Screening For Hepatitis B, Hepatitis C & HIV in A Patient With Past History of Drug Abuse...

A 23-yr-old with a history of intravenous drug abuse in the past is seen in the medical out patient's clinic following DVT 2 moths ago for which he is on warfarin therapy.
He has the following blood results:
U&E, normal;
Albumin, 39 g/l;
ALT, 170 U/l;
GGT, 20 U/l;
LDH, 500 U/l;
Bilirubin, 23 μmol/l;
INR, 2.5;
Hb, 13.3 g/dl;
WCC, 4.2 x 109/l;
Platelets, 300 x 106/l.
You suggest that he should be screened for hepatitis B and C and HIV.
The results subsequently come back as follows:
HIV-1 and -2 antibody tests, negative;
Hepatitis B core IgG, positive;
Hepatitis B surface antigen, positive;
Hepatitis B e antigen, negative;
Hepatitis C IgG and PCR, negative.

Which test is most likely to lead to the correct diagnosis?

A. Hepatitis B DNA
B. Hepatitis D test
C. VDRL
D. AFP
E. Hepatitis E test

Answer:
A. Hepatitis B DNA

Discussion: The Pt is quite likely to have the Precore Mutant Form of Hepatitis B. This is hepatitis B,
which, although replicating actively, does not produce e antigen, either as a result of a mutation in the gene producing e antigen itself or as a result of a mutation in one of the gene upregulators.
Hepatitis B DNA can be measured quantitatively, and a high level in this patient would be suggestive of precore mutant hepatitis B.