Hepatitis virus serology

How the Test is Performed:
Adult or child:
Blood is drawn from a vein ( venipuncture ), usually from the inside of the elbow or the back of the hand. The puncture site is cleaned with antiseptic, and a tourniquet (an elastic band) or blood pressure cuff is placed around the upper arm to apply pressure and restrict blood flow through the vein. This causes veins below the tourniquet to distend (fill with blood). A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. During the procedure, the tourniquet is removed to restore circulation. Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding .

Infant or young child:
The area is cleansed with antiseptic and punctured with a sharp needle or a lancet. The blood may be collected in a pipette (small glass tube), on a slide, onto a test strip, or into a small container. Cotton or a bandage may be applied to the puncture site if there is any continued bleeding.

How it Feels:
When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing .

Risks:
  • excessive bleeding
  • fainting or feeling lightheaded
  • hematoma (blood accumulating under the skin)
  • infection (a slight risk any time the skin is broken)
  • multiple punctures to locate veins



Why this Test is Performed:
This test is performed to detect hepatitis . Hepatitis is an inflammation of the liver caused by a virus. Three common hepatitis viruses are recognized: hepatitis A , hepatitis B , and hepatitis C (C is also called non-A , non-B).

Infection with hepatitis A virus (HAV) was originally called infectious hepatitis, but this terminology is inaccurate. HAV has a short incubation period of 2 to 6 weeks; it is excreted in the stool and transmitted via the fecal-oral route.

Infection with HBV was originally called serum hepatitis, but this terminology is no longer used. HBV has a long incubation period (that is, 5 weeks to 6 months). It is most frequently transmitted by blood transfusion, but can also be contracted through other body fluids. HBV may cause a severe and unrelenting form of hepatitis ending in liver failure and death. The incidence of HBV is increased among blood transfusion recipients, male homosexuals, dialysis patients, transplant patients, IV drug users, and individuals with leukemia or lymphoma .

The HBV, also called the Dane particle, is made up of an inner core surrounded by an outer capsule. The outer capsule contains the HBsAg (surface antigen ). The inner core contains HBcAg (core antigen). HBeAg is also found within the core. The antibodies produced against these antigens are called HBsAb, HBcAb, and HBeAb.

Hepatitis C is transmitted in a manner similar to HBV. The incubation period is 2 to 12 weeks after exposure. The clinical manifestations of the illness parallel those of HBV. Most patients with hepatitis caused by blood transfusions have hepatitis C.

Normal Values:
No presence of antibodies (a negative test) is normal.

Abnormal Results:
Serology tests have been developed to detect the presence of each of the hepatitis viruses in serum, but the virus may be present in the liver without being detectable in serum.

There are also tests designed to measure the presence of antibodies to HAV and HBV in serum, which then is taken as evidence of infection by these viruses. (Note: antibodies, or immunoglobulins, are grouped according to type. Common groups include IgM , IgA , IgG , IgE. See immunoelectrophoresis - serum ). IgM antibodies appear 3 to 4 weeks, after exposure and usually return to normal in about 8 weeks. IgG antibodies appear about 2 weeks after the IgM antibodies start to increase; such antibodies may persist for as long as 10 years. If the IgM antibody is elevated in the absence of IgG antibody, acute hepatitis is suspected. If IgG antibody is increased, but not IgM antibody, a convalescent or chronic state is likely.

Positive tests may indicate:

Additional conditions under which the test may be performed:



Cost:
The costs are:
$66 for a hepatitis B surface antigen test
$98 for an anti HCV test
$105 for a hepatitis A & B panel
$196 for a serial Anti-HCV test

Special Considerations:
Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.


Hepatitis A is called infectious hepatitis and is spread by fecal contamination. The virus appears in the stool of infected individuals and is spread when hygiene practices are inadequate. Hepatitis A is frequently seen in mini-epidemics in day-care settings and institutional settings. This photograph is an electronmicroscopic image of hepatitis A virus particles. (Courtesy of the Centers for Disease Control.)



Hepatitis B is also known as serum hepatitis and is spread through blood and sexual contact. It is seen with increased frequency among intravenous drug users who share needles and among the homosexual population. This photograph is an electronmicroscopic image of hepatitis B virus particles. (Courtesy of the Centers for Disease Control.)



This early (1950s) poster was designed to warn the public about infectious hepatitis (hepatitis A). Today's public is considered better informed and is given more sophisticated information. (Courtesy of the Centers for Disease Control.)



This person has a yellowish cast to the skin (jaundiced). (Courtesy of the Centers for Disease Control.)



Erythema multiforme - close-up of the hands: These lesions are circular and may appear in concentric rings (often called target lesions). They may be associated with other medical conditions such as the herpes infection, streptococcal infection, tuberculosis (TB), or as a reaction to chemicals or medications.



Erythema multiforme lesions are circular and may appear in concentric rings (often called target lesions). Target lesions may also be associated with other medical conditions such as herpes infection, streptococcal infection, tuberculosis (TB), or as a reaction to chemicals or medications.



Erythema multiforme lesions are circular and may appear in concentric rings (often called target lesions). When erythema multiforme affects the mouth and mucous membranes, it is called erythema multiforme major or Steven's Johnson Syndrome.