From the Guidelines
To diagnose hepatitis B, you should order a hepatitis B panel, which includes several blood tests that detect different markers of the virus, with the HBsAg test being particularly important as it indicates active infection when positive, as recommended by the most recent guidelines 1. The hepatitis B panel typically consists of hepatitis B surface antigen (HBsAg), hepatitis B surface antibody (anti-HBs), hepatitis B core antibody (anti-HBc), hepatitis B e antigen (HBeAg), and hepatitis B e antibody (anti-HBe).
- The HBsAg test is used to diagnose acute or chronic hepatitis B infection.
- The anti-HBs test is used to determine if a person has immunity to hepatitis B, either from vaccination or from a past infection.
- The anti-HBc test is used to determine if a person has had a past infection with hepatitis B.
- The HBeAg and anti-HBe tests are used to determine the level of viral replication and to guide treatment decisions. If HBsAg is positive, additional testing for HBV DNA viral load can help determine the level of viral replication and guide treatment decisions, as suggested by 1 and 1. Liver function tests such as ALT and AST should also be ordered to assess liver damage, as recommended by 1 and 1. These tests collectively help determine if a person has acute or chronic hepatitis B infection, has recovered from a past infection, or has immunity from vaccination. Early diagnosis is crucial because chronic hepatitis B can lead to serious liver complications including cirrhosis and hepatocellular carcinoma if left untreated, as highlighted by 1 and 1. It's worth noting that the most recent and highest quality study 1 provides the most up-to-date recommendations for the diagnosis and management of hepatitis B, and should be prioritized when making clinical decisions.
From the Research
Diagnosis of Hepatitis B
To diagnose hepatitis B, the following tests can be ordered:
- Hepatitis B surface antigen (HBsAg) test: This is the hallmark of HBV infection and is the first serological marker to appear in acute hepatitis B 2.
- Hepatitis B e antigen (HBeAg) test: This usually indicates active HBV replication and risk of transmission of infection 2.
- Hepatitis B DNA test: This is valuable for assessing liver disease activity, differentiating other etiologies of hepatitis activity in HBV carriers, predicting risk of HCC development or liver-related mortality, deciding to administer antiviral therapy, determination of the response to antiviral treatment, predicting the risk of developing drug resistance, and detecting the emergence of drug-resistant mutants 2.
- Rapid diagnostic tests (RDTs) for HBsAg detection: These tests are simple, fast, and cheap, and can be used for large-scale screening and diagnosis of HBV infection in the clinical setting 3.
Test Selection
The selection of tests may depend on the clinical presentation and the stage of the disease. For example:
- In acute hepatitis B, HBsAg is the first serological marker to appear 2.
- In chronic HBV infection, HBsAg persistence for more than 6 months suggests chronic infection 2.
- In cases of fulminant hepatitis, the detection of HBsAg and antibodies to the surface and core antigens of the hepatitis B virus (anti-HBS and anti-HBC) can be useful in diagnosis and prognosis 4.
Assay Comparison
Different assays are available for the detection of HBsAg, and their sensitivity and specificity may vary:
- A comparison of two techniques for detecting antibody to HBsAg found that a direct sandwich radioimmunoassay (RIA) and an inhibition enzyme-linked immunosorbent assay (ELISA) showed full agreement for anti-HBs in sera containing more than 10 IU/l anti-HBs 5.
- A study comparing five assays for the detection of HBsAg found that the IMx HBsAg V2 assay showed the highest sensitivity, and outperformed other assays in analytical sensitivity and in detection of HBsAg mutants 6.