How much HBsAg is normal?

The article is professionally consulted by MSc Tran Thi Vuong - Doctor of Microbiology, Laboratory Department - Vinmec Hai Phong International General Hospital.

HBsAg index is valuable used to classify, monitor treatment and prognosis of hepatitis B patients. The HbsAg test is a test to diagnose whether a patient is infected with hepatitis B virus or not. .

HbsAg is an acronym for Hepatitis B surface antigen, which is the surface antigen of the hepatitis B virus. If HbsAg is positive (HbsAg+), the patient has HbsAg in the blood, it means there is HBV virus in the blood.
Conversely, if HBsAg is negative (HbsAg-), the patient does not have HBV virus in the blood. Normally, HBsAg appears in the blood 1 to 8 weeks after the body is exposed to the HBV virus.
The HBsAg index is an indicator of the surface antigen of the B virus. To check if the patient is infected with the hepatitis B virus, it is not used to accurately assess the virus that is active. in the patient's body.
Experts say most patients with acute hepatitis B test positive for HbsAg. After a variable period of time, HBsAg will disappear and anti-HBs will stop the infection, but about 10%-15% turn to the chronic stage and lead to cirrhosis and cancer. liver.

If you do an automated immunoglobulin HBsAg test: that is, run the test on an automated system, then the machine will usually return a numerical result. Values ​​that exceed the reaction threshold will be interpreted as Positive. Values ​​below the response threshold will be considered negative. Most automated machines with different chemical brands are setting 1.0 SO or COI as the cutoff value. Thus, a test result less than 1.0 SO or COI (<1.0) is a normal value - a negative value. A larger test result (>1.0 COI or SO) is positive.

If the HBsAg index is normal, it means that the person has not been infected with hepatitis B. If the test is negative for HBsAg surface antibodies, the hepatitis B vaccine should be vaccinated. Anti-HBsAg positive means that the person is already immune to hepatitis B virus or has been infected with hepatitis B virus in the past and has completely recovered.
In case the result is positive, to decide whether to treat or not, it is necessary to do other tests such as: HBeAg, HBV-DNA, liver function, liver ultrasound... Patients need to be consulted by a specialist for effective treatment and monitoring.

Some issues that need special attention are as follows:
Many cases give a positive HBsAg test result that does not accurately confirm that they have the disease. According to experts, HBsAg test results (+) are very common in people in the country, on average, for every 10 people blood tests, there are 2 people with HBsAg (+) results. If the HBsAg test is positive, the first thing you should do is go home and encourage your family members to get tested to see if anyone else has the disease. In case the pregnant mother is infected with hepatitis B virus, the baby must be vaccinated within the first 12 hours after birth and the mother must absolutely not breastfeed because the virus will be transmitted through the mother. feed the baby with breast milk. Relatives should not share personal items with the sick person to avoid infection such as toothbrushes, towels, razors, bathtubs, etc. Patients should tell their partners about their illness. and do not absolutely not have sex without safety measures.