May is Hepatitis Awareness Month in the United States, and the CDC is hoping to bring attention to the importance of medical screening for the most common forms of viral hepatitis: Hepatitis A (HAV), which is generally an acute infection, and Hepatitis B (HBV) and Hepatitis C (HCV), which are chronic infections. These laboratory tests fall under the subspecialty of General Immunology, and are used to detect either viral antigens or serum antibodies against those antigens. Testing for both antigens and antibodies can help to narrow down whether there is an active or chronic infection, and distinguish between vaccine-induced immunity and antibodies that were generated after an active infection.
Most common hepatitis laboratory tests
|Hepatitis B Surface Antigen||HBsAg||Can indicate current HBV infection|
|Hepatitis B Surface Antibody||HBsAb||Can indicate immunity (or past infection if HBcAb also positive)|
|Hepatitis B Core Antibody||HBcAb||Can indicate past infection|
|Hepatitis C Antibody||Anti-HCV|
|Can indicate exposure to HCV, needs confirmatory testing|
|Hepatitis C RNA||Can be qualitative or quantitative, measures current viral load to indicate active infection. Also used to monitor treatment|
|Hepatitis A Antibody||Anti-HAV|
|Can indicate immunity or past infection (IgG)|
Can indicate current infection (IgM)
Fortunately, there are safe and effective vaccines available to protect people from infection with the hepatitis A and hepatitis B viruses. Hepatitis A vaccinations are often recommended before travel to areas where there is a high risk of acquiring HAV infection from the local water or food supply. Hepatitis B vaccinations are now standard childhood vaccinations, and they are also offered to laboratory and other healthcare workers who risk being exposed to blood and body fluids on the job. Unfortunately, there is no vaccine yet available to prevent hepatitis C, which is also transmitted by blood and body fluids. Hepatitis C infection remains a serious chronic problem in the United States.
Chronic hepatitis C infection is one of the leading causes of liver cancer and liver transplants in the United States. Unfortunately, many individuals infected with the hepatitis C virus are asymptomatic for decades after their exposure to the virus, and are unaware of their higher risk for liver disease. The CDC estimates that approximately 75% of the 3.2 million Americans infected with hepatitis C are members of the “Baby Boomer” generation, born between 1945 and 1965. The CDC has recommended that all individuals born during that era be tested for chronic hepatitis C.
A preliminary screening test for hepatitis C is detects Anti-HCV antibodies in the patient’s serum, which would indicate that they’ve been exposed to the virus. When a screening test result is positive, the follow-up looks for viral DNA or RNA, to see whether the virus is present, active, and replicating within the patient’s body. The CDC recommends that anyone who tests positive for Hepatitis C infection should be counseled about alcohol use, since excessive alcohol intake can hasten the liver damage that comes along with hepatitis C. Knowing the patient is at higher risk for liver damage means that the patient and their physician can make better decisions about medication use – many drugs, even over-the-counter ones like acetaminophen, can stress the liver.
While there’s no vaccine for hepatitis C, it’s highly recommended by the CDC and medical professionals that everyone be vaccinated against the entirely preventable hepatitis B virus. Especially for a laboratory professional, whose daily work brings them into contact with blood and contaminated body fluids, there’s really no reason to put your liver at risk.