• P Hedberg, J Valkama, and M Puukka.
• Laboratory of Oulu University Hospital, Department of Clinical Chemistry, University of Oulu, Finland. pirjo.hedberg@ppshp.fi
• Scand. J. Clin. Lab. Invest. 2003 Jan 1; 63 (1): 55-64.

AbstractThe results of an evaluation of the Innotrac Aio! cardiac markers are presented. This system is based on dry-chemistry, time-resolved fluorometry. All assay-specific reagents are dry-coated into assay-specific cups, and only the generic assay buffer is required. The levels of precision attained with pooled serum samples and control materials were acceptable for cTnI and CK-MB. Myoglobin assay showed higher CV, 5.6-9.5%. The linearity studies were performed in concentration ranges of 0.1-76 microg/L for cTnI, 0.7-450 microg/L for CK-MB and 0.6-1500 microg/L for myoglobin. The markers were found to be linear within the ranges tested. The correlation coefficient between the Aio! and AxSYM cTnI assays was 0.960, and the slope was 0.07. The correlation coefficients between the Aio! and AxSYM CK-MB and myoglobin assays were 0.995 and 0.971, respectively. They involved some differences in the measured concentrations (Aio! CK-MB was about 9% higher than AxSYM CK-MB, and Aio! myoglobin was 19% higher than AxSYM). Comparative studies with all the markers, using EDTA whole blood and lithium heparin plasma specimens and lithium heparin whole blood and plasma, yielded the following results: the slopes were close to 1.0 for all correlations, with the exception of that between CK-MB EDTA whole blood and lithium heparin (0.83). High correlation coefficients were obtained (> or = 0.97). The carryover results for all the cardiac markers were good, 0.0%, 0.0%, and 0.3% for cTnI, CK-MB, and myoglobin, respectively. The analytical detection limits were 0.01 microg/L for cTnI, 0.8 microg/L for CK-MB and 0.5 microg/L for myoglobin. The stability of the analytes in the lithium heparin samples at room temperature was also studied and was found to be decreased by from 10% (myoglobin and CK-MB) to 17% (cTnI) in 8 h. Innotrac Aio! provides a rapid and easy quantitative measurement of cardiac TnI, CK-MB, and myoglobin within < 18 min. This system is therefore suitable for use in emergency departments, coronary care units or central laboratory settings.

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