Point-of-Care Tests for HIV and T pallidum Infections: Utility of Smartphone-Based Electronic Reader

A smartphone-based electronic reader was found to be accurate and reliable in rapid dual point-of-care (POC) tests for antibodies to human immunodeficiency virus (HIV) and Treponema pallidum infections, according to a study published recently in Sexually Transmitted Diseases.¹

The study evaluated the sensitivity and specificity of the Cellmic HRDR-200 smartphone-based electronic reader using 201 serum specimens tested with 2 dual rapid tests for antibodies to HIV and T pallidum. Testing was performed at 2 study sites: Los Angeles, California, and Lima, Peru. All tests were also read visually. The presence of HIV and T pallidum antibodies in studied sera was confirmed using enzyme immunoassay coupled with Western blot, and T pallidum particle agglutination test, respectively.

 “There were no significant differences between the accuracies of visual and electronic readings, although the sensitivity of visual readings was higher than their electronic counterparts,” the investigators wrote in their paper. The specificities for detection of T pallidum using the electronic reader were 99.1% and 99.0% in the 2 rapids tests; the specificity for detection of HIV using the electronic reader was 100% in both tests. The sensitivities for detection of T pallidum and HIV using the electronic reader ranged from 86.5% to 97.0% in the 2 rapid tests.

These findings shed new light on the applicability of smartphone-based electronic readers in POC testing and complement the growing interest in this technology. Smartphones have several advantages over other imaging technologies: small size and weight, ease-of-use, and economical price. Smartphone-based electronic readers are considered a promising technology whose application in POC testing could lead to significant improvements, especially in decentralization of POC testing and real-time collection of data.¹

 “By recording and transmitting data as they are collected, electronic readers can help monitor quality assurance, supply chain management, and real-time disease surveillance,’” the investigators wrote in their article. The results of their latest study are in line with these expectations and “show the Cellmic reader to be a promising option for increasing the use of point-of-care testing programs.”

Study limitations

• Serum samples used in the study were stored and previously characterized —  the thawing and refreezing process might have affected the study results; ideally, the study should have been performed in a field setting using finger prick whole blood
• Small sample size – only 2 populations (study sites) were included in the study
• The study was narrowly focused on measuring accuracy, while other parameters, such as performance, use, and optimal features of electronic readers were not studied

Reference

Herbst de Cortina S, Bristow CC, Humphries R, et al. Laboratory evaluation of a smartphone-based electronic reader of rapid dual point-of-care tests for antibodies to human immunodeficiency virus and Treponema pallidum infections. Sex Transm Dis. 2017;44(7):412-416. doi:10.1097/OLQ.0000000000000628