CDC recommends the traditional option because:
- 56.7% of specimens with a reactive EIA/CIA screening test had a nonreactive nontreponemal (RPR) test in a review of 5 studies comparing the two methods
- High number of discordant results between RPR and EIA/CIA indicate false positive reactions for current infections
- 31.6% of the nonreactive confirmatory treponemal tests were negative indicating a high number of false positives in these 5 studies
- When testing low prevalence populations, the percentage of patients with nonreactive screening treponemal tests was 2.9 times that of the high-prevalence population
- CDC finds the traditional algorithm performs better in identifying persons with active infection
- Traditional sequence of testing reduces the number of false positives results when the population tested has low prevalence
- If EIA/CIA tests are performed first, CDC recommends positives be tested by RPR; If the RPR is negative then test by TP-PA
- FTA-ABS is not recommended because it has lower specificity and sensitivity, requires a dedicated fluorescent microscope and well-trained personnel to perform it
