HIV-1 genotypic drug resistance testing on dried blood spots

Objective To assess the feasibility of HIV-1 resistance genotyping using dried blood spot specimens.Methods Peripheral vein anticoagulant blood was collected freshly from the studied subjects and deposited on filter paper.After viral RNA extraction,nested RT-PCR was used to amplify HIV pol gene.The amplified sequences were analyzed using the Bioedit software,and the data regarding drug resistance mutations and subtype were obtained using the Stanford software.Viral load(VL)was tested by Bayer R 340 bDNA assay in plasma samples.Results Sixteen samples with VL1 000copies/ml were all amplified positive by RT-nested PCR with both DBS and plasma.Of the 8 samples with VL1 000copies/ml,2 were amplified positive in plasma sample and 0 in DBS sample.There were parallel results between the DBS and plasma samples including subtype analysis and resistance related mutation.The results of subtyping showed that all samples(11)were subtyped as HIV-1 AE.A high level of resistance to nucleoside reverse transcriptase inhibitors(NRTIs)(6/7)and non-nucleoside reverse transcriptase inhibitors(NNRTIs)(5/7)was observed in 7 patients with treatment.They developed to a different extent multiple drug resistance.Conclusion It is feasible to use this dried blood spot method for monitoring resistance to antiretroviral drugs and subtype analysis.The simplicity of sample preparation,long length storage and convenient transport makes DBS a cost effective and suitable alternative tool for collecting blood sample in resource limited areas and patients who are difficult for collecting blood samples.