2025 · Journal of clinical microbiology · open access
Clinical development and performance of the First to Know Syphilis Self-Test for over-the-counter usage: a <i>de novo</i> rapid test for treponemal antibody
Clark et al.
The finding, in our words
The First to Know Syphilis Self-Test, using self-collected fingerstick capillary blood, demonstrated 93.4% sensitivity and 99.5% specificity against a composite reference standard in a 1,270-subject study. This over-the-counter test enables patient-centric screening at home, which could improve early detection and reduce transmission of syphilis and associated STIs.
A paraphrase to the Library’s standard, never the abstract. The source is one link away and is always the authority.
The Tasso+ device, which uses a vacuum to collect capillary blood from the upper arm, gathered an average of 536 microlitres of whole blood from 47 men who have sex with men using PrEP, with 91% of samples sufficient for HIV testing and 89% for syphilis testing. Acceptability was high, with 87% expressing a positive attitude and 77% willing to use the device again for home self-sampling.
Capillary blood samples collected by staff or self-collected by participants showed strong correlation and clinically acceptable agreement with venipuncture for influenza haemagglutination inhibition titers. The small differences observed were not clinically meaningful, and adequate sample volume was achieved in most attempts, supporting the feasibility of decentralised serological testing.
In a cohort of 62 participants evaluating home self-collection with the TassoPlus device, 38 returned samples, with 29% excluded due to insufficient plasma volume below 200 ΔL. Although viral load measurements in adequate samples correlated well with conventional testing (r = 0.800), the high failure rate and missed detection in low-volume viremic samples indicate that further technical refinements are necessary before clinical adoption.
A study of decentralised patient-centric microsampling found that 82% of untrained participants, 47 of 57, successfully self-collected acceptable fingerstick blood in Microtainer tubes. All 46 tested samples yielded accurate HIV viral suppression results compared to venipuncture, though this remote monitoring approach is limited to US courier services and temperature conditions.
In 30 adult solid organ transplant recipients, capillary blood self-collected using the Tasso+ device showed 91% concordance with venous samples for detecting CMV DNAemia above the limit of detection, with excellent quantitative correlation (Spearman R² = 0.99). Most participants preferred self-collection over venipuncture, suggesting the device could enable decentralised viral monitoring, though sensitivity was lower (95% at 308 IU/mL).