ABSTRACT
A Thailand quality assessment program called "The External Quality Assessment in Clinical Chemistry, EQAC" was found in 1986. Ablind lyophilized control serum is monthly-cycle distributed to the participants and the returned test-report values are evaluated by a computed program. Evaluated report Variance Index Scores (VIS) and grades of test and mean score of all tests are posted back to the participants including a back of "The Newsletter of the EQAC". The development has been indicated by an increasing number of active participants and an improvement due to decreasing Variance Index Scores. In 1998 the program was applied by 324 laboratory participants of which 59% of general hospital and community health hospital laboratory, 29% of private hospital laboratory including polyclinics, and 12% of the others. By now as many as 144 trials of 23 biochemistry tests at different methods were assessed from the EQAC program. Participant communication, knowledge update and enhanced quality encouragement have been managed by mean of participants' VIS from 120 to 93 during 1987-1998.