Rapidly adaptable automated interpretation of point-of-care COVID-19 diagnostics

A portable, integrated microfluidics for rapid and sensitive diagnosis of Streptococcus agalactiae in resource-limited environments

Streptococcus agalactiae (Group B Streptococcus, GBS) has been the leading cause of infections in newborns. Rapid and accurate diagnosis of GBS in pregnant women is a deterministic strategy to prevent newborn infection. Conventional detection methods based on nucleic acid amplification assay have been applied in GBS diagnosis in central laboratories, with demonstrated high sensitivity. However, their heavy dependence on instrumentation and trained technicians forms remarkable obstacles to GBS detection in wide scenarios, including self-testing, and bedside-/community-screening. Furthermore, the structures of GBS bring about extra challenges to the nucleic acid extraction and purification. Novel GBS diagnosis platforms integrating sample processing, amplification, and read-out, are highly desired in clinical. Here, we report a portable, integrated microfluidics that enables rapid extraction of DNA from sampling swabs (<10 min), power-free DNA amplification (<30 min), and simple read-out in GBS detection. The platform works without an external pump, achieving rapid and highly efficient DNA extraction from clinical samples, with a significantly reduced time from 6 h to less than 50 min. Systematic clinical tests based on 47 patient samples validated the high performance of the platform, highlighted with a low limit of detection (LOD, 103 copies/ml), high sensitivity (100%), and specificity (100%). Head-to-head comparisons showed that the device improved the LOD by an order of magnitude than the traditional PCR method, showing a simple yet powerful POCT platform for home-/community-based testing towards GBS (and other pathogens) prevention in remote areas.

Measuring the performance of computer vision artificial intelligence to interpret images of HIV self-testing results

Introduction

HIV self-testing (HIVST) is highly sensitive and specific, addresses known barriers to HIV testing (such as stigma), and is recommended by the World Health Organization as a testing option for the delivery of HIV pre-exposure prophylaxis (PrEP). Nevertheless, HIVST remains underutilized as a diagnostic tool in community-based, differentiated HIV service delivery models, possibly due to concerns about result misinterpretation, which could lead to inadvertent onward transmission of HIV, delays in antiretroviral therapy (ART) initiation, and incorrect initiation on PrEP. Ensuring that HIVST results are accurately interpreted for correct clinical decisions will be critical to maximizing HIVST's potential. Early evidence from a few small pilot studies suggests that artificial intelligence (AI) computer vision and machine learning could potentially assist with this task. As part of a broader study that task-shifted HIV testing to a new setting and cadre of healthcare provider (pharmaceutical technologists at private pharmacies) in Kenya, we sought to understand how well AI technology performed at interpreting HIVST results.

Methods

At 20 private pharmacies in Kisumu, Kenya, we offered free blood-based HIVST to clients ≥18 years purchasing products indicative of sexual activity (e.g., condoms). Trained pharmacy providers assisted clients with HIVST (as needed), photographed the completed HIVST, and uploaded the photo to a web-based platform. In real time, each self-test was interpreted independently by the (1) client and (2) pharmacy provider, with the HIVST images subsequently interpreted by (3) an AI algorithm (trained on lab-captured images of HIVST results) and (4) an expert panel of three HIVST readers. Using the expert panel's determination as the ground truth, we calculated the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for HIVST result interpretation for the AI algorithm as well as for pharmacy clients and providers, for comparison.

Results

From March to June 2022, we screened 1,691 pharmacy clients and enrolled 1,500 in the study. All clients completed HIVST. Among 854 clients whose HIVST images were of sufficient quality to be interpretable by the AI algorithm, 63% (540/854) were female, median age was 26 years (interquartile range: 22-31), and 39% (335/855) reported casual sexual partners. The expert panel identified 94.9% (808/854) of HIVST images as HIV-negative, 5.1% (44/854) as HIV-positive, and 0.2% (2/854) as indeterminant. The AI algorithm demonstrated perfect sensitivity (100%), perfect NPV (100%), and 98.8% specificity, and 81.5% PPV (81.5%) due to seven false-positive results. By comparison, pharmacy clients and providers demonstrated lower sensitivity (93.2% and 97.7% respectively) and NPV (99.6% and 99.9% respectively) but perfect specificity (100%) and perfect PPV (100%).

Conclusions

AI computer vision technology shows promise as a tool for providing additional quality assurance of HIV testing, particularly for catching Type II error (false-negative test interpretations) committed by human end-users. We discuss possible use cases for this technology to support differentiated HIV service delivery and identify areas for future research that is needed to assess the potential impacts-both positive and negative-of deploying this technology in real-world HIV service delivery settings.