End user evaluation of DG-PT L Rec, a human recombinant thromboplastin in liquid formulation

The objective is to evaluate Grifols' DG-PT L Rec liquid reagent for prothrombin time (PT) determination in comparison to the laboratory's reference reagent (Siemens' Thromborel S). For linearity, the average master curve for PT and five nominal prothrombin concentrations was obtained from five calibration curves. Within-assay precision (repeatability) was calculated after measuring 20 successive tests of normal and pathological controls. For correlation, 581 routine clinical citrated plasma samples were assessed with both reagents. The BCS XP hemostasis analyzer was used. Linearity of the DG-PT L Rec was good (P < 0.001). The coefficient of variation met the desirable imprecision of less than 2% (normal controls: 1.7%; pathological controls: 0.9%). Correlation between DG-PT L Rec and Thromborel S was high (r = 0.9795; PT in %). In subgroups of anticoagulated, low fibrinogen, lipemic, jaundice, and hemolyzed samples the correlation was more than 0.95. Performance of DG-PT L Rec was high and comparable to the reference reagent.