Rapid Tests for Hepatitis B

雪绒花

Detection of hepatitis B surface antigen (HbsAg) identifies individuals infected with the hepatitis B virus. Quantitative enzyme immunoasssay (EIA) methods are considered to be the most sensitive tests and are widely used at well-equipped reference centers or central blood banks. Rapid tests are intended for qualitative detection of HBsAg in human serum, plasma, or whole blood wherever EIA methods are impractical or cannot be sustained. The majority of rapid tests currently marketed are based on agglutination or immunochromatographic principles. Rapid test kits usually contain all the supplies and reagents needed to perform a test. Earlier rapid and/or simple tests for HBsAg were developed in agglutination formats. One early rapid passive hemagglutination assay (RPHA), for example, utilized tanned red cells as a matrix. Such tests have filled a need for on-site testing, especially in developing countries, but RPHA sensitivity is relatively low (20-40 ng/ml sensitivity). The sensitivity of the more recently introduced immunochromatographic strip (ICS) tests, however, is somewhat better, and sensitivity limits of <1.0 ng HBsAg/ml have been reported. This may be compared to the sensitivity of a first-line EIA test for HBsAg where a sensitivity of 0.1-0.2 ng/ml is expected. The advantage of the ICS method, a one-step "walk-away" test, is that it can be completed in 10-20 minutes and performed by nurses or technicians with a minimum of training. It is practical for use at the provincial or peripheral health care level, since the strips are stable for one to two years at ambient temperatures, if packaged appropriately.