Clinical Evaluation of a Low Cost, In-House Developed Real-Time RT-PCR Human Immunodeficiency Virus Type 1 (HIV-1) Quantitation Assay for HIV-1 Infected Patients

<div><p>Objectives</p><p>HIV-1 viral quantitation is essential for treatment monitoring. An in-house assay would decrease financial barriers to access.</p><p>Materials and Methods</p><p>A real-time competitive RT-PCR in house assay (Sing-IH) was developed in Singapore. Using HXB2 as reference, the assay's primers and probes were designed to generate a 183-bp product that overlaps a portion of the LTR region and <i>gag</i> region. A competitive internal control (IC) was included in each assay to monitor false negative results due to inhibition or human error. Clinical evaluation was performed on 249 HIV-1 positive patient samples in comparison with the commercially available Generic HIV Viral Load assay. Correlation and agreement of results were assessed for plasma HIV-1 quantification with both assays.</p><p>Results</p><p>The assay has a lower limit of detection equivalent to 126 copies/mL of HIV-1 RNA and a linear range of detection from 100–1000000 copies/mL. Comparative analysis with reference to the Generic assay demonstrated good agreement between both assays with a mean difference of 0.22 log₁₀ copies/mL and 98.8% of values within 1 log₁₀ copies/mL range. Furthermore, the Sing-IH assay can quantify HIV-1 group M subtypes A–H and group N isolates adequately, making it highly suitable for our region, where subtype B and CRF01_AE predominate.</p><p>Conclusions</p><p>With a significantly lower running cost compared to commercially available assays, the broadly sensitive Sing-IH assay could help to overcome the cost barriers and serve as a useful addition to the currently limited HIV viral load assay options for resource-limited settings.</p>