Implementation of a Quality Improvement Program to Improve Sweat Test Performance in a Pediatric Hospital Barina Aqil, MD; Aaron West, BS; Michael Dowlin, BS; Estella Tam, BS; Cristy Nordstrom, BS; Gregory Buffone, PhD; Sridevi Devaraj, PhD, DABCC, FACB
Context.—All positive screening of newborns for cystic fibrosis using the dried blood spot 2-tiered immunoreactive trypsinogen/DNA method requires subsequent sweat chloride testing for confirmation. Obtaining an adequate volume of sweat to measure chloride is a challenge for many cystic fibrosis centers across the nation. The standard for patients older than 3 months is less than 5% quantity not sufficient (QNS) and for patients 3 months or younger is less than 10% QNS. Objective.—To set up a quality improvement (QI) program for sweat testing to improve QNS rates using the Wescor Macroduct (Wescor, Inc, Logan, Utah) method at Texas Children’s Hospital’s laboratory, Houston, Texas. Design.—Single-center study. Results.—Quantity not sufficient rates were evaluated
for 4 months before and 8 months after implementation of the QI program for patients aged 3 months or younger and those older than 3 months. The QI program included changes in technician training, service, site of collection, mode of collection, weekly review, and forms to screen patients for medications that may alter sweat production. A marked improvement was observed in the rates of QNS, which declined considerably from 16.7% to 8.5% (3 months old) and from 9.3% to 2.2% (.3 months old) after implementation of the QI initiative in both age categories. Conclusion.—This report demonstrates the effectiveness of the QI program in significantly improving QNS rates in sweat chloride testing in a pediatric hospital. (Arch Pathol Lab Med. 2014;138:920–922 doi: 10.5858/ arpa.2013-0041-OA)
C
the United States. The CFF requires laboratories to maintain an annual QNS rate of 5% or less for children older than 3 months and an annual QNS rate of 10% or less for neonates and infants 3 months or younger.6 Obtaining adequate volume is a challenge. Because of insufficient volume, repeat testing is required, resulting in anxiety to parents awaiting a definitive diagnosis, loss of cost-effectiveness, and delay in the initiation of therapy. Thus, the aim of our study was to implement a quality improvement (QI) program for sweat chloride testing in children at a pediatric hospital.
ystic fibrosis (CF) is an inherited condition of children and adults. It is due to abnormalities of CF transmembrane conductance regulator protein, impairing transport across the epithelium, including ducts of sweat glands. This causes loss of salt through sweat glands in patients with CF.1 Neonatal screening for CF began in 1979 with elevated immunoreactive trypsinogen in the dried blood spots of newborns.2 There are 2 predominant CF newborn screening algorithms: immunoreactive trypsinogen/immunoreactive trypsinogen and immunoreactive trypsinogen/DNA.3 The collection of sweat by quantitative pilocarpine iontophoresis, where cholinergic drugs are used as stimulators of sweat, is used as the follow-up of abnormal newborn screen and for the establishment of definitive diagnosis.4 One such technique for sweat collection is the macroduct system. The minimum acceptable sweat volume is 15 ll in macroduct coils5; lower volumes are referred to as quantity not sufficient (QNS) specimens, not because the specimen cannot be analyzed but because this is a physiological requirement. The CF Foundation (CFF) published specific guidelines for sweat testing performed by laboratories across
Accepted for publication September 11, 2013. Published as an Early Online Release February 25, 2014. From the Texas Children’s Hospital and Department of Pathology, Baylor College of Medicine, Houston, Texas. The authors have no relevant financial interest in the products or companies described in this article. Reprints: Sridevi Devaraj, PhD, DABCC, FACB, Clinical Chemistry, Texas Children’s Hospital, 6621 Fannin St, Houston, TX 77030 (e-mail: [email protected]). 920 Arch Pathol Lab Med—Vol 138, July 2014
MATERIALS AND METHODS Study Population All infants referred to Texas Children’s Hospital (Houston, Texas) for confirmatory sweat testing following a positive screen from January to December 2012 were included.
Method Sweat testing by pilocarpine iontophoresis using the Wescor Macroduct Sweat Collection System (Wescor, Inc, Logan, Utah) method is used in Texas Children’s Hospital. The sweat test for CF involves 3 consecutive procedures. Sweat Stimulation.—The stimulation of localized sweating is induced by iontophoresis of pilocarpine. Stimulated in this manner, pilocarpine produces sweating in a localized area corresponding in size to the positive electrode. The stimulation and collection areas are the same size in order to standardize the sweat rate and minimize the evaporation or dilution of sweat chloride from unstimulated sweat. Quality Improvement Program for Sweat Testing—Aqil et al
Table 1. 1 2 3 4 5 6 7 8
Changes Adhered To as Part of the Quality Improvement Program
Only infants weighing more than 2 kg and 36 wk postconception were tested Testing was not performed before 48 hours postbirth Parents were instructed to keep patient hydrated (for outpatient collections) Testing was deferred for patients on intravenous infusions in the arm and patients on certain mineralocorticoids Sweat collection from the thigh was eliminated Heel warmer, firm placement of the device, and the use of Parafilm to prevent evaporation were added Staff were retrained and No. of collectors was restricted to 5 Weekly meetings were held to examine QNS rate
Abbreviation: QNS, quantity not sufficient.
Sweat Collection.—Following stimulation, the skin is cleansed with distilled or deionized water and thoroughly dried. Sweat can then be collected on the same area by microbore tubing and is measured on a chloridometer. Sweat Analysis.—The Labconco Digital Chloridometer (Labconco, Kansas City, Missouri) is a coulometric titrator designed to determine the chloride ion concentration of a solution. The combination of silver ions and chloride ions is a quantitative reaction that results in an insoluble precipitate of silver chloride. The percentage coefficient of variation for measurement of chloride on the chloridometer is less than 7% (range 22–110 mmol/ L chloride). Quantity not sufficient is defined as sample volume less than 15 ll in the coils from each of the 2 collecting sites in a 30minute period. Changes to the sweat testing protocol were made in accordance with Clinical and Laboratory Standards Institute (CLSI)5 guideline C34-A3; all these changes and additional ones that were implemented are listed in Table 1. Adherence to the above guidelines was monitored. The QNS rates for patients younger than 3 months and for patients 3 months or older were compared before and after the QI program statistically by 2-proportion confidence interval testing, and P , .05 was considered significant.
RESULTS The testing was performed as per CLSI5 and considering CFF guidelines in the clinical laboratory of the main hospital. For the first 4 months (January–April 2012), the number of sweat tests performed for neonates and infants 3 months or younger and for infants older than 3 months were 42 and 227, respectively. The QNS rates were very high: 16.7% (for age 3 months) and 9.3% (for age .3 months). With the implementation of the program defined in Table 1 by trained staff for subsequent months (May–December 2012), the rates of QNS declined considerably to 8.5% (3 months old) and 2.2% (.3 months old). Total number of sweat tests performed for neonates and infants aged 3 months or younger versus infants older than 3 months were 82 and 358, respectively. Table 2 gives QNS rates before and after the QI program. The decrease in QNS rates was significant regardless of age, that is, whether patients were 3 months or younger or older than 3 months. COMMENT Determining QNS rates is important, as a high rate signifies a problem in sweat collection. Routine monitoring Arch Pathol Lab Med—Vol 138, July 2014
Table 2. Quantity Not Sufficient (QNS) Rates Before and After Implementation of the Quality Improvement Program, %a Patient Age, mo Period January–April May–December a
3 16.7 8.5
.3 9.3 2.2
P ¼ .003 compared with before implementation for age 3 months and P ¼ .001 compared with before implementation for age .3 months.
of the QNS rate should be implemented to establish a sweat testing protocol. In our hospital the upward trend of high QNS rates that were not in alignment with CFF guidelines was concerning. Despite detailed CLSI guidelines for sweat testing procedures, QNS rates could not be maintained per CLSI guidelines for a CFF-accredited center.5 This necessitated the implementation of a series of steps as outlined in our QI program, which included some of the guidelines set forth already by CLSI.5 Thus, in essence, we monitored our strict adherence to the CLSI guidelines. This study demonstrates that the QI program implemented significantly improved QNS rates of sweat testing in both age groups. This short report provides a comprehensive list of changes that clinical laboratories, especially those associated with a CFF-accredited center, should make to obtain the targeted QNS rates. Implementation requires constant vigilance and attention to factors outlined in this report. Gradually problems were identified and rectified with proper reasoning, considering facts such as that during the first 24 hours after birth, sweat electrolyte values are transiently elevated. Beginning on the second day after birth, electrolyte concentration rapidly declines. Therefore, we reasoned that sweat testing should be not performed on infants younger than 36 weeks postconception and not before 48 hours after birth, as outlined by the CLSI guideline5 in points 8.2 and 8.7.2. Hardy et al7 also demonstrated transient elevation of sweat electrolytes during the first 24 hours of life. Prior to this report, we had followed the guideline of not doing sweat testing before 48 hours after birth, but had not followed the guideline of not performing it on infants younger than 36 weeks postconception. Infants should be properly hydrated and not on intravenous fluids, as dehydration decreases sweat production. It is important to note that the inclusion of simple instructions at the time of scheduling the sweat collection, especially to outpatients, regarding sufficient hydration significantly improved hydration status, and sweat collection QNS rates were significantly lower. The use of mineralocorticoids can also decrease sweat electrolyte concentrations,8 so patients on such medications should have testing deferred. Although this recommendation is outlined in CLSI 8.3, it was previously not adhered to, and we implemented this change. Application of electrodes for stimulation and collection on legs should be avoided, as there are fewer sweat glands in these locations and the sweat produced is not easily accessible. Freinkel and Woodley9 describe the presence of double the number of sweat glands on arms compared with legs. This is also suggested in the CLSI document. In the Quality Improvement Program for Sweat Testing—Aqil et al 921
present study, elimination of collection of sweat from the legs led to improvement in our QNS rates. Furthermore, the use of a heel warmer leads to an increase in sweat production and, when combined with Parafilm to avoid evaporation, leads to an adequate amount of sweat obtained for analyses. Although previous studies have shown that the addition of a heel warmer by itself does not increase sweat volume,10 in the present study, inclusion of the different techniques—firm placement of device, heel warmer, and Parafilm—significantly improved collection of sweat. The CLSI guideline 8.3 states that sweat can be collected with equivalent electrolyte concentration from the thigh, although the density of sweat glands is lower in the thigh, making it a less optimal collection site. In our setting, despite the use of the macroduct collector, which minimizes evaporation, addition of Parafilm resulted in increased sweat collection volume. The CLSI guideline 8.5.4 addresses the issue of fastening the microbore tubing collector with firm strap pressure; however, this was not adequately followed in our setting before the implementation of the proper guidelines. Proper training of the staff and limiting the number of people performing the test improved the consistency of the results. Additional training given to the technical staff included in-service training by one of the CF coordinators, retraining by one of the experienced technologists, and use of PowerPoint presentations to emphasize the salient features of sweat collection, as well as review of all cases that had ineffective sweat volumes for plausible causes. The number of technicians performing the test was decreased by 33%. Weekly meetings to assess QNS rates and technical performance and to highlight difficulties in performance and assessment also brought out drastic changes during the evaluation period.
922 Arch Pathol Lab Med—Vol 138, July 2014
In conclusion, with the implementation of a QI program in our pediatric hospital, we were able to achieve a marked drop in QNS rates, from 16.7% to 8.5% (for patients aged 3 months) and from 9.3% to 2.2% (for patients aged .3 months). Reduction of QNS rates and more frequent periodic on-site assessment are required for sweat testing to achieve its full diagnostic potential. This detailed QI program provides practice guidelines for achieving low QNS rates and conformation to national guidelines for clinical labs at CF centers. References 1. Welsh MJ, Ramsey BW, Accurso F, Cutting GR. Cystic fibrosis. In: Scriver C, Beaudet A, Sly WS, Valle D, Childs B, Kinzler KW, Vogelstein B, eds. The Metabolic and Molecular Bases of Inherited Disease. New York, NY: McGrawHill; 2001:5121–5187. 2. Crossley JR, Elliott RB, Smith PA. Dried-blood spot screening for cystic fibrosis in the newborn. Lancet. 1979;1(8114):472–474. 3. Farrell P, Cutting GR, Earley MC, et al. Newborn Screening for Cystic Fibrosis: Approved Guideline. Wayne, PA: Clinical and Laboratory Standards Institute; 2011. CLSI document I/LA35-A. 4. Gibson L, Cooke E. A test for concentration of electrolytes in sweat in cystic fibrosis of the pancreas utilizing pilocarpine by iontophoresis. Pediatrics. 1959; 23(3):545–549. 5. LeGrys VA, Applequist R, Briscoe DR, et al. Sweat Testing: Sample Collection and Quantitative Chloride Analysis: Approved Guideline. 3rd ed. Wayne, PA: Clinical and Laboratory Standards Institute; 2009. CLSI document C34-A3. 6. Farrell PM, Rosenstein BJ, White TB, et al; Cystic Fibrosis Foundation. Guidelines for diagnosis of cystic fibrosis in newborns through older adults: Cystic Fibrosis Foundation consensus report. J Pediatr. 2008;153(2):S4–S14. 7. Hardy JD, Davison SH, Higgins MU, Polycarpou PN. Sweat tests in the newborn period. Arch Dis Child. 1973;48(4):316–318. 8. LeGrys VA. Sweat testing for the diagnosis of cystic fibrosis: practical considerations. J Pediatr. 1996;129(6):892–897. 9. Freinkel RK, Woodley DT. Biology of Skin. New York, NY: Parthenon Publishing Group Limited; 2001:47–48. 10. Legrys VA, McColley SA, Farrell PM. The need for quality improvement in sweat testing infants after newborn screening for cystic fibrosis. J Pediatr. 2010; 157(6):1035–1037.
Quality Improvement Program for Sweat Testing—Aqil et al
Context.—All positive screening of newborns for cystic fibrosis using the dried blood spot 2-tiered immunoreactive trypsinogen/DNA method requires subsequent sweat chloride testing for confirmation. Obtaining an adequate volume of sweat to measure chloride is a challenge for many cystic fibrosis centers across the nation. The standard for patients older than 3 months is less than 5% quantity not sufficient (QNS) and for patients 3 months or younger is less than 10% QNS. Objective.—To set up a quality improvement (QI) program for sweat testing to improve QNS rates using the Wescor Macroduct (Wescor, Inc, Logan, Utah) method at Texas Children’s Hospital’s laboratory, Houston, Texas. Design.—Single-center study. Results.—Quantity not sufficient rates were evaluated
for 4 months before and 8 months after implementation of the QI program for patients aged 3 months or younger and those older than 3 months. The QI program included changes in technician training, service, site of collection, mode of collection, weekly review, and forms to screen patients for medications that may alter sweat production. A marked improvement was observed in the rates of QNS, which declined considerably from 16.7% to 8.5% (3 months old) and from 9.3% to 2.2% (.3 months old) after implementation of the QI initiative in both age categories. Conclusion.—This report demonstrates the effectiveness of the QI program in significantly improving QNS rates in sweat chloride testing in a pediatric hospital. (Arch Pathol Lab Med. 2014;138:920–922 doi: 10.5858/ arpa.2013-0041-OA)
C
the United States. The CFF requires laboratories to maintain an annual QNS rate of 5% or less for children older than 3 months and an annual QNS rate of 10% or less for neonates and infants 3 months or younger.6 Obtaining adequate volume is a challenge. Because of insufficient volume, repeat testing is required, resulting in anxiety to parents awaiting a definitive diagnosis, loss of cost-effectiveness, and delay in the initiation of therapy. Thus, the aim of our study was to implement a quality improvement (QI) program for sweat chloride testing in children at a pediatric hospital.
ystic fibrosis (CF) is an inherited condition of children and adults. It is due to abnormalities of CF transmembrane conductance regulator protein, impairing transport across the epithelium, including ducts of sweat glands. This causes loss of salt through sweat glands in patients with CF.1 Neonatal screening for CF began in 1979 with elevated immunoreactive trypsinogen in the dried blood spots of newborns.2 There are 2 predominant CF newborn screening algorithms: immunoreactive trypsinogen/immunoreactive trypsinogen and immunoreactive trypsinogen/DNA.3 The collection of sweat by quantitative pilocarpine iontophoresis, where cholinergic drugs are used as stimulators of sweat, is used as the follow-up of abnormal newborn screen and for the establishment of definitive diagnosis.4 One such technique for sweat collection is the macroduct system. The minimum acceptable sweat volume is 15 ll in macroduct coils5; lower volumes are referred to as quantity not sufficient (QNS) specimens, not because the specimen cannot be analyzed but because this is a physiological requirement. The CF Foundation (CFF) published specific guidelines for sweat testing performed by laboratories across
Accepted for publication September 11, 2013. Published as an Early Online Release February 25, 2014. From the Texas Children’s Hospital and Department of Pathology, Baylor College of Medicine, Houston, Texas. The authors have no relevant financial interest in the products or companies described in this article. Reprints: Sridevi Devaraj, PhD, DABCC, FACB, Clinical Chemistry, Texas Children’s Hospital, 6621 Fannin St, Houston, TX 77030 (e-mail: [email protected]). 920 Arch Pathol Lab Med—Vol 138, July 2014
MATERIALS AND METHODS Study Population All infants referred to Texas Children’s Hospital (Houston, Texas) for confirmatory sweat testing following a positive screen from January to December 2012 were included.
Method Sweat testing by pilocarpine iontophoresis using the Wescor Macroduct Sweat Collection System (Wescor, Inc, Logan, Utah) method is used in Texas Children’s Hospital. The sweat test for CF involves 3 consecutive procedures. Sweat Stimulation.—The stimulation of localized sweating is induced by iontophoresis of pilocarpine. Stimulated in this manner, pilocarpine produces sweating in a localized area corresponding in size to the positive electrode. The stimulation and collection areas are the same size in order to standardize the sweat rate and minimize the evaporation or dilution of sweat chloride from unstimulated sweat. Quality Improvement Program for Sweat Testing—Aqil et al
Table 1. 1 2 3 4 5 6 7 8
Changes Adhered To as Part of the Quality Improvement Program
Only infants weighing more than 2 kg and 36 wk postconception were tested Testing was not performed before 48 hours postbirth Parents were instructed to keep patient hydrated (for outpatient collections) Testing was deferred for patients on intravenous infusions in the arm and patients on certain mineralocorticoids Sweat collection from the thigh was eliminated Heel warmer, firm placement of the device, and the use of Parafilm to prevent evaporation were added Staff were retrained and No. of collectors was restricted to 5 Weekly meetings were held to examine QNS rate
Abbreviation: QNS, quantity not sufficient.
Sweat Collection.—Following stimulation, the skin is cleansed with distilled or deionized water and thoroughly dried. Sweat can then be collected on the same area by microbore tubing and is measured on a chloridometer. Sweat Analysis.—The Labconco Digital Chloridometer (Labconco, Kansas City, Missouri) is a coulometric titrator designed to determine the chloride ion concentration of a solution. The combination of silver ions and chloride ions is a quantitative reaction that results in an insoluble precipitate of silver chloride. The percentage coefficient of variation for measurement of chloride on the chloridometer is less than 7% (range 22–110 mmol/ L chloride). Quantity not sufficient is defined as sample volume less than 15 ll in the coils from each of the 2 collecting sites in a 30minute period. Changes to the sweat testing protocol were made in accordance with Clinical and Laboratory Standards Institute (CLSI)5 guideline C34-A3; all these changes and additional ones that were implemented are listed in Table 1. Adherence to the above guidelines was monitored. The QNS rates for patients younger than 3 months and for patients 3 months or older were compared before and after the QI program statistically by 2-proportion confidence interval testing, and P , .05 was considered significant.
RESULTS The testing was performed as per CLSI5 and considering CFF guidelines in the clinical laboratory of the main hospital. For the first 4 months (January–April 2012), the number of sweat tests performed for neonates and infants 3 months or younger and for infants older than 3 months were 42 and 227, respectively. The QNS rates were very high: 16.7% (for age 3 months) and 9.3% (for age .3 months). With the implementation of the program defined in Table 1 by trained staff for subsequent months (May–December 2012), the rates of QNS declined considerably to 8.5% (3 months old) and 2.2% (.3 months old). Total number of sweat tests performed for neonates and infants aged 3 months or younger versus infants older than 3 months were 82 and 358, respectively. Table 2 gives QNS rates before and after the QI program. The decrease in QNS rates was significant regardless of age, that is, whether patients were 3 months or younger or older than 3 months. COMMENT Determining QNS rates is important, as a high rate signifies a problem in sweat collection. Routine monitoring Arch Pathol Lab Med—Vol 138, July 2014
Table 2. Quantity Not Sufficient (QNS) Rates Before and After Implementation of the Quality Improvement Program, %a Patient Age, mo Period January–April May–December a
3 16.7 8.5
.3 9.3 2.2
P ¼ .003 compared with before implementation for age 3 months and P ¼ .001 compared with before implementation for age .3 months.
of the QNS rate should be implemented to establish a sweat testing protocol. In our hospital the upward trend of high QNS rates that were not in alignment with CFF guidelines was concerning. Despite detailed CLSI guidelines for sweat testing procedures, QNS rates could not be maintained per CLSI guidelines for a CFF-accredited center.5 This necessitated the implementation of a series of steps as outlined in our QI program, which included some of the guidelines set forth already by CLSI.5 Thus, in essence, we monitored our strict adherence to the CLSI guidelines. This study demonstrates that the QI program implemented significantly improved QNS rates of sweat testing in both age groups. This short report provides a comprehensive list of changes that clinical laboratories, especially those associated with a CFF-accredited center, should make to obtain the targeted QNS rates. Implementation requires constant vigilance and attention to factors outlined in this report. Gradually problems were identified and rectified with proper reasoning, considering facts such as that during the first 24 hours after birth, sweat electrolyte values are transiently elevated. Beginning on the second day after birth, electrolyte concentration rapidly declines. Therefore, we reasoned that sweat testing should be not performed on infants younger than 36 weeks postconception and not before 48 hours after birth, as outlined by the CLSI guideline5 in points 8.2 and 8.7.2. Hardy et al7 also demonstrated transient elevation of sweat electrolytes during the first 24 hours of life. Prior to this report, we had followed the guideline of not doing sweat testing before 48 hours after birth, but had not followed the guideline of not performing it on infants younger than 36 weeks postconception. Infants should be properly hydrated and not on intravenous fluids, as dehydration decreases sweat production. It is important to note that the inclusion of simple instructions at the time of scheduling the sweat collection, especially to outpatients, regarding sufficient hydration significantly improved hydration status, and sweat collection QNS rates were significantly lower. The use of mineralocorticoids can also decrease sweat electrolyte concentrations,8 so patients on such medications should have testing deferred. Although this recommendation is outlined in CLSI 8.3, it was previously not adhered to, and we implemented this change. Application of electrodes for stimulation and collection on legs should be avoided, as there are fewer sweat glands in these locations and the sweat produced is not easily accessible. Freinkel and Woodley9 describe the presence of double the number of sweat glands on arms compared with legs. This is also suggested in the CLSI document. In the Quality Improvement Program for Sweat Testing—Aqil et al 921
present study, elimination of collection of sweat from the legs led to improvement in our QNS rates. Furthermore, the use of a heel warmer leads to an increase in sweat production and, when combined with Parafilm to avoid evaporation, leads to an adequate amount of sweat obtained for analyses. Although previous studies have shown that the addition of a heel warmer by itself does not increase sweat volume,10 in the present study, inclusion of the different techniques—firm placement of device, heel warmer, and Parafilm—significantly improved collection of sweat. The CLSI guideline 8.3 states that sweat can be collected with equivalent electrolyte concentration from the thigh, although the density of sweat glands is lower in the thigh, making it a less optimal collection site. In our setting, despite the use of the macroduct collector, which minimizes evaporation, addition of Parafilm resulted in increased sweat collection volume. The CLSI guideline 8.5.4 addresses the issue of fastening the microbore tubing collector with firm strap pressure; however, this was not adequately followed in our setting before the implementation of the proper guidelines. Proper training of the staff and limiting the number of people performing the test improved the consistency of the results. Additional training given to the technical staff included in-service training by one of the CF coordinators, retraining by one of the experienced technologists, and use of PowerPoint presentations to emphasize the salient features of sweat collection, as well as review of all cases that had ineffective sweat volumes for plausible causes. The number of technicians performing the test was decreased by 33%. Weekly meetings to assess QNS rates and technical performance and to highlight difficulties in performance and assessment also brought out drastic changes during the evaluation period.
922 Arch Pathol Lab Med—Vol 138, July 2014
In conclusion, with the implementation of a QI program in our pediatric hospital, we were able to achieve a marked drop in QNS rates, from 16.7% to 8.5% (for patients aged 3 months) and from 9.3% to 2.2% (for patients aged .3 months). Reduction of QNS rates and more frequent periodic on-site assessment are required for sweat testing to achieve its full diagnostic potential. This detailed QI program provides practice guidelines for achieving low QNS rates and conformation to national guidelines for clinical labs at CF centers. References 1. Welsh MJ, Ramsey BW, Accurso F, Cutting GR. Cystic fibrosis. In: Scriver C, Beaudet A, Sly WS, Valle D, Childs B, Kinzler KW, Vogelstein B, eds. The Metabolic and Molecular Bases of Inherited Disease. New York, NY: McGrawHill; 2001:5121–5187. 2. Crossley JR, Elliott RB, Smith PA. Dried-blood spot screening for cystic fibrosis in the newborn. Lancet. 1979;1(8114):472–474. 3. Farrell P, Cutting GR, Earley MC, et al. Newborn Screening for Cystic Fibrosis: Approved Guideline. Wayne, PA: Clinical and Laboratory Standards Institute; 2011. CLSI document I/LA35-A. 4. Gibson L, Cooke E. A test for concentration of electrolytes in sweat in cystic fibrosis of the pancreas utilizing pilocarpine by iontophoresis. Pediatrics. 1959; 23(3):545–549. 5. LeGrys VA, Applequist R, Briscoe DR, et al. Sweat Testing: Sample Collection and Quantitative Chloride Analysis: Approved Guideline. 3rd ed. Wayne, PA: Clinical and Laboratory Standards Institute; 2009. CLSI document C34-A3. 6. Farrell PM, Rosenstein BJ, White TB, et al; Cystic Fibrosis Foundation. Guidelines for diagnosis of cystic fibrosis in newborns through older adults: Cystic Fibrosis Foundation consensus report. J Pediatr. 2008;153(2):S4–S14. 7. Hardy JD, Davison SH, Higgins MU, Polycarpou PN. Sweat tests in the newborn period. Arch Dis Child. 1973;48(4):316–318. 8. LeGrys VA. Sweat testing for the diagnosis of cystic fibrosis: practical considerations. J Pediatr. 1996;129(6):892–897. 9. Freinkel RK, Woodley DT. Biology of Skin. New York, NY: Parthenon Publishing Group Limited; 2001:47–48. 10. Legrys VA, McColley SA, Farrell PM. The need for quality improvement in sweat testing infants after newborn screening for cystic fibrosis. J Pediatr. 2010; 157(6):1035–1037.
Quality Improvement Program for Sweat Testing—Aqil et al
