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Scandinavian Journal of Clinical and Laboratory Investigation Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/iclb20

Semi-quantitative measurement of myoglobinuria in trauma patients with a latex-agglutination test (Rapi-Tex®) a

b

P. Thorgaard Andersen , P. Jørgen Jørgensen , L. Kjar c

a

Nielsen & J. Sørensen a

Department of Anesthesia, Odense University Hospital, Odense, Denmark b

Department of Clinical Chemistry, Odense University Hospital, Odense, Denmark c

Department of Medicine, Odense University Hospital, Odense, Denmark Published online: 08 Jul 2009.

To cite this article: P. Thorgaard Andersen, P. Jørgen Jørgensen, L. Kjar Nielsen & J. Sørensen (1992) Semi-quantitative measurement of myoglobinuria in trauma patients with a latex-agglutination test (Rapi-Tex®), Scandinavian Journal of Clinical and Laboratory Investigation, 52:8, 847-851 To link to this article: http://dx.doi.org/10.3109/00365519209088390

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Scand J Clin Lab Invest 1992; 52: 847-851

Semi-quantitative measurement of myoglobinuria in trauma patients with a latex-agglutination test ([email protected])

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P . T H O R G A A R D A N D E R S E N , * P. J @ R G E N J B R G E N S E N , ? L. K J E R NIELSENg & J. [email protected]* *Department of Anesthesia, ?Department of Clinical Chemistry, and $Department of Medicine, Odense University Hospital, Odense, Denmark.

Thorgaard Andersen P, Jargen J0rgensen P, Kjaer Nielsen L, S~rensenJ. Semiquantitative measurement of myoglobinuria in trayma patients with a latexagglutination test ([email protected]). Scand J Clin Lab Invest 1992; 52: 847-851. A semi-quantitative test ([email protected])for myoglobinuria was tested in trauma patients. All test results were evaluated blindly. Test specimens were obtained from 20 patients consecutively admitted with severe multiple trauma (Injury Severity Score: 29; range 26-41). The myoglobin concentration was measured semi-quantitatively by [email protected] three independent observers and quantitatively by enzyme-immuno-assay (EIA). Undiluted as well as 1:2, 1:6, 1:11, and 1:22 diluted samples were used. Test readings were done after 3 min and 5 min, respectively. The [email protected] test classified the myoglobin concentrations correctly in 92.8% of the readings after 3 min and in 87.5% (mean, range: 85.5-91.670) of the readings after 5 min. Conclusion: [email protected] enables immediate bedside diagnosis of myoglobinuria in trauma patients. The test should be performed on both undiluted and 1:6 diluted urine samples with test reading after 5 min.

Key words: rhabdomyolysis; myoglobin; acute renal failure; diagnostic test; multiple trauma; interobserver variation; predictive value of tests; latex fixation tests; enzyme-linked immunosorbent assay; proteinuria. Per Thorgaard Andersen, Leonorevej 6 , 9000 Aalborg C, Denmark

The key point in prevention of renal failure in patientswith rhabdomyolysis is early recognition of myoglobinuria [l], as renal failure develops within hours in untreated patients [2]. Understandably there is a great clinical value for a specific, quick and easy method of myoglobindetermination [3]. We have investigated the performance in a clinical setting of a bed-side latex-agglutination test for [email protected] The test result is available in 3-5 min, thereby permitting

immediate recognition of myoglobinuria and subsequent early therapy.

MATERIALS AND METHODS One urine specimen was obtained from 20 patients with multiple trauma (fractures and contusion of the extremities and trauma to the abdomen, thorax, and/or the skull) on admission to hospital. The injury severity score (ISS) 847

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848

P. Thorguard Andersen et al. absorption solution to a zone on a test plate. The latex solution was added (25 pl) and mixed with urine and absorption solution to cover two-thirds of the reaction zone. The test plate was rotated slowly for 3 min, and the test result was evaluated. The test plate was rotated slowly for additionally 2 min, after which time a new reading of the test result was done. The reagents of [email protected] been standardized to yield positive test results at myoglobin concentrations >6.72 nmol I-', positive or negative test results at myoglobin concentrations between 4.48 nmol I-' and 6.72 nmol I-', and negative test results at myoglobin concentrations 6.72

11 12 11 12 16 7

0 17 0 17 2 15

0 60 0 60 0 60

PTA

LKN

JS

0.855 (0.876-0.923) * 0. I45 (0.077-0.239)

0.855 (0.76 1 - 0.923)* 0.145 (0.077-0.239)

0.916 (0.834-0.965) * 0.084 (0.035-0.166)

850

P. Thorgaard Andersen et al.

fraction of correctly and incorrectly classified urine samples are given for each observer with 95% confidence limits. It should be noted, that with test reading after 5 min all samples with myoglobin concentration exceeding 6.72 nmol I-’ were correctly classified by all three observers.

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DISCUSSION The [email protected] for semi-quantitative measurement of myoglobin in serum has previously been used for rapid diagnosis of acute myocardial infarction [S] and rhabdomyolysis [ 6 ] . Characteristically, these studies described a myoglobin concentration range, in which the test may be either positive or negative (‘borderline range’). However, the existence of a ‘borderline range’ and of false positive test reactions below the ‘borderline range’ is of minor importance in relation to the clinical handling of patients suspected of rhabdomyolysis. The decision to initiate therapy for preservation of renal function (enforcement of diuresis and alkalinization of the urine) would be incorrect. However, the treatment to be initiated is harmless and cheap and may be adjusted, when more sensitive, but also more timeconsuming analytical methods have confirmed or disproved the presence of rhabdomyolysis. False negative [email protected] results would be a much more serious problem. Treatment would not be initiated and renal failure could be the result. False negative test results may occur, when the latex-agglutination test principle is used, both at myoglobin concentrations near the ‘borderline range’ and at very high myoglobin concentrations. The reagent of the latexagglutination test consists of a suspension of latex particles coated with antibodies to human myoglobin. If the serum myoglobin is less than 4.48 nmol I-’, excess antibody prevents immunological crosslinking and visible agglutination (‘prozone phenomenon’), whereas agglutination is readily seen in the zone of equivalence. However, if excess antigen is present, the test yields a false-negative result (‘postzone phenomenon’) [7]. The ‘postzone phenomenon’ has for the [email protected] test been reported at myoglobin concentrations exceeding 280-560 nmol I-’ in undiluted samples 141. In

our study, the highest urinary concentration was 113 nmol I-’. Thus, it was well below the myoglobin concentration previously described to give rise to false negative [email protected] Specimens with a very high myoglobin concentration (>60 Fmol I-’) may be recognized as they are visibly discoloured. Initially the urine is pink, but turns gradually brown as myoglobin is transformed to methmyoglobin [8]. The urinary myoglobin concentration of trauma-patients has been investigated in only one study. Hack1 et a1 [9] investigated prospectively thirty-four patients with ISS of 2823.1 (SEM) with urine myoglobin concentration measurements every 8-h. Mean myoglobin concentration was 1895236 nmol I-’ (SEM) on day 1 decreasing to 44f75 nmol I-’ (SEM) on day 7. Maximal urine myoglobin concentration was 1781 nmol I-’. Thus, dilution of the urine sample should always be performed to avoid the problem with antigen excess, when using a latex-agglutination test in clinical practice. False negative [email protected] were not found in our study, when the tests were evaluated after 5 min, whereas 5 false negative reactions were found after 3 min. As previously stated, it is of utmost importance to avoid false negative test results. With a cut-off limit of 6.72 nmol myoglobin I-’ the test should consequently be evaluated after 5 min. A higher number of false positive test results at this point of time is of minor clinical importance. In conclusion, the [email protected] test enables immediate, bedside diagnosis of myoglobinuria in patients with multiple trauma. The test should be applicated on both undiluted and 1:6 diluted urine samples, with a test reading after 5 min. The test should be used as an immediately available, ‘decision aiding’ diagnostic tool and should be supplemented with other laboratory tests for the final diagnosis and grading of myoglobinuria.

ACKNOWLEDGMENTS Financial support to this study was given by the Ingemann 0. Bucks’s Fund and by the Heinrich Kopp’s Fund. We wish to express our gratitude to Johan Selmer, Novo Immuno-Technology, Copenhagen, for his expert laboratory assistance.

Latex-test f o r rnyoglobinuria

REFERENCES I Warren DJ. Acute renal failure: diagnosis of cause needed within hours. Br Med J 1987; 284:

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1569.

2 Ron D, Taitelman U, Michaelson M, Bar-Joseph G, Bursztein S, Better 0s. Prevention of acute renal failure in traumatic rhabdomyolysis. Arch Intern Med 1984; 144: 277-80. 3 Lillehoj EP, Poulik MD. Normal and abnormal aspects of proteinuria. Exp Pathol1986; 29: 1-28. 4 Toft E, Stentoft J, Andersen PT. False-negative latex-agglutination test for myoglobin owing to antigen excess. Clin Chem 1988; 34: 177. 5 Nerregaard-Hansen K, Hangaard J, NergaardPetersen B. A rapid latex agglutination test for detection of elevated levels of myoglobin in serum and its value in the early diagnosis of acute myocardial infarction. Scand J Clin Lab Invest 1984;44: 99-103.

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6 Andersen PT, Jargensen PJ, Toft E, Nielsen LK, Hansen KN. Rapid estimation of serum myoglobin concentration during rhabdomyolysis with a latexagglutination test ([email protected]).Acta Chir Scand 1990; 156: 515-9. 7 Nakamura RM, Tucker ES. Antibody as reagent. In: Henry JB, ed. Clinical diagnosis and management by laboratory methods. Philadelphia: WB Saunders Co. 1984: 896. 8 Glassock RJ. Hematuria and pigmenturia. In: Massry SG, Glassock RJ, eds. Textbook of nephrology. Baltimore: Williams & Wilkins, 1983: 4.20- 4.24. 9 Hack1 JM, Neumann M, Weirather E, Stroschneider E. Myoglobinfreisetzung und nierenfunktion bei polytraumatisierten intensivpatienten. Anaesthesist 1990;39: 319-22. Received 9 March 1992 Accepted 26 July 1992

Semi-quantitative measurement of myoglobinuria in trauma patients with a latex-agglutination test (Rapi-Tex).

A semi-quantitative test (Rapi-Tex) for myoglobinuria was tested in trauma patients. All test results were evaluated blindly. Test specimens were obta...
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