The detection of B19 is based on nucleic acid hybridization assays. Mainly ‘Dot Blot Hybridization’ and ‘In-Situ Hybridization’ have been used for detection of B19 within bone marrow and other cells. In healthy immunocompetent individuals, infection can be detected for 2-4 days by ‘Dot Blot Hybridization’ based on IgM assays ideally performed by the capture technique. In RIA or ELISA, antibody is detected by approximately 3-5 day of infection and remains detectable for 2-3 months. However, these techniques face with quite critical drawbacks even though being easy and quick techniques. Cross–reaction of antibodies or rheumatoid factor may result in false positive results and moreover, since the immunocompromised patients may not mount an immune response, these techniques based on antibody detection are not helpful and make it vital to test B19 antigens or nucleic acid (DNA).
The use of PCR both overcomes the drawbacks of antibody tests and also increases the analytical sensitivity. It is more practical, fast and reliable solution.