Duchenne Muscular Dystrophy (DMD) is a fatal X-linked disorder with a birth prevalence of 19.8:100,000 males worldwide. Elevated concentration of the muscle enzyme creatine kinase-MM (CK-MM) allows for presymptomatic screening of newborns using Dried Blood Spots (DBS). We evaluated imprecision and carryover of the FDA-approved PerkinElmer GSP Neonatal CK-MM kit over multiple runs, days, and operators, followed by quantification of CK-MM loss in stored newborn, contrived, and non-newborn patient DBS resulting from exposure to ambient versus low humidity (50-day trial), and high humidity and high temperature (8-day trial). Imprecision %CV was ≤14% for all verification comparisons and over 6 months of testing. On average, the mean CK-MM recovery after 50 days was >80% of initial concentration for all sample types stored in low humidity and <80% in ambient humidity. After 8 days of storage in high humidity and high temperature, the mean recovery for newborn samples was <80%. Verification results for the GSP Neonatal CK-MM assay were concordant with kit parameters and the assay performed consistently over 6 months. CK-MM degradation in ambient storage can be mitigated by reducing exposure to humidity. Assessment of DBS shipping and storage conditions is recommended prior to implementing DMD screening.
Evaluation of the GSP creatine kinase-MM assay and assessment of CK-MM stability in newborn, patient, and contrived dried blood spots for newborn screening for Duchenne muscular dystrophy
Migliore, B., Zhou, L., Duparc, M., Robles, V., Rehder, C., Peay, H., & Kucera, K. (2022). Evaluation of the GSP creatine kinase-MM assay and assessment of CK-MM stability in newborn, patient, and contrived dried blood spots for newborn screening for Duchenne muscular dystrophy. International Journal of Neonatal Screening, 8(1), . https://doi.org/10.3390/ijns8010012