HBV Genotypic Drug Resistance Testing

Scope of the tests

Decreased susceptibility of HBV to antiretroviral drugs (phenotypic drug resistance) is usually associated with sequences changes in the viral genome (genotypic drug resistance). Detection of these mutations in the viral genome can be used to accurately predict the susceptibility of the virus to currently licensed antiviral drugs used to treat HBV infection and thus can be used to optimise the use of antiviral treatment on an individual patient basis. Currently, the Molecular Diagnostics Unit (MDU) routinely offers sequencing of the polymerase gene of HIV-1 of plasma viral DNA. Samples with any viral load greater than 50 HBV DNA copies/ml plasma can be analysed, although increased assay failure rates are seen with low-load samples.

Test details

The test generates a sequence covering the whole of the HBV polymerase gene (344 codons). The method is a fully validated in-house method. A summary of the validation is available from the Unit Manager.

Results reporting

The raw data produced by the resistance assay is an edited nucleotide sequence. To generate a usable report this sequence is submitted to an on-line algorithm hosted by the Max Planck Institute (http://www.geno2pheno.org). The geno2pheno interpretation is pasted into the final MDU report. If the user requires the sequence file (“FASTA” file) or the raw data chromatograms these can be supplied by arrangement with the Unit Manager.

Turnaround time

We aim to issue reports within two weeks of receiving a sample. However, as we offer a bespoke service and make rigorous efforts to produce a result from any sample, turnaround times may be extended if repeat testing is required.

Charges

The current charges for HBV resistance testing is £100.

Complaints

If you are unhappy with the service provided by MDU or if you wish to make suggestions on how our service can be improved, please contact the Unit Manager.