Analytical Performance and Comparability of Three New Coagulation Analyzers

Analytical performance should be evaluated before a new coagulation analyzer is adopted in a clinical laboratory. The objective of this study was to evaluate analytical performances of three new coagulation analyzers (STA-R Max3, CN-6000, and Cobas t511) and compare them based on the following four coagulation parameters: prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen, and D-dimer.

A total of 427 plasma samples, including fresh and frozen/thawed plasma spanning wide ranges. Each of the manufacturers' quality control samples were used for the evaluation. Analytical performances were evaluated. Parameters considered were precision, carryover, verification of analytical measurement range, auto-dilution, and reference range according to the CLSI guidelines (H57-A). The results of each parameter were compared between STA-R compact (currently in use) and three new analyzers using fresh plasma. The results were compared among three new analyzers using fresh and frozen/thawed plasma, and samples with interferences of hemolysis/icterus/ lipemia (H/I/L).

Analytical performances were excellent for all analyzers within each manufacturer's target based on results of precision, carryover, linearity, and verifications of auto-dilution, and reference range. Results for four parameters (PT/aPTT/fibrinogen/D-dimer) with the three new analyzers using fresh samples were well-correlated with those of STA-R Compact except for D-dimer tests (Pearson's r: 0.84 to 1.00). Good correlations were observed between the new analyzers with the total samples (fresh and frozen/thawed samples) (Pearson's r, 0.86 to 0.97). However, weaker correlation and/or higher mean bias% were observed for aPTT and D-dimer with total samples and for four parameters with normal samples rather than abnormal samples across the three analyzers. Differences were more prominent with H/I/L samples, especially between STA-R Max3 and CN-6000 or Cobas t511 for PT, aPTT, and D-dimers.

With excellent analytical performances, the three new coagulation analyzers demonstrated good correlations, although high variabilities were seen for aPTT and D-dimers. High variability in comparison analysis might be mainly attributed to differences in reference and reportable ranges of each parameter across the three different analyzers.