MPV levels in cirrhotic patients with AFI was observed. It was reported that at a cutoff value of 8.77 fl, MPV had 91.7% specificity and 95.9% sensitivity for detecting SBP. Moreover, a positive correlation between MPV and other systemic inflammatory markers supported our initial hypothesis
that MPV could reflect ongoing systemic inflammatory responses in cirrhotic patients with AFI. According to this finding, it is hypothesized that MPV not only represents platelet activation and function but also systemic inflammation and infection through cascades of proinflammatory cytokines release during the course of disease progression. Biomarkers have been gaining recognition as an important tool in the diagnosis of bacterial infection. An ideal biomarker would enable physicians to rapidly and reliably establish the diagnosis of a bacterial infection in different patients. CRP, an acute-phase protein produced by the liver in response to infection, is potentially such a biomarker. CRP in healthy individuals is less than 0.5 mg/l, and when these levels are elevated, it can be useful in establishing the etiology of some infections [21]. CRP is an acute-phase reactant that binds to different substrates. It activates the complements, plays a role in cytokine secretion, and increases the phagocytosis of leukocytes. CRP has been reported to be a reliable predictor of SBP and an index of therapeutic effectiveness in adults [22]. CRP is a more sensitive and accurate reflection of the acute-phase response than the erythrocyte sedimentation rate (ESR). ESR may be normal and CRP may be elevated. CRP returns to normal more quickly than ESR in response to therapy [23]. In this work, there was a significant increase in CRP in the SBP group versus the non-SBP group (P < 0.001), with a significant positive correlation being observed between serum MPV and CRP (r = 0.68, P < 0.001). It was reported that at a cutoff value of 10.5 mg/dl, CRP had 77.4% specificity and 85.7% sensitivity for detecting SBP. Preto-Zamperlini et al. [22] reported that the SBP group showed significantly elevated CRP levels, leading to the conclusion that CRP was an independent variable in the prediction of SBP. In a study by Yildirim et al. [24] it was found that CRP was increased in the serum and ascitic fluid of SBP patients. In the present study, PDW was statistically significant in cirrhotic patients with AFI than in those without infection (P =002). It was reported that at a cutoff value of 17.8 fl, PDW had 60.9% specificity and 73.4% sensitivity for detecting SBP. This may be because PDW is a measure of the variation of red blood cells, which can be an indicator of platelet activation, and may thus be related to inflammatory processes during the development of AFI. However, this finding was not supported by Suvak et al. [18], who reported no significant changes in PDW in cirrhotic patients with AFI than in those without infection. This prospective study evaluated the diagnostic utility of measuring MPV, PDW, and CRP in patients with ascites to identify ascitic PMN counts greater than 250/μl in patients referred for paracentesis, and provides the following new information: patients with an elevated PMN
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Platelet indices in ascitic fluid infection Abdel-Razik et al. 1347
count (>250/μl) had higher MPV, PDW, and CRP than those with normal cell counts; this finding indicates that MPV, PDW, and CRP levels correlate well and reliably with the PMN count. It is clinically significant that MPV, PDW, and CRP values in patients with ascites can identify elevated PMN counts. Indeed, MPV, PDW, and CRP may serve as surrogate markers for the PMN count and would be amenable to routine SBP screening, especially when measured by a bedside test. There are several limitations to the current study that merit consideration. First, we included all patients with ascites, irrespective of the etiology, and our results cannot be generalized to all patients with liver cirrhosis. Second, our sample size was relatively small and larger studies are needed to evaluate this test in different clinical settings and to establish a reliable cutoff for MPV, PDW, and CRP for optimal identification of PMN counts greater than 250/μl. Conclusion
Platelet indices and CRP are increased in cirrhotic patients with AFI. MPV measurement can considered an accurate diagnostic test in predicting AFI, possibly because of a continuous systemic inflammatory response.
Acknowledgements
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The authors would like to express their sincere gratitude to the patients and staff of the Tropical Medicine Department, and to the laboratory technicians, for their valuable efforts.
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Conflicts of interest
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There are no conflicts of interest.
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Platelet indices and inflammatory markers as diagnostic predictors for ascitic fluid infection Ahmed Abdel-Razika, Waleed Eldarsb and Ehsan Rizkc Background and aim Ascitic fluid infection (AFI) is a common complication in patients with cirrhosis and ascites. Mean platelet volume (MPV) and platelet distribution width (PDW) may be considered as simple and inexpensive indicators of inflammation in some diseases. We aimed to investigate whether platelet size alterations and platelet indices would be useful in predicting AFI in cirrhotic patients. Patients and methods Of 210 patients, only 150 patients with ascites because of cirrhosis and 70 control participants were enrolled in this study. After ascitic fluid analysis, patients were divided into two groups: 84 patients had AFI and 66 patients did not have AFI. MPV, PDW, and inflammatory marker values were determined for all patients. The ability of platelet indices values to predict AFI in cirrhotic patients was analyzed using receiver operating characteristic curve analysis. Results A significant increase in MPV levels was observed in cirrhotic patients with AFI compared with cirrhotic patients without AFI and healthy controls (P < 0.001). A significant increase in MPV, PDW, C-reactive protein, and white blood cell levels was observed in the AFI group compared with the other group (P < 0.001, P = 0.002,
Introduction Liver cirrhosis is the clinical end stage of different entities of chronic liver disease when patients suffer from considerable mortality and morbidity, both of which are correlated positively with disease severity [1]. Ascites are the most common complication, and around 60% of patients with compensated cirrhosis develop ascites within 10 years of disease onset [2]. Spontaneous bacterial peritonitis (SBP) is a major cause of morbidity and mortality in cirrhotic patients with ascites. SBP is estimated to affect 10–30% of cirrhotic patients hospitalized with ascites, and mortality in this group approaches 30% [3]. Many of these patients are asymptomatic, and it is therefore recommended that all patients with ascites undergo paracentesis at the time of admission to confirm the SBP status [4]. Although SBP is less prevalent in an outpatient setting, it is reasonable to also evaluate the ascitic fluid of outpatients because of the high mortality associated with SBP. Platelets are considered an important source of prothrombotic agents associated with inflammatory markers, and play a role in the initiation and propagation of 0954-691X © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins
P < 0.001, and P = 0.001, respectively). The receiver operating characteristic curve for sensitivity and specificity of MPV was assessed. At a cutoff value of 8.77, MPV had 95.9% sensitivity and 91.7% specificity for detecting AFI (area under the curve: 0.964). Conclusion Platelet indices and C-reactive protein are increased in cirrhotic patients with AFI. MPV measurement can be considered an accurate diagnostic test in predicting AFI, possibly because of a continuous systemic inflammatory response. Eur J Gastroenterol Hepatol 26:1342–1347 © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins. European Journal of Gastroenterology & Hepatology 2014, 26:1342–1347 Keywords: ascitic fluid infection, C-reactive protein, liver cirrhosis, mean platelet volume a Tropical Medicine Department, bMedical Microbiology and Immunology Department and cClinical Pathology Department, Faculty of Medicine, Mansoura University, Mansoura, Egypt
Correspondence to Ahmed Abdel-Razik, MD, Tropical Medicine Department, Faculty of Medicine, Mansoura University, 35516, Mansoura, Egypt Tel: + 20 100 790 1009; fax: + 0020507735222; e-mail: [email protected] Received 13 June 2014 Accepted 1 August 2014
vascular and inflammatory diseases [5]. Platelets with large sizes have many granules that can exert their hemostatic and proinflammatory actions with greater efficiency [6]. For these reasons, the mean platelet volume (MPV) and platelet distribution width (PDW) may be considered indicators of platelet function and activation [7]. MPV and PDW are routine tests that are a part of a complete blood count. An increase in MPV has been observed in chronic viral hepatitis because of an increase in the entry of newly produced platelets into circulation, which are larger in volume than the old platelets [8]. The aim of this study was to investigate whether platelet size alterations measured by MPV and PDW with other inflammatory markers would be useful in predicting ascitic fluid infection (AFI).
Patients and methods In this prospective observational study, we recruited consecutive 210 patients with ascites referred for paracentesis to Tropical Medicine Department, Mansoura University from April 2013 to March 2014. All patients DOI: 10.1097/MEG.0000000000000202
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Platelet indices in ascitic fluid infection Abdel-Razik et al. 1343
were subjected to the following evaluations: complete assessment of history taking and physical examination, abdominal ultrasound, laboratory assessment, and ascitic fluid analysis [white blood cells (WBCs), protein, bacteriologic culture with sensitivity, and pathological assessment]. Paracentesis of ascitic fluid was performed for every patient with cirrhosis and ascites who was admitted to our department, independent of the clinical suspicion of AFI, as a routine procedure. The diagnosis of AFI was made on the basis of the presence of at least 250 cells/ml polymorphonuclear leukocyte (PMN) in the ascitic fluid, with or without positive ascitic fluid culture in the absence of hemorrhagic ascites and secondary peritonitis.
(2) Complete blood picture was assessed using the CELL-DYN Emerald cell counter (Abbott, Wiesbaden, Germany). (3) Serum CRP was determined using the latex agglutination test kit (AVITEX CRP Ref OD073/OD023/ OD023/E; Omega Diagnostics Ltd, Alva, Scotland, UK) [9].
Exclusion criteria included patients who were immunocompromised and patients who had received antibiotics before hospital admission. Moreover, patients with heart failure, diabetes mellitus, hypertension, hyperlipidemia, peripheral vascular disease, hematological disorders, and neoplastic disorders and patients with clinically overt hypothyroidism or hyperthyroidism or with clinically and laboratory-evident autoimmune diseases were also excluded from this study. None of the study participants had received anticoagulant medications, NSAIDs, or oral contraceptive drugs before hospital admission.
Statistical analysis
In addition, the control group included 70 healthy agematched and sex-matched individuals (male/female = 31 /39). None of them had diabetes mellitus, hypertension, hyperlipidemia, autoimmune diseases, collagen diseases, or any other comorbid diseases.
Sampling
(1) Blood (5 ml) was withdrawn by venipuncture; 1 ml was stored in an EDTA tube for complete blood count, and 4 ml was stored in a plastic tube and allowed to clot. Nonhemolyzed sera were separated by centrifugation and used for the determination of creatinine, uric acid, C-reactive protein (CRP), and liver functions (alanine aminotransferase, aspartate aminotransferase, total bilirubin, and albumin). (2) An ascitic fluid sample was obtained by paracentesis performed under aseptic conditions from a puncture site in the left or the right lower quadrant with the patient in the supine position. All samples for diagnostic testing were immediately collected at the bedside and processed by laboratory personnel without further delay.
Methodology
(1) Blood glucose, liver profile, and creatinine concentrations were measured on a Dimension Xpand plus chemistry analyzer (Roche Diagnostics, Basel, Switzerland) using commercially available reagents and an enzyme-based kit.
This study was approved by the Ethical Committee of Mansoura University and all patients provided written informed consent before participation in any protocolspecific procedure. The study was carried out in accordance with the guidelines of the Helsinki Declaration.
All statistical analyses were carried out using the SPSS version 17.0 software (SPSS Inc., Chicago, Illinois, USA). Data were first tested by the Kolmogorov–Smirnov test for the distribution of data. Parametric data were expressed as mean and SD. The mean and SD of the differences and the limits of agreement, defined as the mean ± 2 SD of the difference (95% confidence interval), were calculated. An unpaired ttest was used for intergroup comparisons. A P-value of less than 0.05 indicated statistical significance. All hypothesis testing was two-tailed. Analysis of the receiver operating characteristics (ROC) and calculation of the area under the curve (AUC) were used to evaluate MPV, PDW, CRP, and WBC with maximum sensitivity and specificity for differentiation between ascitic patients with AFI and others without AFI. Spearman’s correlation analysis was carried out between MPV levels and other inflammatory markers.
Results Patients’ characteristics
Of 210 consecutive patients, only 150 patients with ascites were included in this study. Approximately after 3 weeks of admission of each case, the final diagnosis of SBP and the etiology of ascites were assessed. According to ascitic fluid analysis and clinical data, patients were divided into an SBP group including 84 patients (50 men and 34 women) and a non-SBP group of 66 patients (28 men and 38 women). A total of 25 patients had malignant ascites (which included 10 patients with leaking hepatocellular carcinoma, four patients with ovarian cancer, four patients with lymphomas, one patient with breast cancer, one patient with stomach cancer, three patients with colorectal cancer, and two patients with pancreatic cancer); in addition, 35 patients had received antibiotics before hospital admission and were excluded from this study. Patients had liver cirrhosis of different etiologies (Table 1). In all, 109 (72.7%) patients had chronic hepatitis C-related cirrhosis, 33 (22%) patients had chronic hepatitis B-related cirrhosis, four (2.7%) patients had autoimmune-related cirrhosis, three (2%) patients had nonalcoholic steatohepatitisrelated cirrhosis, and one (0.6%) patient had cryptogenic cirrhosis (Table 1).
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Table 1
European Journal of Gastroenterology & Hepatology 2014, Vol 26 No 12
Baseline characteristics of patients with liver cirrhosis Number of patients (n = 150) [n (%)]
Parameters Etiology of liver cirrhosis Chronic hepatitis C Chronic hepatitis B Autoimmune hepatitis Nonalcoholic steatohepatitis Cryptogenic Child–Turcotte–Pugh class Child A Child B Child C MELD score
109 33 4 3 1
(72.7) (22) (2.7) (2) (0.6)
In this study, the expected normal ranges of MPV were 6.5–11.5 fl, PDW, 10–18 fl, CRP, up to 5 mg/dl, and WBCs, (4–11) × 103/cmm.
0 98 (65.3) 52 (34.7) 11.2 (10.5–17)
Receiver operating characteristics curve analysis of platelets indices and other inflammatory markers
MELD, model for end-stage liver disease.
According to the Child–Turcotte–Pugh score, 98 (65.3%) patients were classified as stage B and 52 (34.7%) patients were classified as stage C. Model for end-stage liver disease scoring of the studied groups ranged from 10.5 to 17 (Table 1). Fever was the most common presentation, found in 59 (70.2%) patients, followed by abdominal pain in 48 (57.1%) patients, abdominal tenderness in 38 (45.2%) patients, altered mental status in 25 (29.8%) patients, and upper gastrointestinal tract bleeding in 20 (23.8%) patients, whereas 25 (29.8%) patients were asymptomatic. Laboratory and ascitic fluid cell count
There was no significant difference in age and sex between patients compared with the control group. There was a significant increase in bilirubin, MPV, and PDW in patients with ascites versus the control group (1.82 ± 0.81 vs. 0.87 ± 0.48; 8.37 ± 0.98 vs. 7.88 ± 0.47; and 16.8 ± 1.1 vs. 15.2 ± 1.9, respectively). There was a significant decrease in hemoglobin and platelets in patients with ascites versus the control group (9.09 ± 0.69 vs. 13.4 ± 1.05 and 105 ± 35 vs. 230 ± 45). There was no correlation between WBCs in the patient and the control group (5.7 ± 1.35 vs. 6.1 ± 0.9) (Table 2). In addition, there was a significant increase in MPV, PDW, CRP, WBCs, and ascitic fluid WBCs and protein
ROC curve for the sensitivity and specificity of MPV: At a cutoff value of 8.77 fl, MPV had 95.9% sensitivity and 91.7% specificity for detecting SBP [AUC = 0.964 with negative predictive value (NPV) and positive predictive value (PPV) for MPV of 97.5 and 68.6%, respectively] (Table 4 and Fig. 1). ROC curve for the sensitivity and specificity of PDW: At a cutoff value of 17.8 fl, PDW had 73.4% sensitivity and 60.9% specificity for detecting SBP (AUC = 0.605 with NPV and PPV for PDW of 73.5 and 54.3%, respectively). ROC curve for sensitivity and specificity of CRP: At a cutoff value of 10.5 mg/dl, CRP had 85.7% sensitivity and 77.4% specificity for detecting SBP (AUC = 0.765 with NPV and PPV for CRP of 80.7 and 50%, respectively). ROC curve for sensitivity and specificity of WBC: At a cutoff value of 6650/cmm, WBC had 64.3% sensitivity and 50% specificity for detecting SBP (AUC = 0.561 with NPV and PPV for WBC of 71.4 and 42.6%, respectively).
Correlation between mean platelet volume and other inflammatory markers
Spearman correlation analysis showed that there was a significant correlation between MPV and PDW, CRP, WBC, ascitic fluid WBCs, and ascitic fluid protein content (r = 0.61, P = 0.045; r = 0.68, P < 0.001; r = 0.59, P = 0.042; r = 0.69, P < 0.001; and r = 0.79, P < 0.001, respectively) (Table 5). Table 3 Comparison of platelet indices and inflammatory markers with ascitic fluid contents in patients with and without spontaneous bacterial peritonitis
Table 2 Demographic and laboratory parameters of the studied groups
Age (years) Sex (F/M) Hemoglobin (g/dl) WBCs (103/cmm) Platelets (103/cmm) Bilirubin (mg/dl) MPV (fl) PDW (fl)
content in the SBP group versus the non-SBP group (8.98 ± 0.9 vs. 8.04 ± 0.86; 16.8 ± 1.3 vs. 15.3 ± 1.1; 62.4 ± 28.39 vs. 9.81 ± 8.98; 10.16 ± 2.88 vs. 6.99 ± 1.78; 295 ± 45.55 vs. 65.13 ± 35.6; and 210 ± 25.23 vs. 90.5 ± 10.1, respectively) (Table 3).
Patients with ascites (n = 150)
Control group (n = 70)
P-value
55.1 ± 12.2 72/78 9.09 ± 0.69 6.7 ± 1.35 105 ± 35
52.6 ± 11.9 31/39 13.4 ± 1.05 7.1 ± 0.9 230 ± 45
NS NS < 0.001 NS < 0.001
1.82 ± 0.81 8.37 ± 0.98 16.8 ± 1.1
0.87 ± 0.48 7.88 ± 0.47 15.2 ± 1.9
0.02 < 0.001 0.023
MPV, mean platelet volume; PDW, platelet distribution width; WBC, white blood cell.
MPV (fl) PDW (fl) CRP (mg/dl) WBCs (103/cmm) Ascitic fluid analysis WBCs (cells/ cmm) Protein (mg/dl)
Ascites with SBP (n = 84)
Ascites without SBP (n = 66)
P-value
8.98 ± 0.9 16.8 ± 1.3 62.4 ± 28.39 10.16 ± 2.88
8.04 ± 0.86 15.3 ± 1.1 9.81 ± 8.98 6.99 ± 1.78
< 0.001 P = 002 < 0.001 < 0.001
295 ± 45.55
65.13 ± 35.6
< 0.001
210 ± 25.23
90.5 ± 10.1
< 0.001
CRP, C-reactive protein; MPV, mean platelet volume; PDW, platelet distribution width; SBP, spontaneous bacterial peritonitis; WBC, white blood cell.
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Platelet indices in ascitic fluid infection Abdel-Razik et al. 1345
Receiver operating characteristic curve analysis of platelet indices and inflammatory markers to differentiate patients with and without spontaneous bacterial peritonitis
Table 4
MPV (cutoff: 8.77) PDW (cutoff: 17.30) CRP (cutoff: 10.5) WBCs (cutoff: 6650)
AUC
SE
Sensitivity (%)
Specificity (%)
NPV (%)
PPV (%)
0.964 0.605 0.765 0.561
0.030 0.111 0.096 0.112
95.9 73.4 85.7 64.3
91.7 60.9 77.4 50
97.5 73.5 80.7 71.4
68.6 54.3 50 42.6
AUC, area under the curve; CRP, C-reactive protein; MPV, mean platelet volume; NPV, negative predictive value; PDW, platelet distribution width; PPV, positive predictive value; WBC, white blood cell.
Fig. 1
1.0
Sensitivity
0.8 0.6 MPV
0.4
CRP WBC
0.2
PDW 0.0 0.0
0.2
0.4 0.6 1−specificity
0.8
1.0
Receiver operating characteristic curves of platelet indices and other inflammation markers in detecting ascitic fluid infection in cirrhotic patients. CRP, C-reactive protein; MPV, mean platelet volume; PDW, platelet distribution width; WBC, white blood cell.
Correlation between mean platelet volume and other inflammatory markers in patients with spontaneous bacterial peritonitis
Table 5
MPV Characteristics PDW CRP WBCs Ascitic fluid WBCs Ascitic fluid protein content
r
P-value
0.61 0.68 0.59 0.69 0.79
0.045 < 0.001 0.042 < 0.001 < 0.001
CRP, C-reactive protein; MPV, mean platelet volume; PDW, platelet distribution width; WBC, white blood cell.
Discussion Ascites are commonly found in patients with liver cirrhosis and may promote bacterial translocation, increasing the risk of SBP [3]. SBP in outpatients is rare, but when it occurs, it often requires hospitalization to manage the disease [4]. SBP is a major cause of morbidity and mortality in cirrhotic patients with ascites. The diagnosis of SBP is made on the basis of the PMN leukocyte cell count exceeding 250/μl in ascitic fluid; however, this procedure is time consuming and subjective.
SBP is considered to result from a combination of factors inherent in cirrhosis and ascites, such as prolonged bacteremia secondary to compromised host defenses, intrahepatic shunting of colonized blood, and defective bactericidal activity within the ascitic fluid [10]. In addition, transmucosal migration of bacteria from the gut to the ascitic fluid is no longer considered to play a major role in the etiology of SBP [11]. With respect to compromised host defenses, patients with severe acute or chronic liver disease are often deficient in complement and may also have malfunctioning of the neutrophilic and reticuloendothelial systems [12]. Thus, prolonged bacteremia is a potential result of these defects in host defenses. The MPV describes the average platelet size reported in femtoliters and is available on most hematology analyzers. The PDW is a measure of the heterogeneity in platelet size either defined as the distribution width at a 20% frequency level or calculated as the SD of platelet volume divided by MPV × 100 [13]. MPV may be considered a marker of inflammation, disease activity, and efficacy of anti-inflammatory treatment in several chronic inflammatory disorders. It would appear that the size of circulating platelets is dependent on the intensity of systemic inflammation, with contrasting features of MPV in high-grade and low-grade inflammatory disorders and during the course of anti-inflammatory treatment. Platelet count estimations further complicate the interpretation of MPV values in thrombocytopenia [14]. Alternative methods using leukocyte esterase reagent strips, pH testing, and lactoferrin in ascitic fluid are also considered to be useful in the diagnosis of SBP [15]. Moreover, there are new methods for the detection of calprotectin measurement in ascitic fluid [16] and also procalcitonin in serum and ascitic fluid [17]. Therefore, an accurate and convenient method of a rapid diagnosis of SBP remains an unmet clinical need. Although several new markers have also been proposed for the detection of systemic inflammation in patients with AFI, the role of platelets as a marker of systemic inflammation is still not clearly understood. In this respect, the primary goal of our study was to evaluate platelet number and size alterations in cirrhotic patients
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European Journal of Gastroenterology & Hepatology 2014, Vol 26 No 12
with or without AFI in correlation with other inflammation markers and clinical severity indices. In this study, MPV was significantly increased in cirrhotic patients with SBP compared with cirrhotic patients without SBP and the control group (P < 0.001). The ROC curve for sensitivity and specificity of MPV for detection of AFI was found to be comparable with CRP and PDW and superior to WBCs. This is in accordance with Suvak et al. [18], who reported that MPV is increased in cirrhotic patients with AFI. MPV measurement can considered an accurate diagnostic test in predicting AFI, possibly because of an ongoing systemic inflammatory response. This finding may be because platelet activation is a link in the pathophysiology of diseases prone to vascular injury and inflammation. Numerous platelet markers, including MPV, which is a reflection of both proinflammatory and prothrombotic conditions, thrombopoietin, and numerous inflammatory cytokines [e.g. interleukin (IL)-1, IL-6, and tumor necrosis factor-α] regulate thrombopoiesis. The intensity of systemic inflammation can be considered a distinctive factor for classifying conditions associated with large-sized and small-sized circulating platelets. Larger platelets are enzymatically more active than small platelets, produce more thromboxane A2, and inflammatory cytokines have an increased propensity to thrombosis and inflammation [19]. In cirrhotic patients, variable platelet sizes, breakdown of platelets in the spleen, and the increase in IL-6 levels because of inflammation in chronic liver disease are believed to be associated with an increase in platelet production in the bone marrow [20]. As expected, the increased entry of platelets into the bloodstream will not only increase MPV but also lead to an increase of the PDW because of the presence of platelets of various sizes in the blood. As the fluctuating course of MPV in different diseases according to the degree of inflammation as in high-grade inflammatory conditions (e.g. active inflammatory bowel disease, rheumatoid arthritis, or attacks of familial Mediterranean fever) is associated with the circulation of predominantly small platelets, the same disorders at remission and controlled by antiinflammatory drugs are associated with large circulating platelets that subsequently affect the MPV values [14]. Moreover, AFI in cirrhotic patients commonly results in a systemic inflammatory response in the presence of platelets of various sizes in the blood that may affect the MPV values. MPV might be useful in the diagnosis of patients with AFI earlier in the course of disease progression. In our work, a significant increase in MPV levels in cirrhotic patients with AFI was observed. It was reported that at a cutoff value of 8.77 fl, MPV had 91.7% specificity and 95.9% sensitivity for detecting SBP. Moreover, a positive correlation between MPV and other systemic inflammatory markers supported our initial hypothesis
that MPV could reflect ongoing systemic inflammatory responses in cirrhotic patients with AFI. According to this finding, it is hypothesized that MPV not only represents platelet activation and function but also systemic inflammation and infection through cascades of proinflammatory cytokines release during the course of disease progression. Biomarkers have been gaining recognition as an important tool in the diagnosis of bacterial infection. An ideal biomarker would enable physicians to rapidly and reliably establish the diagnosis of a bacterial infection in different patients. CRP, an acute-phase protein produced by the liver in response to infection, is potentially such a biomarker. CRP in healthy individuals is less than 0.5 mg/l, and when these levels are elevated, it can be useful in establishing the etiology of some infections [21]. CRP is an acute-phase reactant that binds to different substrates. It activates the complements, plays a role in cytokine secretion, and increases the phagocytosis of leukocytes. CRP has been reported to be a reliable predictor of SBP and an index of therapeutic effectiveness in adults [22]. CRP is a more sensitive and accurate reflection of the acute-phase response than the erythrocyte sedimentation rate (ESR). ESR may be normal and CRP may be elevated. CRP returns to normal more quickly than ESR in response to therapy [23]. In this work, there was a significant increase in CRP in the SBP group versus the non-SBP group (P < 0.001), with a significant positive correlation being observed between serum MPV and CRP (r = 0.68, P < 0.001). It was reported that at a cutoff value of 10.5 mg/dl, CRP had 77.4% specificity and 85.7% sensitivity for detecting SBP. Preto-Zamperlini et al. [22] reported that the SBP group showed significantly elevated CRP levels, leading to the conclusion that CRP was an independent variable in the prediction of SBP. In a study by Yildirim et al. [24] it was found that CRP was increased in the serum and ascitic fluid of SBP patients. In the present study, PDW was statistically significant in cirrhotic patients with AFI than in those without infection (P =002). It was reported that at a cutoff value of 17.8 fl, PDW had 60.9% specificity and 73.4% sensitivity for detecting SBP. This may be because PDW is a measure of the variation of red blood cells, which can be an indicator of platelet activation, and may thus be related to inflammatory processes during the development of AFI. However, this finding was not supported by Suvak et al. [18], who reported no significant changes in PDW in cirrhotic patients with AFI than in those without infection. This prospective study evaluated the diagnostic utility of measuring MPV, PDW, and CRP in patients with ascites to identify ascitic PMN counts greater than 250/μl in patients referred for paracentesis, and provides the following new information: patients with an elevated PMN
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Platelet indices in ascitic fluid infection Abdel-Razik et al. 1347
count (>250/μl) had higher MPV, PDW, and CRP than those with normal cell counts; this finding indicates that MPV, PDW, and CRP levels correlate well and reliably with the PMN count. It is clinically significant that MPV, PDW, and CRP values in patients with ascites can identify elevated PMN counts. Indeed, MPV, PDW, and CRP may serve as surrogate markers for the PMN count and would be amenable to routine SBP screening, especially when measured by a bedside test. There are several limitations to the current study that merit consideration. First, we included all patients with ascites, irrespective of the etiology, and our results cannot be generalized to all patients with liver cirrhosis. Second, our sample size was relatively small and larger studies are needed to evaluate this test in different clinical settings and to establish a reliable cutoff for MPV, PDW, and CRP for optimal identification of PMN counts greater than 250/μl. Conclusion
Platelet indices and CRP are increased in cirrhotic patients with AFI. MPV measurement can considered an accurate diagnostic test in predicting AFI, possibly because of a continuous systemic inflammatory response.
Acknowledgements
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The authors would like to express their sincere gratitude to the patients and staff of the Tropical Medicine Department, and to the laboratory technicians, for their valuable efforts.
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Conflicts of interest
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There are no conflicts of interest.
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