Table 1.

Clinical data and results of traditional and reverse syphilis screening algorithms for patients with a positive screening result (n = 15)

Patient	Traditional algorithma		Reverse algorithma			Interpretationb	Reason for testingc
	RPR (titer)	TP-PA	BioPlex	RPR (titer)	TP-PA
1	+ (128)	+	+	+ (128)	+	Active syphilis (treated)	HIV, neurosyphilis
2	+ (1)	+	+	+ (1)	+	Past, treated syphilis	Past syphilis
3	+ (1)	+	+	+ (1)	+	Past, treated syphilis	HIV, neurosyphilis
4	+ (1)	+	+	+ (1)	+	Past, treated syphilis	HIV, past syphilis
5	−	N/A	+	−	+	Past, treated syphilis	STD screen
6	−	N/A	+	−	+	Past, treated syphilis	Pretransplant exam
7	−	N/A	+	−	+	Past, treated syphilis	Penile discharge
8	−	N/A	+	−	+	Latent syphilis (treated)	Immigration exam
9	−	N/A	+	−	+	Latent syphilis (treated)	Pretransplant exam
10	−	N/A	+	−	−	Falsely reactive IgG	Cognitive disorder
11	−	N/A	+	−	−	Falsely reactive IgG	Cognitive disorder
12	−	N/A	+	−	−	Falsely reactive IgG	Cognitive disorder
13	−	N/A	+	−	−	Falsely reactive IgG	Pretransplant exam
14	−	N/A	+	−	−	Falsely reactive IgG	Urinary incontinence
15	−	N/A	+	−	−	Falsely reactive IgG	Vaginal discharge

^aThe results of traditional and reverse syphilis screening algorithms are shown. The tests are abbreviated as follows: RPR, rapid plasma reagin; TP-PA, Treponema pallidum particle agglutination; BioPlex, BioPlex syphilis IgG immunoassay. The test results are shown as follows: +, reactive; −, nonreactive; N/A, not applicable. If the rapid plasma reagin test gave a reactive result, the reciprocal endpoint titer is provided in parentheses.

^bPatients that were treated as a result of testing are indicated in parentheses. An interpretation of “Past, treated syphilis” was based on provider documentation or patient communication of past treatment for syphilis.

^cSTD, sexually transmitted disease.