Diagnosis

Marker	Abbreviations	Purpose or uses	Technology
Hepatitis B surface antigen (qualitative)	HBsAG	Donor testing – screening of blood and tissue donations Diagnostic testing	Immunoassay Immunoassay Particle agglutination Rapid, short incubation assay including PoC
Hepatitis B surface antigen neutralisation	/	Confirmation of the presence of HBsAG	Immunoassay
Hepatitis B surface antigen (quantitative)	HBsAG	Monitoring of therapy	Immunoassay
Hepatitis B surface antibody	anti-HBs or HBsAb	Determining protective immunity*	Immunoassay
Hepatitis B core total antibody	anti-HBc or HBcT or HBcAb	As part of strategy to determine exposure to hepatitis B virus	Immunoassay
IgM to hepatitis B core antigen	IgM anti-HBc or HBcIgM	As part of strategy to diagnose acute hepatitis B infection	Immunoassay
Hepatitis B e antigen	HBeAg	Determining infectivity of a person with HBV infection and phase of the infection for clinical management	Immunoassay
Hepatitis B e antibody	Anti-HBe or HBeAb	Determining seroconversion from hepatitis B e antigen and phase of the infection for clinical management	Immunoassay

*anti-HBs levels fall over time and may become undetectable in people vaccinated years ago or in those who have cleared the virus. These individuals are still regarded as having acquired immunity. Where relevant, anti-HBc may provide evidence of past exposure when anti-HBs has become undetectable.

Interpretation of Results of Tests for Hepatitis B Virus Infection and Further Actions
HBsAg	Anti-HBs	Anti-HBc	Serology interpretation	Follow up
–	–	–	Susceptible to infection	Vaccinate
–	+	+	Immune due to past resolved infection	No further action required. Record result in file.
–	+	–	Immune due to vaccination	Record result. No need for further action.
+	–	+	Likely chronic infection	Manage as per guidelines for chronic hepatitis B

Serologic markers of HBv infection
Serologic marker	Description
HBsAg	• Protein on the surface of HBV • Can be detected at high levels in serum during acute HBV infection or in CHB • Presence indicates the patient is infected
Anti-HBs	• Antibody to HBsAg • Presence may indicate recovery and immunity from HBV infection • Also develops in patients successfully vaccinated against HBV
Total anti-HBc	• Antibody to core antigen of HBV (core antigen is not detectable in blood) • Appears at the onset of symptoms in acute HBV infection and remains throughout life • Presence indicates previous or ongoing HBV
IgM anti-HBc	• Immunoglobulin M class antibody to the core antigen of HBV • Presence indicates recent acute infection with HBV (≤6 months)
HBeAg	• Protein produced by the virus when it is actively replicating • Can be detected in serum during acute HBV infection and CHB • Some strains of HBV do not make e antigen • Presence indicates active replication
Anti-HBe	• Antibody to HBeAg • Presence indicates inactive infection except strains of HBV that do not make e antigen
HBV DNA	• Genetic material of HBV • Number of HBV DNA copies in the blood is used to detect active HBV infection and to monitor response to antiviral therapy (10,000 copies/mL = 2000 IU/mL)

Interpretation of Results of Tests for Hepatitis C Virus Infection and Further Actions
Test outcome	Interpretation	Further actions
HCV antibody nonreactive	No HCV antibody detected	Sample can be reported as nonreactive for HCV antibody. No further action required. If recent exposure in person tested is suspected, test for HCV RNA.*
HCV antibody reactive	Presumptive HCV infection	A repeatedly reactive result is consistent with current HCV infection, or past HCV infection that has resolved, or biologic false positivity for HCV antibody. Test for HCV RNA to identify current infection.
HCV antibody reactive, HCV RNA detected	Current HCV infection	Provide person tested with appropriate counseling and link person tested to care and treatment. †
HCV antibody reactive, HCV RNA not detected	No current HCV infection	No further action required in most cases. If distinction between true positivity and biologic false positivity for HCV antibody is desired, and if sample is repeatedly reactive in the initial test, test with another HCV antibody assay. In certain situations, § follow up with HCV RNA testing and appropriate counseling.

* If HCV RNA testing is not feasible and person tested is not immunocompromised, do follow-up testing for HCV antibody to demonstrate seroconversion. If the person tested is immunocompromised, consider testing for HCV RNA.

† It is recommended before initiating antiviral therapy to retest for HCV RNA in a subsequent blood sample to confirm HCV RNA positivity.

§ If the person tested is suspected of having HCV exposure within the past 6 months, or has clinical evidence of HCV disease, or if there is concern regarding the handling or storage of the test specimen.

Recommended Testing Sequence for Identifying Current Hepatitis C Virus (HCV) Infection