Canadian Public Health Laboratory Network guidelines for the use of point-of-care tests for Treponema pallidum in Canada

Abstract

Over the past few years, the increase in infectious syphilis outbreaks in major urban centres and remote or rural locations in Canada, often affecting hard-to-reach patient populations, has renewed an interest and urgency in studying the use of point-of-care tests (POCTs) that can provide test results at the time and place of primary health care delivery, obviating the repeat visit necessary with traditional syphilis serology or molecular diagnostic tests. In 2015, the Canadian Public Health Laboratory Network released its first laboratory guideline for the use of POCTs in the diagnosis of syphilis in Canada. Although Canada has no licensed POCT, two POCTs (Syphilis Health Check and the DPP¯ HIV Syphilis System) have received US Food and Drug Administration (FDA) approval under premarket approval applications. Most syphilis POCTs detect antibodies to treponemal antigens, so their results cannot be used to differentiate between active and past infection. The only POCT that detects antibodies to both treponemal and non-treponemal antigens does not yet have Health Canada or FDA approval. In this updated guideline, the current landscape of POCTs for syphilis, with an emphasis on data from low-prevalence countries, is described. Individual operators should consider the questions of where, when, how, and why a POCT is used before its actual implementation. Training in the operation and interpretation, quality control, proficiency program, safety, and careful documentation of the process and results are especially important for the successful implementation of POCTs.

Rapid Syphilis Testing

“…The presence of treponemal antigens can indicate a current or past infection, so tests for treponemal antigens alone cannot confirm a current infection. 1 A positive treponemal test is usually confirmed with a non-treponemal test.…”

“…11 These tests require time to complete and a patient will be tested, diagnosed, and treated across a number of appointments. 1 Although there may be circumstances in which the benefit of treponemal tests alone for diagnosis (instead of screening) may outweigh the risk of overtreatment, WHO recommends that all positive point-of-care tests for syphilis be confirmed using a standard laboratory test. 1…”

Treponemal point-of-care tests for syphilis

“…1,2 Conventional screening for syphilis involves serologic laboratory testing. [1][2][3][4] Barriers to accessing screening and delays to treatment created by lengthy test turnaround times may be addressed by POCTs. 3,4 Pointofcare tests may be particularly beneficial in prenatal care settings and in communities with emerging syphilis outbreaks.…”

“…[1][2][3][4] Barriers to accessing screening and delays to treatment created by lengthy test turnaround times may be addressed by POCTs. 3,4 Pointofcare tests may be particularly beneficial in prenatal care settings and in communities with emerging syphilis outbreaks. 3,5 2 Syphilis POCTs can be administered by trained individuals in a variety of settings Pointofcare tests for syphilis that provide results in minutes can be performed in clinical, laboratory, and outreach settings.…”

“…3,4 Pointofcare tests may be particularly beneficial in prenatal care settings and in communities with emerging syphilis outbreaks. 3,5 2 Syphilis POCTs can be administered by trained individuals in a variety of settings Pointofcare tests for syphilis that provide results in minutes can be performed in clinical, laboratory, and outreach settings. [3][4][5] Fingerstick specimens can be used; results are read according to the manu facturer's instructions.…”