Interlaboratory concordance of DNA sequence analysis to detect reverse transcriptase mutations in HIV-1 proviral DNA

Thirteen laboratories evaluated the reproducibility of sequencing methods to detect drug resistance mutations in HIV-1 reverse transcriptase (RT). Blinded, cultured peripheral blood mononuclear cell pellets were distributed to each laboratory. Each laboratory used its preferred method for sequencing proviral DNA. Differences in protocols included: DNA purification: number of PCR amplifications; PCR product purification; sequence/location of PCR/sequencing primers; sequencing template; sequencing reaction label; sequencing polymerase; and use of manual versus automated methods to resolve sequencing reaction products. Five unknowns were evaluated. Thirteen laboratories submitted 39 043 nucleotide assignments spanning codons 10-256 of HIV-I RT. A consensus nucleotide assignment (defined as agreement among greater than or equal to 75% of laboratories) could be made in over 99% of nucleotide positions, and was more frequent in the three laboratory isolates. The overall rate of discrepant nucleotide assignments was 0.29%. A consensus nucleotide assignment could not be made at RT codon 41 in the clinical isolate tested. Clonal analysis revealed that this was due to the presence of a mixture of wild-type and mutant genotypes. These observations suggest that sequencing methodologies currently in use in ACTG laboratories to sequence HIV-I RT yield highly concordant results for laboratory strains; however, more discrepancies among laboratories may occur when clinical isolates are tested. (C) 1998 Elsevier Science B.V.