Analytical Performance and Quality Indicators of Fully Automated Immunoassays for sFlt-1 and PlGF.

BACKGROUND: The ratio of the antiangiogenic factor, soluble fms-like tyrosine kinase 1 (sFlt-1), to the proangiogenic factor, placental growth factor (PlGF), is associated with increased risk of preeclampsia. Here, we describe an analytical evaluation of the Elecsys sFlt-1 and PlGF assays at the first North American site in which they were clinically implemented. METHODS: The analytical evaluation included short- and long-term imprecision, method comparison, accuracy, linearity, sample stability, limit of quantification verification, and measurement uncertainty. Quality indicators were also evaluated, including turnaround time and repeat test frequency. RESULTS: Short-term (13-day) and long-term (12-month) imprecision for sFlt-1 and PlGF were <4% CV. Method comparison (n = 40) between Roche cobas e602 and e411 exhibited r > 0.99 and bias <10%. sFlt-1/PlGF ratio rule-out cutoffs (≤33 and ≤38) and rule-in cutoffs (>38, >85, and >110) exhibited negative percent agreement and positive percent agreement of 100%, respectively (n = 40). During the first 12 months, 257 orders were placed, repeat test frequency was 17.5%, mean time between repeat orders was 23 days, and 72.0% of results were reported within 2 h from sample receipt when quality control was run continuously. CONCLUSIONS: We describe analytical performance parameters and quality indicators of the Elecsys sFlt-1 and PlGF assays, which was the first North American clinical laboratory site to implement these assays in support of the institution's high-risk obstetrical unit.

Evaluation of a point-of-care glucose meter for general use in complex tertiary care facilities.

OBJECTIVE: To evaluate the performance of the StatStrip glucose meter from Nova Biomedical for use in complex tertiary care facilities. METHODS: Performance evaluation was conducted in 6 clinical locations involving nurse end-users. Imprecision (CV)<5% was considered acceptable. Ten substances were examined for potential analytical interferences at two levels and 3 glucose concentrations. Inaccuracy was determined by 386 paired glucose differences between glucose meter and laboratory reference analyses. Acceptability was based on CSLI/ISO15197 criteria. Potential clinical impact was classified under a 5-level severity scheme. RESULTS: Imprecision varied from CV 2.4 to 4.9%. Significant interference was observed only for free hemoglobin at 10 g/L. 97% of paired glucose meter-laboratory differences met CSLI/ISO15197 criteria. All discrepant results had low severity scores. CONCLUSION: The StatStrip glucose meter demonstrated acceptable imprecision and inaccuracy, and was relatively free from common interferences. It should be a good candidate for general use in complex tertiary care facilities.