Abstract: Objective To analyze the influence of incubation time on the testing of alanine aminotransferase （ALT） by extending its incubation time of the detection reagents in mobile blood collecting. Methods The standard materials for quality control were added to the reagents for ALT measurements at various intervals of incubation time. The results were read immediately with half rate method by semi-automatic biochemical analyzer. The first reading of sample tests at 3 min of incubation was taken as the true value. The deviations of the results were calculated at different intervals of incubation time,and the reliable upper limit of reagents incubation time was obtained. Results The deviation of ALT test results was below 10% on or in 2.5 h. However,the deviation was up to 10.33% or even higher when incubation time was extended. A certain linear relationship between the two factors was found. The permissible error of ALT test results is limited to ± 20% according to American CLIA88 regulations and the deviation should be less than half of the permissible error which is determined as 10% at present observation. The results showed that the reagent incubation time of 2 .5 h is taken as the upper limit. Conclusion Reagent incubation time for ALT detection has remarkable influence on the test results,and 2.5 h would be believed as the incubation time upper limit of the reagents for ALT detection.

Key words: Semi-automatic biochemical analyze, Blood donors, ALT, Incubation, time