Management of Cytomegalovirus, Epstein-Barr Virus, and HIV Viral Load Quality Control Data Using Unity Real Time.

Quality control (QC) rules (Westgard rules) are applied to viral load testing to identify runs that should be reviewed or repeated, but this requires balancing the patient safety benefits of error detection with the cost and inefficiency of false rejection. In this study, we identified the total allowable errors (TEa) from the literature and utilized a commercially available software program (Unity Real Time; Bio-Rad Laboratories) to manage QC data, assess assay performance, and provide QC decision support for both FDA-approved/cleared (Abbott cytomegalovirus [CMV] and HIV viral load) as well as laboratory-developed (Epstein-Barr virus [EBV] viral load) assays. Unity Real Time was used to calculate means, standard deviations (SDs), and coefficient of variation (CV; in percent) of negative, low-positive, and high-positive control data from 73 to 83 days of testing. Sigma values were calculated to measure the test performance relative to a TEa of 0.5 log10. The sigma value of 5.06 for EBV predicts ∼230 erroneous results per million individual patient tests (0.02% frequency), whereas sigma values of >6 for CMV (11.32) and HIV (7.66) indicate <4 erroneous results per million individual patient tests. The Unity Real Time QC Design module utilized these sigma values to recommend QC rules and provided objective evidence for loosening the laboratory's existing QC rules for run acceptability, potentially reducing false rejection rates by 10-fold for the assay with the most variation (EBV viral load). This study provides a framework for laboratories, with Unity Real Time as a tool, to evaluate assay performance relative to clinical decision points and establish optimal rules for routine monitoring of molecular viral load assay performance.

Evaluation and operationalization of commercial serum indices quality control material in the clinical laboratory.

BACKGROUND: Evaluation of specimen suitability for downstream analytical testing and identification of potential interferents in the clinical laboratory is critical for the generation of actionable clinical results. Within the clinical laboratory, hemolysis, icterus, and lipemia are commonly assessed spectrophotometrically. While clinical laboratories rely on analyte-specific quality control (QC) materials to monitor test or instrument performance, QC materials evaluating specimen integrity checks are infrequently implemented. METHODS: Using commercially available specimen integrity materials, we evaluated the Bio-Rad Liquichek™ Serum Indices product on Roche cobas® c701 analyzers at a large academic medical center. Target arbitrary values for the hemolysis, icterus, and lipemia QC materials were 200, 20, and 500, respectively. Means, standard deviations (SD), and coefficients of variation (%CV) were established for hemolysis, icterus, lipemia, and non-interfered QCs, and performance was monitored over a 60-day period. RESULTS: Across four c701 instruments, all QC materials performed well, with %CVs ≤ 1.76%, 4.51%, and 3.46% for hemolysis, icterus, and lipemia QC, respectively. CONCLUSIONS: The Bio-Rad Liquichek Serum Indices product can serve as an effective means of monitoring specimen integrity checks in a manner congruous with existing QC programs.