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Updated: Mar 25, 2026
Amplifying and Quantifying HIV-1 RNA in HIV Infected Individuals with Viral Loads Below the Limit of Detection by Standard Clinical Assays
Published on: September 26, 2011
Aptima HIV-1 Quant Dx--A fully automated assay for both diagnosis and quantification of HIV-1
Sangeetha Vijaysri Nair1, Hee Cheol Kim1, Jacqueline Fortunko1
1Hologic Incorporated, San Diego, CA, USA.
Background:
Separate assays are available for diagnosis and viral load (VL) monitoring of HIV-1. Studies have shown that using a single test for both confirmatory diagnosis and VL increases linkage to care.
Objective:
To validate a single assay for both diagnosis and VL monitoring of HIV-1 on the fully automated Panther platform.
Study Design:
Validate the assay by assessing specificity, sensitivity, subtype detection, seroconversion, reproducibility and linearity. Also assess diagnostic agreement with the Procleix(®) Ultrio Elite™ discriminatory assay (Procleix), and agreement of VL results (method comparison) with Ampliprep/COBAS TaqMan HIV-1 version 2.0 (CAP/CTM), using clinical samples.
Results:
The assay was specific (100%) and sensitive with a 95% limit of detection of 12 copies/mL with the 3rd WHO standards. Aptima detected HIV in seroconversion panels 6 and 11 days before p24 antigen and antibody tests, respectively. Diagnostic agreement with Procleix, was 100%. Regression analysis showed good agreement of VL results between Aptima and CAP/CTM with a slope of 1.02, intercept of 0.07, and correlation coefficient (R(2)) of 0.97. Aptima was more sensitive than CAP/CTM. Equivalent quantification was seen on testing clinical samples and isolates belonging to HIV group M, N, O and P and commercially available subtype panels. Assay results were linear (R(2) 0.9994) with standard deviation of <0.17 log copies across assay range.
Conclusions:
The good specificity, sensitivity, precision, subtype performance and clinical agreement with other assays demonstrated by Aptima combined with the complete automation provided by the Panther platform makes Aptima a good candidate for both VL monitoring and diagnosis of HIV-1.
