Clinical evaluation of Xpert HIV Qual XC assay in diverse HIV-1 subtypes circulating in China.

BACKGROUND

Early and accurate HIV-1 diagnosis is crucial for timely treatment initiation and transmission prevention. This study evaluated the clinical performance of the Xpert HIV Qual XC assay in detecting HIV-1 across diverse subtypes in China.

METHODS

A total of 242 whole blood samples (215 HIV-1-positive, 15 negative, plus 12 with non-HIV pathogens) were tested. Sensitivity, specificity, kappa coefficient, and correlations between Ct values and log₁₀ viral loads were analyzed. Operational performance was compared to the COBAS AmpliPrep/COBAS TaqMan HIV-1 Qualitative Test v2.0 (referred to as the COBAS system) regarding turnaround time (TAT) and reagent usage efficiency.

RESULTS

The Xpert assay demonstrated a high sensitivity of 99.07 % and a specificity of 100.00 %, with an overall agreement of 99.18 % with clinical diagnoses. The detection rates varied by viral load and achieved 100.00 % accuracy for samples with viral loads above 50 copies/mL, but decreased to 84.62 %(11/13) for samples with extremely low viral loads (<50 copies/mL). The assay successfully detected a wide range of HIV-1 subtypes, including CRF07_BC, CRF01_AE, and CRF08_BC, which reflects the genetic diversity in China. Additionally, the Xpert assay provides rapid results within 90 min and requires fewer reagents than COBAS system, making it a viable point-of-care testing option.

CONCLUSIONS

The Xpert HIV Qual XC assay shows excellent performance across diverse HIV-1 subtypes and is well-suited for decentralized diagnostic settings, supporting improved early diagnosis of HIV and treatment efforts.