Analytical performances of the Diazyme ADA assay on the Cobas® 6000 system

ObjectiveTo evaluate the analytical performance of the Diazyme ADA assay on the Cobas® 6000 system for pleural fluid samples analysis.Design and methodsImprecision, linearity, calibration curve stability, interference, and correlation studies were completed.ResultsThe Diazyme ADA assay demonstrated excellent precision (CV < 4%) over the analytical measurement range (0.5-117 U/L). Bilirubin above 50 μmol/L and haemoglobin above 177 μmol/L interfered with the test, inducing a negative and a positive interference respectively. The Diazyme ADA assay correlated well with the Giusti method (r2 = 0.93) but exhibited a negative bias (~ −30%).ConclusionsThe Diazyme ADA assay on the Cobas® 6000 system represents a rapid, accurate, precise and reliable method for determination of ADA activity in pleural fluid samples.