A-009 Analytical Evaluation of the High-sensitivity Cardiac Troponin immunoassay

Abstract Background The application of high-sensitivity cardiac troponin is fundamental for the diagnosis and risk assessment of acute myocardial infarction and myocardial injury. This report is a primary evaluation of the analytical and climical performances of two high-sensitivity cardiac troponin assays (hs-cTnI and hs-cTnT) manufactured by Maccura Biotech Co. Ltd. (Chengdu, China). The assays use Maccura chemiluminescence analyzers for full automatic measurement of cardiac troponins in human blood. Methods A single reagent lot and one i 1000 analyzer were used. The CLSI EP17-A2 was followed to assess the LoB and LoD, four Maccura controls without troponins and 4 serum fresh samples with low troponins concentration were analyzed for 5 days with 4 replicates per day (n = 80). The precision was evaluated according to CLSI EP15-A3, 10 serum fresh samples were tested for 10 days with one run per day in 5 replicates per run (n =500). Three samples for precision studies with the troponins concentrations close to the manufacturer gender-specific 99th percentiles (hs-cTnI: 33.5pg/mL for male and 19.8pg/mL for female; hs-cTnT: 15.5pg/mL for male and 10.1pg/mL for female). The residual sera from 1200 healthy individuals (600 of male and female each) who received their regular health check at Deyang People*s Hospital were utilized to validate the rate of detectable (the concentration>LoD). The exclusion criteria include the findings of sample with abnormal levels of NT-proBNP, blood glucose, Creatinine, Uric acid and Urea. Results The LoB and LoD were calculated to be 0.33pg/ml and 1.0pg/ml for hs-cTnI and 0.36pg/ml and 1.22pg/ml for hs-cTnT using a non-parametrical method; therefore, the manufacturer*s claimed LOB and LOD are verified. The precision profiles cover the concentrations from 2.0pg/ml to 1100pg/ml with CVs ranging from 1.4%∼8.0% (repeatability) and 1.7%∼13.1% (within-laboratory imprecision) for hs-cTnI; 1.7%∼8.1% (repeatability) and 2.2%∼12.9% (within-laboratory imprecision) for hs-cTnT. Measurements of 1200 healthy individuals indicate the 99th percentile reference values to be 18.6pg/ml (female) and 31.7pg/ml (male) for hs-cTnI, 10.4pg/ml and 15.8pg/ml for hs-cTnT. The imprecision of <10% at gender-specific 99th percentile values is validated. Measurements of 1200 healthy individuals also indicate 94.7% of unisex samples were above the LoD for hs-cTnI, and 92.0% were above the LoD for hs-cTnT. Conclusion The results of this evaluation demonstrate the two troponin assays manufactured by Maccura obtained optimal sensitivity and precision as defined by IFCC for high sensitivity cardiac troponin assay. The high detection rate in healthy individuals and expected gender specific 99th percentile values support their use as feasible candidates for further clinical investigation.