To evaluate the diagnostic value of treponema pallidum particle agglutination (TPPA) and toludine red unheated serum test (TRUST) for the therapeutic effects of early syphilis.

Syphilis patients visited the Dermatological Department of Beijing Tongren Hospital, Capital Medical University from January 2012 to October 2016 were recruited, including 189 patients with early syphilis and 39 patients without clinical symptoms but with risky behavior within 3 months. Serum samples were tested by TPPA and TRUST respectively before treatment and at month 3, 6, 12 after treatment. Comparison between groups was done by χ² test.

Serum TPPA results of 228 patients with early syphilis prior to the treatment and within 12 months after treatment were all positive. Before treatment, TRUST tests results of 225 patients were positive, and 156 patients turned negative after 12 months of treatment with the negative conversion rate of 69.3%. The TRUST titer ≤1∶4 before treatment was defined as low-titer group, and ≥1∶8 before treatment was defined as high-titer group. There were 93 patients in the low-titer group, including 3 patients with negative results, and 90 patients with titer 1∶1—1∶4. There were 135 patients in the high-titer group. Twenty-seven patients achieved TRUST negative conversion after 3 months of treatment, among which 19.35%(18/93) with the negative conversion rate in the low-titer group and 6.67%(9/135) in the high-titer group. The difference between the two groups was statistically significant (χ²=7.10, P<0.01). Sixty-two patients converted into negative results of TRUST assay after 6 months of treatment, including 36.56%(34/93) in the low-titer group and 11.85%(16/135) in the high-titer group whose titer of 1∶1—1∶4, and 6.45%(6/93) in the low-titer group and 4.44%(6/135) in the high-titer group whose titer ≥1∶8 turned negative. The difference between the two groups was statistically significant (χ²=17.10, P<0.01). There were 67 patients converted negative detected by TRUST assay after 12 months of treatment, including 23.66%(22/93) in the low-titer group with titer of 1∶1—1∶4 and 14.81%(20/135) in the high titer group, and 1.08%(1/93) in the low-titer group and 17.78%(24/135) in the high-titer group whose titer ≥1∶8 were turned negative. The difference between the two groups was not statistically significant (χ²=1.51, P>0.05).

Serological tests combined with clinical signs can accurately diagnose early syphilis and evaluate the therapeutic effects.

Serology; Early syphilis; TRUST; Titer; Treatment