Treponema pallidum hemagglutination for confirmation of syphilis in Cuba

[摘要] Introduction: syphilis is a reemerging sexually transmitted infection in industrial and developing countries. It remains a health problem in Cuba and for the serological diagnosis, nontreponemal tests are the only used. Treponema pallidum hemagglutination (TPHA) is used exclusively in the National Laboratory of Spirochetes at "Pedro Kourí" Institute of Tropical Medicine (LNE-IPK), so it was decided to decentralize the conduction of this test, in order that the provincial laboratories throughout the country can perform it as a confirmatory test. Objective: to show the results of applying the TPHA to confirm syphilis. Methods: one thousand fifteen serum samples with reactive results in the VDRL/RPR(venereal disease research laboratorios/rapid plasma reagin) (622 from pregnant women, 25 from postpartum women and 368 from other individuals) were studied in 11 provinces. TPHA was applied to all sera in the provincial laboratories and later in the LNE-IPK as quality control. From these last results, the percentage of serological confirmation, the rates of false positive results according to the VDRL/RPR and the specific rate of false positives by trimester of pregnancy were all determined. Results: the quality control performed in the LNE-IPK showed discordance values among the results of 0 to 30 %. Syphilis was confirmed in 65% of the samples. Of the reactive VDRL/RPR results, 33.9 % were false positives in pregnant women, 20.0 % in puerperas and 38.3 % in other individuals. The first and third trimesters of pregnancy contributed a lot to this type of result. Conclusions: these results support the need of including nontreponemal and treponemal tests in the serological diagnosis of syphilis in Cuba, mainly for pregnant women.

[学科分类] 传染病学

[关键词] syphilis;TPHA;false positive results;diagnosis