As previously mentioned, hepatitis symptoms can be nonspecific. Laboratory testing for specific viral antibodies plays an important role in assessing whether hepatitis symptoms are due to viral versus non-viral causes. However, other non-serologic laboratory tests are also vital in the workup of hepatitis. For example, a total bilirubin of 3.0 mg/dL or higher and an alanine aminotransferase (ALT) greater than 200 IU/L are both strongly associated with hepatitis. These two common laboratory tests are part of the standard 'comprehensive metabolic panel' (CMP). The CMP is the third most commonly-ordered panel in medicine (after the complete blood count and the basic metabolic panel).
While this course will concentrate specifically on viral markers of hepatitis, it is important to mention that other clinical chemistry tests provide needed information for the hepatitis patient. The chemistry tests below all function as liver function tests (LFTs). Some are liver enzymes, others (such as albumin and prothrombin time) are circulating proteins that are made in the liver and thus serve a markers of liver function in that, if low, they reveal inadequate production due to a damaged liver.
Liver Function Tests:
- Total bilirubin
- Direct/Indirect Bilirubin
- Alanine aminotransferase (ALT)
- Aspartate aminotransferase (AST)
- Lactate dehydrogenase (LD)
- Alkaline phosphatase (ALK or AP)
- Albumin
- Clotting tests (PT/aPTT, INR, fibrinogen, etc.)
- Total protein
