as pcr is usually done for detecting viremia and as it is well known that when virus replicates so it is in blood circulation and at this stage an antigen can be detected. as HBV is detected through direct Elisa that is antigen is directly detected. we usually detect antigen through pcr. then why need for pcr?
so any usfeull comments plz
Dear Sajid,
We need PCR for the quantification of hepatitis B. For the treatment of hepatitis B viral quantity is very important.@Sajid Ali
Dear my question is same that ye for treatment intake we do quantitative pcr but initially when diagnosed HBsAg on ELISA based which is direct elisa means AG is present in the blood then why need of pcr as it is not necessary that for all HBsAg positive patients PCR will also be reactive, so here the problem occur. at this stage what comments will be useful?
Indeed, Sajid, I also can not explain why it would be necessary to do PCR before a chronic Hepatitis B, if he still has positive HBsAg. This would be justified if he had converted to negative HBsAg and if it can not be detected quantitatively. Unless better opinion ...
Indeed whether a person has Hepatitis B is determined, at the present time, by testing the status of HBsAg. However, not all chronic Hepatitis B patients require treatment, some can wait and be monitored. To determine whether treatment is needed, the viral load, a quantitive measure of hbvdna in the blood, using pcr method, is required together with ALT and HBeAg status at the very least.
Since PCR detects quantitative viremia, the main aim is for prognosis monitoring and to monitor treatment effectiveness as if there is good therapeutic response or not and if there is a need to change therapy or not..
No clear answer to your question, however most studies and guidelines considers ELISA as screening test/technique. Furthermore, PCR has found to be more reliable than ELISA as comparative studies have reported that some negative sera with ELISA became positive with PCR.....I think to my knowledge, these variations are contributed by weakness and strength between the two techniques in detection of HBV variants.
References;
Article DETECTION OF HEPATITIS B SURFACE ANTIGEN USING ELISA AND REAL TIME PCR
https://www.who.int/diagnostics_laboratory/evaluations/en/hep_B_rep1.pdf
Dear Vitus,
i appreciate ur ans, so for answered, ur is most relevant regarding my question but still if we think ye Elisa is almost screening but still it detects HBsAg as pcr can also detects HBs in the blood if viremia is there, then why extra burden has to be beard by the patients as PCR is too costly. in case of negative Sera and false positive elisa pcr is best but its probability is too low.
hava a surface antigene (HBsAg) does not mean you already had a fully complete gene of HBV, we know that the surface encoding gene is a small encoding gene from the entire gene of HBV even it overlap, so integration of suface gene on your liver cell can't produce Pregenomic DNA for produce overal part of HBV or i can say even you already had a surface gene you can't even say that you already had a viral DNA or infected. for physician it's really important to minimize human error or re-check the real condition of the patients, ya i guess two methods can be more acurate than using 1 method. why ? if there any case that sera negative on ELISA but positive by PCR amplification on surface, then it will be continue to other step for amplification another part or HBV DNA, maybe polymerase encoding gene or other target to ensure is patients really infected. or maybe negative on PCR but positive on ELISA, it should be any other reason in this case, but literally i think it for confirmation because you want to treat a human in this case. otherhand i can't put you on group of infected HBV just because you already had a surface, i'll put you if you already had a polymerase gene or complete gene of HBV after see your PCR ampification report Sajid Ali
ELISA is the initial diagnosis in resource poor settings. Quantification is important for monitoring and prognostic evaluation and automated systems are highly sensitive and efficient for this purpose.
HBV is a funny little critter, it is quite possible for a patient to produce (over decades) viral protein (antigen), but no nucleic acid and no complete virions. What this would mean for the patient's risk for complications like liver cancer I don't know. At least, it makes sense to assay all aspects of viral replication.