antibody - viral tests[1]

7/31/2019 Antibody - Viral Tests[1]

1/3

HBVHepatitis B Fact SheetHepatitis B Fact Sheet

a series of fact sheets written by experts in the field of liver disease

A Publication of the Hepatitis C Support Project

www.hbvadvocate.org

How to Interpret Hepatitis B

Antibody & Viral Tests

Written by: Chistine M. Kukka HBV Project Manager

To determine i someone is inected with the hepatitis B virus (HBV), or

to nd out the status o an inection, a clinician will take a blood sample

and send it to a laboratory. Technicians will analyze it or several hepatitis

B viral components, which provide a roadmap to an inection.

These viral components include antigens or proteins that make up dier-

nt parts o the virus and antibodies, which the immune system gener-

ates to combat each antigen. A viral test is dierent than a liver unction

est, which also requires a blood sample. Liver unction tests look at liver

nzymes, such as alanine aminotranserase or ALT, and other substances

hat may indicate i the liver is healthy or damaged.

Up to 70 percent o people inected with HBV, especially children, experi-nce no symptoms. The most common symptoms are jaundice (yellowing

the skin or the whites o the eyes), atigue, stomach discomort and ab-

dominal pain, ever, loss o appetite, nausea and joint pain.

Hepatitis B Antigens include:

Surface antigen:The outer coating o the virus is made up o the sur-

ace antigen or HBsAg. It surrounds the core o the virus.

Core antigen: The inner shell o a virus contains the core antigen (HB-

Ag). This antigen is only ound in inected liver cells.

E antigen: Another antigen ound in the cores interior is the e antigen

HBeAg).

To resolve or clear the HBV infection, the immune system must

produce antibodies against the HBV antigens certain proteins

of the hepatitis B virus.

HBV Genotype:

There are dierent strain

or genotypes o HBV

Each genotype originate

in dierent regions o th

world and is designate

by letters A-H. Doctor

dont routinely conduc

genotype tests, whic

require a blood sample

However, i pegylated in

tereron treatment is bein

considered, a doctor ma

order a genotype test be

cause genotypes A and B

appear to respond bette

to intereron than geno

types C and D.


2/3www.hbvadvocate.org

Hepatitis B Fact SheetHepatitis B Fact Sheet Fact SeriesHBV


Also within the core o the virus

are the viral DNA genetic mate-

ial and the DNA polymerase en-

zyme, which contains the key ge-

netic replication instructions.

n order to diagnose hepatitis B,

certain markers such as surace

antigens and antibodies, the e

antigens and antibodies, and core

antibodies are measured in a viral

est. Also, the levels o virus in the

blood (hepatitis B DNA or HBV

DNA) are measured to track how

actively viruses are replicating.

Hepatitis B surface antigen (HB-

sAg): The presence o surace

antigen in a lab report indicates

a hepatitis B inection. It can be

an acute (short-term) or a chronic

potentially lie-long) inection.

Simply put, i the surace antigen

s present, a person has HBV and

s capable o inecting others.

When HBV replicates in the liver,

t produces more surace antigen

han is needed to generate new

viruses. These excess surace

antigens clump together in the

bloodstream and are easily iden-

ed by lab tests. Laboratory

ests can usually identiy suraceantigen about our weeks ater in-

ection, but it can take as long as

nine weeks.

n an acute inection, the immune

system is able to combat the or-

eign surace antigen by creating

enough surace antibodies (ab-

breviated HBsAb or anti-HBsAg)

to destroy this antigen within a

ew weeks o when symptoms rst

appear. However, in a chronic in-

ection, the immune system can-

not eectively rid the body o the

antigen and create enough an-tibodies to ght o the inection.

Chronic hepatitis B is diagnosed

when surace antigen is present

in the bloodstream or more than

six months.

When surace antigens disappear

and surace antibodies appear in

a lab report, then a person has

cleared the inection. Bottom

line:the surface antibody is what

everyone wants to develop. It

means they have cleared the in-

fection and can no longer infect

others.

Hepatitis B Core Antigen (HB-

cAg) and Antibodies (anti-HBc

or HBcAb): The hepatitis B coreantigen orms the inner core o

the virus and is produced when

the virus replicates in liver cells.

The core antigen is ound only in

HBV-inected liver cells, not in the

bloodstream. But core antibodies

are ound in the bloodstream and

are identied by viral tests.

Core antibodies are the rst de-

tectable HBV antibodies to ap-

pear, usually within a ew weeks

ater inection. They are present in

anyone who has had either acute

or chronic HBV inection.

People who have been vaccinat-

ed against hepatitis B have been

injected with only the surace

tigen portion o the virus, to ca

their immune systems to prod

surace antibodies to pro

them against uture inection.

viral test on their blood would o

reveal the surace antibody. Hever, anyone who has been a

ally inected with HBV would h

core antibodies as well as sur

antibodies in their lab test.

Hepatitis B e Antigen (HBe

and e Antibodies (anti-Hbe

HBeAb): The e antigen is a

tein secreted by hepatitis B vi

es that are actively replicatingliver cells. When a lab test ide

es the e antigen, it means

virus is actively replicating and

person usually has a large qua

o HBV-DNA in their bloodstre

Their blood and body fuids

usually more inectious, beca

o the high volume o virus, t

someone who has developed

e antibody.

People with the e antigen m

be at greater risk o progress

to liver disease than those w

have developed the e antibo

especially ater many years

inection, because it indica

rapid viral replication. Child

with chronic hepatitis B otest positive or the e anti

because their immune syste

have not yet noticed the viru

attacked the inected liver ce

Some people who have had h

atitis B or many years lose the


3/3

2010 Hepatitis C Support Pro

www.hbvadvocate.org

The inormation in this act sheet is designed to help you understand and man-

age HBV and is not intended as medical advice. All persons with HBV should

consult a medical practitioner or diagnosis and treatment o HBV.

Executive Director,Editor-in-Chief, HCSP Publications

Alan Franciscus

Managing Editor / WebmasterC.D. Mazoff, PhD

This inormation is provided by the Hepatitis C Support Project a nonproft organization or HCV education, support and advocacy.

Reprint permission is granted and encouraged with credit to the Hepatitis C Support Project.

Hepatitis B Fact SheetHepatitis B Fact Sheet Fact SeriesHBV

For more inormation about hepatitis B, visit the ollowing websites.

Hepatitis B Foundation: www.hepb.org HIVandHepatitis.com

HCSP VERSION 3.0 September 20

antigen, developeantibodies,

but continue to have moderate-

y high viral load and elevated

ALT levels, which indicates liver

damage. This HBeAg-nega-

ive hepatitis is believed to be

caused by HBV that have cer-

ain mutations (a precore mu-

ation), which allow the virus to

eplicate without producing the

e antigen.

n acute hepatitis B, when the

bodys immune system quickly

esponds and eradicates theantigens and inected liver

cells, the e antigen appears

only briely. It disappears as

viral replication declines in the

ver and the immune system

produces e antibodies to de-

stroy this antigen.

Hepatitis B e antibodies usu-

ally persist or one or more years

ater resolution o an acute in-

ection. Seroconversion, or

production o e antibodies, is

one o the goals o most medi-

cal treatments or hepatitis B.

Once e antibodies are pro-

duced, there are usually ewer

HBV inecting and damaging

he liver.


Hepatitis B Virus DNA (HBV

DNA): HBV DNA is the genetic

material that carries the blue-

print o the virus. It is ound in

the bloodstream and is the best

indication o how rapidly thevirus is replicating in the liver.

High levels o HBV-DNA, which

can reach up to millions or bil-

lions o international units per

milliliter (abbreviated copies/

mL), indicate rapid viral replica-

tion in the liver and a higher risk

o liver damage. Low or unde-

tectable rates indicate low viral

replication in the liver.

Because viral load can be very

high, viral load can be reported

in logs that represent multi-

plying the number by 10, so 101

equals 10, 102 equals 100, and

103 equals 1,000 etc. A v

load that appears as 104 c

ies/mL equals 10,000 cop

mL.

Doctors should always tespatients viral load becaus

plays an important role in

ciding i someone needs tre

ment, or i treatment is work

to lower viral load. For ex

ple, current guidelines sugg

that people who test positive

HBeAg, have elevated ALT

els that indicate liver dama

and who have a viral load ab

20,000 IU/mL may be con

ered or treatment. Peo

who are HBeAg-negative w

elevated ALTs, and who h

viral load exceeding 2,000

mL may also be considered

treatment.

Some people who have

had hepatitis B for many

years lose the e antigen,

developeantibodies, but

continue to have moderately

high viral load and elevated

ALT levels, which indicates

liver damage.

antibody - viral tests[1]

Documents