Evaluation of the Abbott HBV RUO sequencing assay combined with laboratory-modified interpretive software

The Abbott HBV RUO Sequencing assay (Abbott Molecular Inc., Des Plaines, IL), which combines automated sample processing, real-time PCR, and bidirectional DNA sequencing, was evaluated for detection of nucleos(t)ide analogue (NA) resistance-associated mutations located in the hepatitis B virus (HBV) polymerase (Pol) gene. Interpretive software from the assay manufacturer was modified to allow interrogation of the overlapping HBV surface (S) gene sequence for HBV genotype determination and detection of immune escape mutations. Analytical sensitivity (detection and sequencing) of the assay was determined to be 103.9 IU/ml (95% confidence interval [CI], 80.0 to 173.3) for HBV genotype A. Testing of commercially available HBV genotype panels consisting of 23 individual members yielded complete agreement between expected results and results obtained from the laboratory-developed HBV genotype library. Excellent specificity was observed among clinical specimens with serologic or molecular markers for various unrelated blood-borne viruses (n = 6) and sera obtained from healthy, HBV-negative blood donors (n = 20). Retrospectively selected clinical specimens tested by a commercial reference laboratory HBV sequencing assay (n = 54) or the Trugene HBV Genotyping kit (n = 7) and the Abbott HBV RUO Sequencing assay showed minor differences in detection and reporting of NA resistance-associated mutations in 7 of 61 (11.5%) specimens but complete agreement of genotype results. The Abbott HBV RUO Sequencing assay provided a convenient and efficient assay workflow suitable for routine clinical laboratory use, with the flexibility to be modified for customized detection of NA resistance-associated mutations, HBV genotype determination, and detection of immune escape mutations from a single contiguous HBV sequence.