Serum ASAT, ALAT, ALP, LD, GT, and CK determined in the Cobas-Bio centrifugal analyser by the methods of the Scandinavian Committee on Enzymes

Abstract

The recommended methods of the Scandinavian Committee on Enzymes [4, 5, 6, 7, 8] have been applied to the Cobas-Bio centrifugal analyser. Reagents and serum volumes were scaled down and final molarities were kept equal. Serum volumes in microlitres were as follows: ASAT 30, ALAT 30, ALP 3, LD 5, GT 20, and CK 10. Including the dead space of the sample cup, the volume needed to perform all six tests was 113 μl. Within-run and between-run precision (CV%) were as follows: ASAT 1.32 and 1.95, ALAT 1.68 and 2.93, ALP 1.56 and 3.10, LD 1.63 and 4.44, GT 0.81 and 2.23, and CK 1.02 and 1.94. Mean deviations (%) from target values of two commercial sera were as follows: ASAT −0.3 and −0.4, ALAT −0.4 and −2.2, ALP −1.8 and −7.3, LD 0.4 and −6.2, GT 13.9 and −10.7, and CK −4.9 and −1.3. Results of all the methods correlated well with those obtained with their respective manual methods. Analytical time for 28 samples of each analyte was 10 min, apart from CK which was 14 min. Reagent cost per sample was 0.6, 0.9, 0.1, 0.3, 0.9, and 26 US cents respectively. All reagents were prepared in the laboratory, except those for CK which were bought from J. T. Baker (Phillipsburgh, NJ, USA). In conclusion, the methods keep the features of the manual methods but they are more precise and practicable, much faster and cheaper, and use minimal amounts of sera more convenient for paediatric work.

Key-words:

• alanine aminotransferase
• alkaline phosphatase
• aspartate aminotransferase
• autoanalysis
• automation
• centrigufal analysers
• cost control
• creatine kinase
• glutamyl transpeptidase
• lactate dehydrogenase