Performance characteristics of an antibody-based multiplex kit for determining recent HIV-1 infection.

The availability of reliable laboratory methods for determining recent HIV infection is vital for accurate estimation of population-based incidence. The mean duration of recent infection (MDRI) and false recent rate (FRR) are critical parameters for HIV incidence assays, as they impact HIV incidence estimates and provide a measure of assay performance. The HIV-1 Multiplex assay is an in-house developed, magnetic bead-based assay that measures virus-specific antibody levels and avidity to multiple analytes. To ensure quality control and to facilitate transfer of the assay to external laboratories or testing facilities, the in-house assay has been adapted and produced in kit form. Here, we describe the performance characteristics of the multiplex kit and demonstrate the stability of the kit components over a one-year period. Two statistical methods were employed to estimate the MDRI of the individual analytes and five different algorithms, combining multiple analyte values. The MDRI estimates for the individual analytes and five algorithms were all between 200 and 300 days post-seroconversion, with no notable difference between the two statistical approaches. All five algorithms exhibited a 0% FRR with specimens from long-term, subtype B HIV-1-infected individuals. The assay parameters described in this study provide the necessary tools to implement the HIV-1 multiplex assay and improves the utility of the assay for field use

HIV-1 Multiplex assay kit stability.

<p>Levey-Jennings plots of high (closed circles) and low (open circles) positive controls over a 12 month period. The straight solid line represents the mean assay value of the high positive control, while the dashed lines represent 2 standard deviations above and below the mean.</p

Longitudinal antibody responses to individual analytes.

<p>The MFI-n and AI values for 95 recent seroconverters (n = 608) were plotted over days since estimated seroconversion. The solid red lines represent prediction curves from fitting random intercept models implementing a 3-parameter function, avidity = , for avidity measures and a 2-parameter function, OD = (<i>days</i> * <i>A</i>)/(<i>days</i> + <i>B</i>), for MFI-n values.</p

Intra-assay algorithms.

<p>The combined algorithm value for the mean normalized MFI, mean avidity index, principle component, and standardized score methods were plotted over days since estimated seroconversion. The solid red lines represent prediction curves from fitting random intercept models implementing a four-parameter function, score = . Note, the multi-analyte algorithm is not included in the figure since the algorithm takes into account each individual analyte cutoff and does not generate a combined value or score.</p

Performance characteristics of Multiplex HIV-1 incidence kit.

<p>Performance characteristics of Multiplex HIV-1 incidence kit.</p