Micro Particle Enzyme Immunoassay (MEIA)-IMxによるHBc抗体の検出

: A new micro particle enzyme immunoassay technique (MEIA, IMx HAVAB, Abbott) has been recently introduced for the detection of antibody to hepatitis A virus (anti-HA). To evaluate the feasibility of the IMx HAVAB, we carried out comparison tests between MEIA, RIA and EIA. Furthermore, we investigated the prevalence of anti-HA in Fukuoka City and Yonaguni Island, Okinawa, Japan using this method. Results obtained were as follows: In the test of 514 sera, 254 (49.0%) were positive by the three methods, and the remaining 260 (50.6%) were negative by the three methods. Examination of diluted sera using IMx revealed that IMx can be used as efficiently as RIA and EIA. Quantitative linear correlations were found between IMx and RIA (r = 0.973), and IMx and EIA (r = 0.969). Anti-HA was assayed within 45 minutes by IMx, and the procedure was simple because of the auto analyser used in this method. On Yonaguni Island, a significant decrease in the overall prevalence of anti-HA from 75.2% in 1980 to 61.1%, in 1990 (p less than 0.05) was found, the prevalence of anti-HA on Yonaguni Island in 1990 was significantly higher than in Fukuoka City (p less than 0.001). These results indicate that the sensitivity of IMx is equivalent to those of RIA and EIA, that it is easier to use than either RIA or EIA and that hepatitis A virus infection in Okinawa, has significantly decreased during the past 10 years, but is still significantly more frequent than in Fukuoka City.