The limit of detection (LoD) is defined as the concentration of HIV-1 RNA that is detected at 95% or greater probability according to CLSI EP17-A2 (37). The Aptima HIV-1 Quant assay’s LoD in subtype B samples (3rd International WHO Standard) is 12 copies/mL.
Limit of Detection Using the 3rd Party HIV-1 WHO International Standard
Limit of Detection Across HIV-1 Subtypes and Groups
Lower Limit of Quantitation
The Aptima HIV-1 Quant assay’s lower limit of quantitation (LLoQ) was established and verified using the strict CLSI guidelines. The LLoQ of the assay is set at the highest concentration of all subtypes tested: 30 copies/mL.
Verification of the LLoQ by HIV-1 Subtype or Group
Linearity of the Aptima HIV-1 Quant Assay
Linearity Across the Dynamic Range
Linearity Across Groups and Subtypes
The Aptima HIV-1 Quant assay offers precise quantitation across the linear range in addition to accurate quantitation.
Precision is maintained in samples with low-viremia with narrow CV of less than 10% in samples with 1.80 log copies/mL HIV-1.
Precision of the Aptima Quant Assay
CV=coefficient of variation, SD=standard deviation
a This panel member was diluted 1:3 with specimen diluent and tested to evaluate the precision of the diluted sample.
Note: Variability from some factors may be numerically negative, which can occur if the variability due to those factors is very small. When this occurs, SD=0 and CV=0%. The total number of replicates tested was 162 for each panel; only replicates with a numerical value were analyzed.
Correlation Between Aptima HIV-1 Quant Assay and Comparator Assay