Detection of Diverse HIV Strains by the m-PIMA^TM HIV-1/2 Detect Point-of-Care Assay

Human Immunodeficiency Virus (HIV) is a highly diverse and mutable virus, presenting significant challenges for diagnostic assays. HIV-1, the predominant type, is categorized into four groups (M, N, O, and P), with Group M further divided into nine subtypes (A-D, F-H, J, K) and numerous circulating recombinant forms (CRFs) and unique recombinant forms (URFs). HIV-2 also exhibits substantial diversity across its subtypes (A-H) and CRFs. This genetic complexity poses a significant challenge for diagnostic assays, which often rely on detecting conserved sequences within the viral genome. Traditional diagnostic methods may fail to detect rare or divergent strains, leading to false negatives and missed diagnoses.

Fig.1 Performance of m-PIMA HIV-1/2 Detect on a challenge panel consisting of HIV-1/2 groups, subtypes, CRFs, and URFs (n = 340). (Anderson M., et al., 2025)

The m-PIMA HIV-1/2 Detect Assay: A Comprehensive Solution

The m-PIMA HIV-1/2 Detect assay, developed by Abbott Diagnostics, represents a significant advancement in HIV diagnostics. This qualitative point-of-care (POC) multiplex RT-PCR assay is designed to detect HIV-1 and HIV-2 RNA in whole blood and plasma samples. The assay targets multiple regions of the viral genome, including the 5' LTR, gag, and pol regions of HIV-1, and the 5' LTR region of HIV-2. By using eight primers and probes for HIV-1 and five for HIV-2, the m-PIMA HIV-1/2 Detect assay can detect a wide range of viral strains with high sensitivity and specificity.

Study Design and Methodology

To evaluate the effectiveness of the m-PIMA HIV-1/2 Detect assay, a comprehensive study was conducted using a diverse panel of 340 serum/plasma specimens and diluted cultured virus isolates. This panel included representatives of HIV-1 groups M, N, O, P, various subtypes, CRFs, URFs, and HIV-2. The study also included an in silico analysis of 53,503 HIV-1 and 68 HIV-2 sequences from the National Center for Biotechnology Information (NCBI) database to predict the assay's performance against a broader range of circulating strains.

High Detection Rates Across Diverse Strains

The results of the study demonstrated the m-PIMA HIV-1/2 Detect assay's exceptional ability to detect a wide range of HIV strains. The assay detected HIV in 329 out of 340 tested samples (96.8%). Among samples with a viral load (VL) greater than 4000 copies/mL (the assay's design sensitivity), detection was 100%. Even at lower viral loads (between 3.0 and 3.6 log copies/mL), the assay detected 96.9% of samples. For samples with a VL below 3.0 log copies/mL, the detection rate was 87.3%. Importantly, the assay detected at least one member from each subtype/CRF and all URFs tested.

In Silico Analysis: Predicting Broader Performance

The in silico analysis further supported the assay's inclusivity. Out of 53,503 HIV-1 sequences analyzed, only 2 (0.0037%) had mutations that could potentially reduce detection below the 90% identity threshold. For HIV-2, only 1 out of 68 sequences (1.47%) had such mutations. This suggests that the m-PIMA HIV-1/2 Detect assay is highly effective in detecting the vast majority of circulating HIV strains.

Implications for HIV Diagnosis and Treatment

The ability to detect a wide range of HIV strains is crucial for achieving the UNAIDS 95-95-95 goals, which aim to ensure that 95% of people with HIV know their status, 95% of those diagnosed receive antiretroviral therapy, and 95% of those on therapy achieve viral suppression. The m-PIMA HIV-1/2 Detect assay's high sensitivity and inclusivity make it a valuable tool for rapid, accurate diagnosis, especially in resource-limited settings where access to advanced diagnostic technologies may be limited.

Clinical Impact and Future Directions

The m-PIMA HIV-1/2 Detect assay not only addresses the challenge of HIV diversity but also offers significant advantages in terms of speed and accessibility. Its rapid turnaround time (results available within 70 minutes) and the ability to use small sample volumes (25 µL of whole blood or plasma) make it particularly suitable for point-of-care settings. This assay can be used for early infant diagnosis (EID), where timely detection is critical for initiating antiretroviral therapy and improving outcomes.

Moreover, the m-PIMA HIV-1/2 Detect assay's robust performance across diverse strains suggests that it can be a reliable tool for global HIV surveillance. By accurately detecting both common and rare variants, this assay can help monitor the spread of HIV and inform public health strategies. Future research should focus on expanding the sample size to include more rare subtypes and groups, as well as comparing the performance of the m-PIMA HIV-1/2 Detect assay with other diagnostic platforms.

Conclusion: A New Era in HIV Detection

The m-PIMA HIV-1/2 Detect assay represents a significant breakthrough in HIV diagnostics. Its ability to detect a wide range of HIV strains, including rare and divergent forms, makes it a powerful tool in the fight against HIV. With its rapid turnaround time and high sensitivity, this POC assay can help ensure that more people know their HIV status and receive the care they need. As researchers continue to monitor and address the evolving diversity of HIV, assays like the m-PIMA HIV-1/2 Detect will play a critical role in improving global health outcomes.

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Reference

Anderson, Mark, et al. "Detection of Diverse HIV Strains by the m-PIMATM HIV-1/2 Detect Point-of-Care Assay." Journal of Clinical Virology (2025): 105771.

This article is for research use only. Do not use in any diagnostic or therapeutic application.

Detection of Diverse HIV Strains by the m-PIMATM HIV-1/2 Detect Point-of-Care Assay