The followings are the results for quality assessment in immunoserology for 1999 : 1. Evaluation of external quality assessment was done in 2 trials, the first was participated by 89.0% and the second by 87.8%. 2. The statistics of items that could by quantitated were sent according to the various manufacturer. 3. Test methods for immunoserology laboratory tests were not significantly changed, but slightly increased EIA method comparing with last year. 4. Concordance with the recommended result was highest for anti-HIV, and lowest for HBs Ag, STS-nontreponemal and ASO test.