BACKGROUND: Fecal occult blood test is a useful method for mass screening of colorectal cancer. HM-JACK is automatic analyzer for detecting fecal occult blood with latex agglutination methods. We evaluated its apparatus for compatibility for clinical testing. METHODS: The linearity, precision and effect of temperature and container in stool storage were evaluated. The comparison study with OC-Hemodia and prozone phenomenon were evaluated. RESULTS: The linearity was good(R(2)=0.997) and coeffiecinet variation(CV) of within-day precision were 4.6% and 2.6% in low concentration and high concentration. The CV of between-day precision were 4.8% and 3.5%. The hemoglobin concentration of 0.1 g/dL(1x10(6) ng/mL) was measured to 651 ng/mL for Antigen excess zone. The hemoglobin were more decreased in room temperature storage and usual container storage than in low temperature storage and HM-JACK container storage. The concordance rate between HM-JACK and OC-Hemodia was 90%. CONCLUSION: HM-JACK showed good performance for linearity, precision and comparison study. Therefore, it can be used effectively in clinical laboratory due to convenience, and possibility of quantitation and fast reporting.