Evaluierung von Troponin I-, CK- MB- und Myoglobinassay am DPC IMMULITE 2500 Immunoanalyyer

The IMMULITE 2500 (Diagnostic Products Corporation, USA) is a new immunoassay analyzer with Logic Driven Incubation (LDI) capability for easy imcorporation of STAT assays. The IMMULITE 2500 has two incubator tracks that shuttle STAT samples for priority processing, with a time-to-first-result of 15 minutes (incubation time of 10 min) for Myoglobin, CK-MB and Troponin. Within-run imprecision (n=20, patient samples) was determined for 3 different concentrations (cut-off, elevated and high) for all three analytes. In addition within-run imprecision (n=20) was also determined for the specified control materials. The coefficients of variation (CVs) were in the range from 1.9 to 3.4% for Myoglobin (11.7 to 620.0 ng/ml), 3.8 to 5.8 % for CK-MB (4.7 to 412.3 ng/ml) and 3.3 to 5.3 % for Troponin I (0.8 to 90.9 ng/ml). Between-run imprecision (n=20) showed CVs in the range from 3.9 to 6.8 % (Myoglobin, 9,6 to 578,8 ng/ml), 4.1 to 9.1 % (CK-MB, 4.1 to 416.7 ng/ml) and 5.0 to 10.3 % (Troponin I, 0,8 to 93,4 ng/ml). Linearity was tested for troponin up to 91.0 ng/ml (r = 0.9985) myoglobin up to 640 ng/ml (r = 0.9998) and CK-MB up to 400 ng/ml (r = 0.9999). For all three assays no carry over was found with alternating very high and low concentrations (n=20). For method comparison (Passing/Bablok and Bland/Altman) patient samples (n=144) were analyzed for CK- MB and myoglobin at the IMMULITE 2500 and at the ADVIA Centaur (Bayer) and for Troponin I the IMMULITE Turbo assay was used additionally as third method. Data analysis showed good correlation for all methods with the best being between the new IMMULITE 2500 Troponin I and the IMMULITE Turbo Troponin I assay. The good analytical performance shown here and the short time-to-first-result of 15 minutes will certainly improve especially the assessment of cardiac episodes in the emergency room.