Exams and Tests
A thorough medical history and physical examination provide
valuable information about your symptoms and whether it is likely that you have
been exposed to the
hepatitis A virus (HAV).
While taking a medical history, your health professional usually
will ask where you have traveled, if you work in or have a child in a day care
center, and if you live with someone known to have hepatitis A.
If you may have been exposed to hepatitis A, you will have blood
tests to study liver function and to see whether your liver is damaged or
inflamed. Blood tests to study liver function include:
- Bilirubin. When bilirubin builds up in
the blood, it may indicate hepatitis.
- Albumin.
Lower than normal levels may indicate hepatitis or other liver
problems.
- Prothrombin time, a blood test that
measures how long it takes blood to clot. An abnormal prothrombin time can be
caused by liver disease or injury.
Blood tests that may be done to determine whether the liver is
damaged or inflamed include:
- Alanine
aminotransferase (ALT). When the liver is damaged or diseased, ALT is
released into the bloodstream, causing levels of the enzyme to
rise.
- Aspartate aminotransferase (AST). When
body tissues or organs such as the heart or liver are damaged, AST is released
into the bloodstream. The amount of AST in the blood is directly related to the
extent of the tissue damage.
- Alkaline phosphatase
(ALP). Large amounts of ALP in the bloodstream may indicate liver
damage.
- Lactic dehydrogenase (LDH). Many diseases can cause
elevations in LDH levels. In addition to the LDH test, your doctor will usually
run other tests to confirm a diagnosis of hepatitis A.
If tests show your liver is inflamed, you will have an
antibody (anti-HAV) test on a sample of your blood.
The presence of HAV antibodies means that HAV infection is the most likely
cause of your hepatitis.
If the results of the anti-HAV test show that HAV is not
multiplying in your body, your doctor may do other hepatitis blood tests to
find out whether
hepatitis B virus,
hepatitis C virus, or
Epstein-Barr virus (which causes infectious
mononucleosis, or “mono”) is causing your hepatitis.
Early Detection
If you are concerned that you have been exposed to the virus and
you have not been previously infected or vaccinated, contact your health
professional. If you get a shot of
immune globulin (IG) within 2 weeks of being exposed
to HAV, you probably will not develop symptoms of HAV infection.
Routine vaccination of hospital workers, food handlers, and child
care center workers and attendees does not occur at this time because their
chance of infection generally is no greater than that of the wider community.
But some child care centers have workers get the shot because it works so well
to prevent the disease. Plus there is very low chance of side effects from the
vaccine. If outbreaks of HAV infection do occur in those settings, people who
were exposed to the virus should receive a shot of immune globulin
(IG).4