Objective: The aim of the study was to quantify detection of syphilis with the DETERMINE Syphilis test versus single or combined treponemal/cardiolipin tests in a primary care setting.
Methods: A total of 107 positive DETERMINE results obtained in 1898 samples were compared with combined Rapid Plasma Reagin/Venereal Disease Research Laboratory and Fluorescent Treponemal Antibody Absorption results. True-positive tests were defined as either serological confirmation by either cardiolipin and/or specific treponemal positive results at diagnosis or at 1-week follow-up or signs and symptoms classically compatible with syphilis, which resolved completely and rapidly on administration of a single-dose benzathine penicillin G. All positive cases showed a sustained positive result in the DETERMINE Syphilis test at follow-up. False-positive tests with DETERMINE Syphilis test were defined as being unconfirmed by cardiolipin and specific treponemal positive tests at baseline and negativity in the follow-up period.
Results: A total of 107 patients were positive with the DETERMINE Syphilis TP test. Of those, 20 (18.7%) were negative in both cardiolipin and specific treponemal positive tests. Fourteen (13.1%) were negative in cardiolipin tests but positive in specific treponemal positive tests. Of those patients with a positive DETERMINE Syphilis TP test result but with negative dual confirmation, 15 were shown to be true-positive results by fulfilling one or more of the aforementioned criteria, making this rapid syphilis test 14.0% superior in the diagnosis of syphilis than combined conventional tests. Compared with the use of single cardiolipin tests, the DETERMINE Syphilis TP test detected 29 more cases (27.1%).
False-positive tests with DETERMINE Syphilis TP test occurred in 5 patients (0.26%) of all those tested.
Conclusions: The DETERMINE Syphilis test is superior to treponemal and cardiolipin tests alone or in combination in the detection of syphilis in primary care.
From the *Centro Médico Open House; and †Laboratorios Ruiz Falcó, Madrid, Spain.
Reprints: Stephen Chapman, BMedSci, BM, BS, Centro Médico Open House, Calle Atocha 117, 1, izq., 28004 Madrid, Spain. E-mail: email@example.com.
The authors declare no conflict of interest. The authors have no professional link to the manufacturers mentioned in this paper and received no finance for this study.
Dr Stephen Chapman conceptualized and designed the study, performed clinical patient assessment, analyzed data, drafted the manuscript, and was responsible for the final approval. Pablo Fernández Cañadas and Dr José Martín Lluch were responsible for conceptualization of the study, performed patients' syphilis tests, contributed to the critique of the manuscript, and gave final approval.