Objective To explore the feasibility of inter-laboratory comparison and trueness evaluation among clinical laboratories, and assess the quality of participants′measurement, by measuring the activity of alanine aminotransferase ( ALT ) in patient serum samples.Methods Method comparison study was used.Five patients serum samples, whose target values were assigned by two international candidate reference laboratory with reference method of ALT without pyridoxal phosphate, were measured by 23 routine laboratories.The bias between measurement result of each participant and the mean of reference laboratories was calculated, and then compared to allowable bias 6%.Calculate the mean value and the relative bias.Results Compared with the mean of reference laboratories, the maximum absolute value of bias among the 23 routine laboratories was 31.27%.The rate range which bias was less than the allowable bias was 26.09%-73.91 %.The bias acceptability of 8 participants were more than or equal to 80%;15 participants were less than or equal to 60%; and 3 participants were 0%.Conclusions Using patient serum samples and values assigned by reference method is an effective way to carry out inter-laboratory comparison and trueness evaluation.It can reflect the quality of measurement more truly.