# Performance evaluation of a novel RapiSafe HIV Ag/Ab combi rapid test for the detection of HIV antigen and antibodies

## TL;DR

This paper evaluates a new HIV rapid test called RapiSafe, which detects HIV antigens and antibodies with high sensitivity and specificity, especially in early infection stages.

## Contribution

The study introduces RapiSafe, a novel rapid test with improved antigen detection and sensitivity for acute HIV infection compared to existing tests.

## Key findings

- RapiSafe showed lower antigen detection limits for HIV-1 subtypes A1, C, and D compared to the Abbott Determine test.
- It detected more seroconversion reactive cases and antigen-positive acute HIV serum samples than existing methods.
- The test maintained high specificity (99.75-100%) across different specimen types and potential cross-reacting substances.

## Abstract

The detection of acute HIV infection (AHI) is vital for timely diagnosis and appropriate management, thus, in vitro diagnostic tests that accurately identify antigen and anti-bodies separately, have a short seroconversion window period, rapid turnaround time are essential. This study aimed to evaluate the analytical and clinical performance of the RapiSafe rapid test, with a particular focus on its efficacy in detecting AHI in serum samples.

Antigen sensitivity was evaluated in 1st WHO International Standard for HIV-1 p24 Antigen (NIBSC 22/230) and Reference Panel (NIBSC 16/210). Five HIV-1 seroconversion panels and one HIV-1 p24 antigen Mixed Titer Performance Panel were detected for HIV-1 p24 antigen seroconversion sensitivity evaluation. 22 treatment-naïve acute HIV-1 serum at Fiebig stage III-VI were detected with both the RapiSafe and the Determine tests. To evaluate the diagnostic sensitivity in different genotypes and specimen types of HIV-1 established infections, HIV positive serum and venous whole blood were detected. Diagnostic specificity was evaluated in clinical serum, plasma, capillary whole blood, and venous whole blood.

Compared with the Abbott Determine tests, the RapiSafe showed lower antigen detection limits in HIV-1 subtypes A1, C, and D; higher p24 antigen sensitivity with five more seroconversion reactive detections; and one more antigen-positive AHI serum detection. The superior antigen and antibodies sensitivity of the RapiSafe among serum, plasma, and venous whole blood did not compromise specificity (99.75-100%) among different specimen types with potentially cross-reacting substances or unrelated medical conditions.

The exceptional performance of the RapiSafe in antigen and antibodies detection among different subtypes and specimen types makes it a valuable tool in HIV diagnosis. Its novel approach could significantly impact global HIV control by facilitating early detection and timely intervention, which are essential for the uptake of prevention, prompt HIV diagnosis, and mitigating global HIV transmission risks.