(75) Quality Improvement Initiative in Sweat Chloride Testing at the WMed Health Cystic Fibrosis Program and Bronson Methodist Hospital

Background: Sweat chloride testing is widely recognized as the gold standard for Cystic Fibrosis (CF) diagnosis [1]. To maintain accuracy, the amount of sweat collected must reach a minimum threshold, or the sample is designated quantity not sufficient (QNS). This requires repeat sweat chloride collection at a later date, which may result in parental stress and delay in initiation of therapy [2]. In 2020, the quickly expanding CF Program at Western Michigan University (WMed) in Kalamazoo, Michigan did not meet the standard limit for QNS rate as required by the Cystic Fibrosis Foundation (CFF). In December 2020, a multidisciplinary team from the WMed CF Program commenced a Quality Improvement (QI) project in conjunction with the Bronson Methodist Hospital (BMH) lab to decrease the QNS rate by November 30, 2021. The goal was to decrease the QNS rate for patients older than 3 months of age from 5.4% to the CFF-recommended QNS rate [3] of 5%. Additionally, for patients 6 weeks to 3 months of age, we aimed to decrease the QNS rate of 28.6% to less than 10%.

Methods: This QI project identified seven unique areas for process improvement: appropriate patient selection, updating BMH lab procedure, technician training, reducing the number of technicians performing analysis, updating nomenclature in the report, reporting right and left chloride concentration, and improving education regarding appropriate timing to order sweat chloride. Some of the many initiatives to address these areas included only allowing inpatient sweat chloride testing with permission from the lab medical director or CF program director; education for providers ordering sweat chloride testing; and in-service training under the expert guidance of Dr. Vicky LeGrys for the BMH lab team to review and perfect sweat chloride analysis techniques.

Results: At the beginning of the QI initiative, QNS for patients >3 months was 5.4% (3/56), and for patients 6 weeks to 3 months was 28.6% (2/7) in the 2020 fiscal year. At the end of the 12-month period, QNS had been decreased to 4.4% (2/45) for patients >3 months and to 0% (0/2) for patients 6 weeks to 3 months (Figure 1).

Conclusions: The WMed CF Program, in collaboration with the BMH laboratory, successfully reduced their QNS rate below the CFF-required threshold, decreasing the burden of repeat testing for families and establishing earlier CF diagnoses. Additional education and optimization of training has also led to improved laboratory processes and renewed confidence in the accuracy of sweat chloride testing performed at BMH. We hope to continue these positive changes by instituting annual sweat chloride trainings for technicians, performing annual reviews of testing procedures, and monthly monitoring of QNS rates throughout the year.

Acknowledgements:

References: [1] Farrell PM, White TB, Ren CL, Hempstead SE, Accurso F, Derichs N, et al. Diagnosis of cystic fibrosis: Consensus guidelines from the cystic fibrosis foundation. J Pediatr. 2017;181:S4-S15.e1. https://dx.doi.org/10.1016/j.jpeds.2016.09.064

[2] Laguna TA, Lin N, Wang Q, Holme B, McNamara J, Regelmann WE. Comparison of quantitative sweat chloride methods after positive newborn screen for cystic fibrosis: Sweat Testing for CF in Newborn Screened Infants. Pediatr Pulmonol. 2012;47(8):736–42. https://dx.doi.org/10.1002/ppul.21608

[3] Legrys VA, McColley SA, Li Z, Farrell PM. The need for quality improvement in sweat testing infants after newborn screening for cystic fibrosis. J Pediatr. 2010;157(6):1035–7. https://dx.doi.org/10.1016/j.jpeds.2010.07.053