engleski

PERFORMANCE EVALUATION OF THE ROCHE ELECSYS PAPP-A AND FREE BETA HCG SCREENING ASSAYS

Background. Routine first trimester Down syndrome screening supports an earlier decision-making process and helps to ensure safer pregnancies. We evaluated the performance characteristics of Roche Elecsys screening assays pregnancy-associated plasma protein-A (PAPP-A) and maternal serum free beta-human chorionic gonadotropin (beta-hCG). Methods. PAPP-A and free beta hCG concentrations were measured by electrochemiluminescent (ECL) technology on Roche Elecsys analyzer. Verification of performance for precision was performed based on guidance from the Clinical and Laboratory Standards Institute (CLSI) Document EP15-A2. Participation in the United Kingdom National External Quality Assessment Service (UKNEQAS) scheme for First Trimester Downs Syndrome Screening on monthly basis allowed us to monitor long-term analytical bias and risks calculations for trisomy 21 and 18/13 using SsdwLab 5.0.9 software approved by the Fetal Medicine Foundation. Results. The within-laboratory precision obtained for PAPP-A assay was 2.0% and 2.1% in the low and high concentration level, respectively and 2.7% and 3.3% for free beta hCG measurements, respectively. Expanded measurement uncertainties were ±8.6% and ±7.8% (k=2 representing a confidence level of 95%) in the low and high concentration level for PAPP-A assay and ±6.4% and ±6.8% for free beta hCG measurements, respectively. The long-term results in the UKNEQAS scheme showed acceptable performance with the analytical bias from the method mean within 10% for both assays. Conclusions. The Roche Elecsys serum PAPP-A and free beta hCG assays ensure reliable analytical results with method target values that fall within Fetal Medicine Foundation accreditation targets.

Down syndrome screening; Roche Elecsys screening assays pregnancy-associated plasma protein-A (PAPP-A); maternal serum free beta-human chorionic gonadotropin (beta-hCG)

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