An anti-HEV IgM test is used to detect the presence of Hepatitis E virus (HEV) in the blood. A positive IgM test result suggests an active, acute or recent (within the last 6 months) HAV infection. IgM antibodies develop 2 weeks after a person is infected. It could also indicate a past HAV vaccination. Both IgM and IgG antibodies to HEV are produced following infection. The titer of IgM anti-HEV declines rapidly during early convalescence