Is HBV DNA Quantitative Test 8 Days Post Exposure Conclusive?

Posted on Sun, 14 Aug 2016

Medically reviewed by Ask A Doctor - 24x7 Medical Review Team

Sun, 14 Aug 2016 Answered on

Wed, 31 Aug 2016 Last reviewed on

Question : Hi...I had HBV DNA PCR test done 8 days post exposure and came back non-reactive undetecrable, how accurate is that result?
And normally what is the earliest most accurate post exposure days before doing that test?

Answered by Dr. Priyanka G Raj (6 hours later)

Brief Answer:
repeat test after 1-2 months

Detailed Answer:
Hi
Thanks for the query
This test is used to look for the presence of Hepatitis B (Hep B) viral genetic material in the blood. The results for this test are quantitative, meaning they provide a numerical result rather than a simple positive or negative. Because Viral DNA is often detectable sooner than antibodies developed in response to an infection
The presence of HBV DNA in serum is a reliable marker of active HBV replication.
HBV DNA levels are detectable by 30 days following infection.

The Hep B PCR test can typically detect the virus 3 weeks from exposure

So you had get it done after 8 days of exposure and it is showing negative.So this test is not reliable because the incubation period for HBV infection is 30 - 40 days. ie it takes nearly so much of time to infect the person . so you need to get it done again after 1 month.

This test is done maily for viral load and for screening. After 1 month you can get done HBSAg and HBEAg, which gives equivocal results.
If you have any doubt you are welcome.

Regards
Dr Priyanka G Raj

Above answer was peer-reviewed by : Dr. Priyanka G Raj