Improving the coverage and accuracy of syphilis testing: The development of a novel rapid, point-of-care test for confirmatory testing of active syphilis infection and its early evaluation in China and South Africa.
EClinicalMedicine. 2020 Jul; 24:100440.E

Abstract

BACKGROUND

Current point-of-care tests (POCT) for syphilis, based on the detection of Treponema pallidum (TP) total antibodies, have limited capacity in distinguishing between active and past/treated syphilis. We report the development and early evaluation of a new prototype POCT based on the detection of TP-IgA antibodies, a novel biomarker for active syphilis.

METHODS

The TP-IgA POCT (index test) was developed in response to the World Health Organisation (WHO) target product profile (TPP) for a POCT for confirmatory syphilis testing. Two sub-studies were conducted consecutively using 458 pre-characterised stored plasma samples in China (sub-study one, addressing the criteria for the WHO TPP), and 503 venous blood samples collected from pregnant/postpartum women in South Africa (sub-study two, addressing potential clinical utility). Performance of the index test was assessed against standard laboratory-based serology using a combination of treponemal (TPHA) and non-treponemal (rapid plasma reagin [RPR]) tests.

FINDINGS

In sub-study one, the index test demonstrated 96·1% (95%CI=91·7%-98·5%) sensitivity and 84·7% (95%CI=80·15-88·6%) specificity for identification of active syphilis (TPHA positive, RPR positive). It correctly identified 71% (107/150) samples of past-treated syphilis (TPHA positive, RPR negative). In sub-study two, the index test achieved 100% (95%CI=59%-100%) sensitivity for active syphilis and correctly identified all nine women with past syphilis.

INTERPRETATION

The TP-IgA POCT has met the WHO TPP for a POCT for diagnosis of active syphilis and demonstrated its potential utility in a clinical setting. Future studies are warranted to evaluate field performance of the final manufactured test.

FUNDING

Saving Lives at Birth: Grand Challenge for Development, Thrasher Research Fund, and the Victorian Government Operational Infrastructure Scheme.

Links

Publisher Full Text
ncbi.nlm.nih.gov
linkinghub.elsevier.com
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Authors+Show Affiliations

Pham MD
Burnet Institute, 85 Commercial Road, Melbourne, Victoria 3004, Australia. School of Public Health and Preventive Medicine, Monash University, Melbourne, Australia.
Wise A
Empilweni Services and Research Unit, Department of Paediatrics & Child Health, Rahima Moosa Mother and Child Hospital, School of Clinical Medicine, Faculty of Health Sciences, University of the Witwatersrand, South Africa.
Garcia ML
Burnet Institute, 85 Commercial Road, Melbourne, Victoria 3004, Australia.
Van H
Burnet Institute, 85 Commercial Road, Melbourne, Victoria 3004, Australia.
Zheng S
Burnet Institute, 85 Commercial Road, Melbourne, Victoria 3004, Australia.
Mohamed Y
Burnet Institute, 85 Commercial Road, Melbourne, Victoria 3004, Australia. School of Public Health and Preventive Medicine, Monash University, Melbourne, Australia.
Han Y
National Center for STD Control, China Center for Disease Control and Prevention, Nanjing, PR China. Chinese Academy of Medical Sciences Institute of Dermatology and Hospital of Skin Diseases, Nanjing, PR China.
Wei WH
National Center for STD Control, China Center for Disease Control and Prevention, Nanjing, PR China. Chinese Academy of Medical Sciences Institute of Dermatology and Hospital of Skin Diseases, Nanjing, PR China.
Yin YP
National Center for STD Control, China Center for Disease Control and Prevention, Nanjing, PR China. Chinese Academy of Medical Sciences Institute of Dermatology and Hospital of Skin Diseases, Nanjing, PR China.
Chen XS
National Center for STD Control, China Center for Disease Control and Prevention, Nanjing, PR China. Chinese Academy of Medical Sciences Institute of Dermatology and Hospital of Skin Diseases, Nanjing, PR China.
Dimech W
National Serology Reference Laboratory, Melbourne, Australia.
Braniff S
National Serology Reference Laboratory, Melbourne, Australia.
Technau KG
Empilweni Services and Research Unit, Department of Paediatrics & Child Health, Rahima Moosa Mother and Child Hospital, School of Clinical Medicine, Faculty of Health Sciences, University of the Witwatersrand, South Africa.
Luchters S
Burnet Institute, 85 Commercial Road, Melbourne, Victoria 3004, Australia. School of Public Health and Preventive Medicine, Monash University, Melbourne, Australia. Department of Population Health, Aga Khan University, Nairobi, Kenya.
Anderson DA
Burnet Institute, 85 Commercial Road, Melbourne, Victoria 3004, Australia. Nanjing BioPoint Diagnostic Technology, Nanjing, PR China.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

32637904