FaridabadBy Dr B.C. Gupta, MD · 2026-10-15
Ask the Pathologist - MCQ of the Week. A short question to test how well you know common laboratory tests, with a plain-English explanation from Dr B.C. Gupta, MD (Pathology).
Q. Which laboratory test is used to screen for current hepatitis B infection?
- A. Hepatitis B surface antigen (HBsAg)
- B. Dengue NS1
- C. HbA1c
- D. Thyroid profile
Answer: Hepatitis B surface antigen (HBsAg)
HBsAg, the hepatitis B surface antigen, is the test used to screen for current hepatitis B infection. It detects a protein on the surface of the virus itself, so a positive result means the virus is present in the blood and can be passed on to others. It is the first test a doctor usually orders when hepatitis B is suspected or when screening is being done before surgery or during pregnancy.
The hepatitis C antibody test, written as anti-HCV, does something similar for hepatitis C, but it works differently. Antibodies show that a person has been exposed to a virus, not necessarily that the infection is still active, so a positive antibody result is normally followed by a test that looks for the virus directly. That is why hepatitis B and hepatitis C screening use different first-line tests.
Dengue NS1, HbA1c and a thyroid profile do not detect hepatitis at all. Dengue NS1 is used when dengue is suspected, HbA1c reflects average blood sugar over about three months, and a thyroid profile checks hormone levels. If your doctor has asked for a hepatitis B or hepatitis C test, call the centre to confirm preparation and timing before you visit.
