The CDC and others have recommended TP-PA
assays for confirmation, and the high analytical sensitivity of this assay suggests that it would be a suitable choice in a wide range of situations.
To address potential reverse screen FPs, the CDC suggests confirmation of discordant samples using the TP-PA
reactivity is necessary to rule out an FP.
To evaluate reverse sequence screening in populations with high and low syphilis prevalence and to evaluate the use of TP-PA and FTA-ABS tests for identifying false-positive EIA/CIA screening tests, CDC analyzed syphilis screening data from five clinical laboratories.
those with negative nontreponemal test results), and 3) nonreactive confirmatory TP-PA or FTA-ABS tests among discordant sera.
6%) were nonreactive by TP-PA or FTA-ABS testing, suggesting that the initial EIA/ CIA result was a false-positive.
If test results are discordant, the specimen should be tested reflexively using the TP-PA test as a confirmatory treponemal test.
Based on published sensitivity and specificity data, the TP-PA test currently is considered to be the most suitable confirmatory treponemal test (10).
Previously untreated patients with discordant sera and a reactive TP-PA should be treated according to CDC's 2010 STD Treatment Guidelines.
La sensibilidad de la prueba TP-PA
, utilizada como primera eleccion para el tamizaje, fue de 86% (intervalo de confianza de 95% [IC95%]: 78 a 92%), aunque fue menor en personas seropositivas al VIH que en los seronegativos (55% frente a 77%; P = 0,05).
pallidum EIA test, TP-PA
test, and FTA-ABS test, can produce reactive results for life, even after adequate treatment for syphilis.
For instance, in a recent evaluation of 39 dark-field confirmed syphilis cases, VDRL was reactive in 30 (77%) whereas TP-PA was positive in 37 (95%).
An evaluation of the relative sensitivities of VDRL and TP-PA among patients with darkfield-confirmed primary syphilis [Abstract 0641].