Elecsys^® Anti-HAV II

Immunoassay for the qualitative detection of total antibodies against HAV

Immunoassay for the qualitative detection of total antibodies against HAV

Elecsys^® Anti-HAV II is an immunoassay for the in vitro qualitative detection of total (IgM and IgG) antibodies to HAV in human serum and plasma. It is used as an aid to detect a past or existing HAV infection or to determine the presence of antibody response to HAV in vaccine recipients.¹¹

Hepatitis A

Hepatitis A is an acute, inflammatory liver disease caused by infection with the hepatitis A virus (HAV). HAV is a non-enveloped RNA virus in the family of picornaviruses. Of the 7 known genotypes, 4 can infect humans. Only one serotype of HAV has been documented.^1-5

Hepatitis A occurs sporadically and in epidemics worldwide, with around 1.4 million new HAV infections reported each year.^3,4 HAV is transmitted fecal-orally either by person-to-person contact or ingestion of contaminated food or water in regions of low hygienic standards. Cooked foods can transmit HAV if the temperature during food preparation is inadequate to inactivate the virus or if food is contaminated through infected food handlers.^1,4-6

HAV has only been linked with acute hepatitis, and most patients fully recover within two months after infection. Only 10 - 15 % of people infected will have prolonged or relapsed illness for up to 6 months. Exposure to HAV creates lifelong immunity against future infection. HAV vaccines are available, which also stimulate active, lifelong immunity with 95 – 100 % efficiency.^1-4

Anti-HAV IgM becomes detectable 5 - 10 days before onset of symptoms, peaks during the symptomatic period and becomes undetectable in 75 % of patients 3 - 6 months after infection. Anti-HAV IgG, which appears after IgM, begins to rise at or right before the onset of clinical illness, peaks during the convalescent period, and persists to provide lifelong protection against the disease.^3,7-10

Proposed algorithms for diagnosis of HAV infection

Unkown HAV immune status

The patient may have an acute or past HAV infection, or may not be immune
Initial test – anti-HAV (total assay)

With this algorithm, all three possible outcomes can be identified by testing first with the anti-HAV (total) assay followed by the anti-HAV IgM assay if necessary. By contrast, an HAV IgG assay alone cannot identify or exclude acute infection; an HAV IgM test is also required.^10,13

Suspected acute HAV infection

The patient is exhibiting clinical symptoms
Initial test – anti-HAV IgM assay

With this algorithm, all three possible outcomes can be clearly identified by testing first with the anti-HAV IgM assay followed by the anti-HAV (total) assay if necessary.^10,13,14

Marker profile

Hepatitis A infection marker profile after natural infection^3,7-10,12

* ALT = alanine aminotransferase

Hepatitis A infection: marker profile after natural infection3,7-10,12

* ALT = alanine aminotransferase

References

Cuthbert, J.A. (2001). Hepatitis A: old and new. Clin Microbiol Rev 14(1), 38-58.
Lemon, S.M. et al. (2018). Type A viral hepatitis: A summary and update on the molecular virology, epidemiology, pathogenesis and prevention. J Hepatol 68, 167-184.
Pischke, S., Wedemeyer, H. (2018). Hepatitis A In: Mauss, S. et al. Hepatology. A Clinical Textbook. Ninth Edition. Available from: https://www.hepatologytextbook.com/. [Accessed: May 11, 2020].
World Health Organization (WHO) (2019). Hepatitis A Factsheet. Available from: https://www.who.int/news-room/fact-sheets/detail/hepatitis-a.
Yong, H.T., Son, R. (2009). Hepatitis A virus - a general overview. Int Food Res J 16, 455-467.
Centers for Disease Control and Prevention (CDC) (2016). Hepatitis A – Questions and Answers for Health Professionals. Available from: https://www.cdc.gov/hepatitis/hav/havfaq.htm [Accessed: May 06, 2020].
Hollinger, F.B., Emerson, S.U. (2007). Hepatitis A virus. In: Fields Virology, Knipe OM, Howley PM (eds), 5th edition, Lippincott Williams and Wilkins, Philadelphia, USA Chapter 27, pp. 911-947.
Stapleton, J.T. (1995). Host Immune Response to Hepatitis A Virus. J Inf Dis 171(suppl 1), 89-14.
Roque-Afonso, A.M. et al. (2010). Hepatitis A virus: serology and molecular diagnostics. Future Virol 5(2), 233-242.
Salete de Paula,V. (2012). Laboratory diagnosis of hepatitis A. Future Virol 7(5), 461-472.
Elecsys® Anti-HAV II method sheet, V2.0 2019-11.
Centers for Disease Control and Prevention. Viral Hepatitis Serology Training, Hepatitis A (2015). Available at: https://www.cdc.gov/hepatitis/resources/professionals/training/serology/training.htm. [Accessed: May 06, 2020].
Gilson, R. and Brook, M.G. (2006). Hepatitis A, B, and C. Sex Transm Infect. 82(Suppl 4), iv35-iv39.
UK Standards for Microbiology Investigations. (2019). Hepatitis A Virus Acute Infection Serology. Issued by the Standards Unit, Microbiology Services, PHE Virology 27(4). Available at: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/772178/V_27i4.pdf [Accessed: June 02, 2020].