Evaluation of the performance of a novel HIV-1 viral load assay for HIV quantification in China
Xizi Deng1, Liya Li1, Xiaoli Cai1
1Guangzhou Eighth People's Hospital, Guangzhou Medical University, Guangzhou, China.
Objectives:
Our objective was to assess the HIV-1 quantification performance of the Livzon HIV-1 viral load (VL) assay and the Roche Cobas HIV-1 assay to evaluate an HIV-1 VL testing reagent for application in China.
Method:
We compared the Livzon and Roche Cobas HIV-1 VL assays using ethylenediaminetetraacetic acid plasma samples collected between May 2021 and November 2021 from patients with HIV-1 and healthy controls. We used Cohen's κ coefficient to measure agreement of qualitative values and Pearson's correlation coefficient (r) values and the coefficient of determination (R2 ) to determine the linear relationship between the two assays. We performed a Bland-Altman analysis to assess VL quantification agreement.
Results:
In total, 11 plasma samples from patients with hepatitis B virus (HBV) or hepatitis C virus (HCV) and nine samples from healthy controls were undetectable on both assays. Overall agreement was seen in 419 of 500 specimens (91.40%), with a κ value of 0.59. Pearson's correlation coefficient between the two assays was 0.970. Using the Bland-Altman method, 95.14% (352/370) of paired VLs fell within the 95% confidence limits of agreement (-0.51 to 0.95 log10 copies/mL). Higher VLs had a better correlation and a smaller mean difference between the two assays. Pearson's correlation coefficient for the samples of subtype CRF01_AE, CRF07_BC, and CRF55_01B was 0.950, 0.935, and 0.952, respectively.
Conclusion:
The Livzon HIV-1 VL assay exhibits good precision and linearity and a high correlation with the Roche Cobas HIV-1 assay. The Livzon HIV-1 VL assay has salient advantages in terms of the lyophilized powder reagent, which gives the assay greater stability and sensitivity and can be readily used in low-resource areas.
