Serology: Suitable specimens are individual samples (human sera or EDTA/heparinized/citrated plasma) obtained by standard laboratory techniques.

Specimen Minimum Volume

0.6ml

Transport Temperature

*The samples should be stored for not more than 3 days at 2-8^°C.

**For longer delay, freeze at -70^°C and transport on dry ice.

Reject Due To

Useful For

Anti-HAV IgM is useful for the serological diagnosis of acute-phase Hepatitis A virus (HAV) infection. Anti-HAV IgG is an indicator of successful HAV vaccination or indicator of prior HAV exposure.

Clinical Information

Hepatitis A characteristically is an acute, self-limited illness associated with fever, malaise, jaundice, anorexia, and nausea. Among older children and adults, infection usually is symptomatic and typically lasts several weeks, with jaundice occurring in 70% or more. Symptomatic infection occurs in approximately 30% of infected children younger than 6 years of age; few of these children will have jaundice. Fulminate hepatitis is rare but is more common in people with underlying liver disease. Chronic infection does not occur.

Serological diagnosis of acute viral hepatitis A depends on the detection of specific anti-HAV IgM. Its presence in the patient’s serum indicates a recent exposure to HAV. Anti-HAV IgM becomes detectable in the blood within 2 weeks after infection, persisting at elevated levels for about 2 months before declining to undetectable levels by 6 months. However, sensitive immunoassays may occasionally detect anti-HAV IgM for up to 1 year after acute hepatitis A.

Hepatitis A virus (HAV) is endemic throughout the world, occurring most commonly in areas of poor hygiene and low socioeconomic conditions. The virus is transmitted by the fecal-oral route, and it is spread by close person-to-person contact and by contaminated food and water. Thorough cooking is necessary to inactivate HAV in contaminated foods. Outbreaks frequently occur in overcrowded situations and in high-density institutions and centers, such as prisons and health care or day care centers. Viral spread by parenteral routes (eg, exposure to blood) is possible but rare, because infected individuals are viremic for a short period of time (usually <3 weeks). There is little or no evidence of transplacental transmission from mother to fetus or transmission to newborn during delivery.

HAV is a nonenveloped, positive-strand RNA virus of the Picornaviridae family, which includes the enteroviruses, parechoviruses, and rhinoviruses of humans, as well as the apthoviruses or hoofed animals and cardioviruses of mice. Although HAV shares general structure and genomic organization with the other picornaviruses, it has limited nucleotide sequence homology and distinguishing characteristics that have resulted in its being classified in its own genus, Hepatovirus.

Reference Values

Anti-HAV IgG

NONREACTIVE

Anti-HAV IgM

NONREACTIVE

Interpretation

Clinical Reference

Abbott. 2004. ARCHITECT System HAVAb-IgG: package insert. Abbott Diagnostics Division, Wiesbaden, Germany.

Abbott. 2004. ARCHITECT System HAVAb-IgM: package insert. Abbott Diagnostics Division, Wiesbaden, Germany.

Anderson, D. A. 2007. Hepatitis A and E Viruses, p. 1424-1436. In Murray, P. R., Baron, E. J., Jorgensen, J. H., Landry, M. L., and Pfaller, M. A. Manual of Clinical Microbiology, 9^th ed., vol. 2. ASM Press, American Society for Microbiology, Washington, DC.

Wasley, A., Feinstone, S. M, and Bell, B. P. 2010. Hepatitis A Virus, p. 2367-2387. In Mandell, D., Bennett, J. E., and Dolin, R. Principles and practice of infectious diseases, 7^th ed., vol. 2. Churchill Livingstone, Elsevier, Philadelphia, PA.

Method Description

Enzyme-linked immunosorbent assay (ELISA)

Performing Laboratory Location

Newfoundland & Labrador Public Health Laboratory

St. John’s