BACKGROUND: Before the introduction of the antinuclear antibody test (ANA), the lupus erythematosus (LE) cell test was a useful diagnostic test for systemic lupus erythematosus(SLE) But, the ANA test has replaced the LE cell test in virtually all laboratories as the current routine test for SLE. However, because the LE cell test is still performed in some laboratories, the authors compared the LE cell test with the ANA test to reevaluate the LE cell test. METHODS: A total of 522 cases were evaluated from Aug. 1990 to Aug. 1994. In these cases, the LE cell test and the ANA test were performed simultaneously, and the results were compared. The authors defined the 'True LE Phenomenon' as only when the LE cell test results agreed with the anti-histone antibody pattern of the ANA test. RESULTS: Of the total 522 cases, 56 cases(10.7%) were SLE. The LE cell test was positive in 22 cases(39.3%) and the ANA test in 56 cases(100%). The LE cell test produced 6(27%) false positive cases and 3 (8.8%) false negative cases. Therefore, the sensitivity of the LE cell test that was verified by the ANA test was only 28.6%. On the other hand, the sensitivity of the ANA test was 100%. In 2 cases, the LE cell results were different in repetitive tests although the ANA results were the same. In 2 other cases, it was impossible to interprete the results of the LE cell test because of severe leukopenia. CONCLUSIONS: The authors concluded that the LE cell test showed markedly low sensitivity and a high false positive and false negative rates for SLE, and that the LE cell test was difficult to perform and interpret accurately due to numerous interfering factors. Therefore, for accurate diagnosis of SLE, the LE cell test must be replaced by more definitive and quantitative immunologic tests in all laboratories such as the ANA test.