Comparison Of Different Detection Methodsf Or Syphilis Antibodies And Establishment Of Preliminary Screening Test

Background:Syphilis is a classic sexually transmitted diseases(STD)caused by Treponema pallidum(TP)infection.It has the characteristics of strong infectivity,long incubation period,systemic and global distribution,and is mainly transmitted through sexual contact,Placenta,blood and body fluids.According to survey data from the World Health Organization(WHO),approximately 12 million new syphilis patients are scattered around the world each year.In recent years,the syphilis infection rate in my country has shown an obvious upward trend.In 2018,the national syphilis incidence rate was as high as 35.6251/100,000,and the average annual increase in syphilis incidence rate in the past 10 years exceeded 13.37%.With such a high incidence of syphilis,to control its growing situation requires rapid diagnosis and treatment of syphilis.There are many types of syphilis laboratory tests,each with advantages and disadvantages.At present,serological tests are widely used in clinical diagnosis of syphilis and monitoring of efficacy.Serological testing methods for syphilis are mainly divided into two categories.One is the detection of specific antibodies for Treponema pallidum,including the Treponema pallidum partical assay(TPPA)and the Treponema pallidum-enzyme-linked immunosorbent assay(TP-ELISA),etc.Another is the detection of Treponema pallidum non-specific antibodies,including Rapid plasma reagin circle card test(RPR),etc.TPPA,TP-ELISA and RPR are all commonly used serological testing techniques for syphilis in laboratories.Among them,there is no uniform conclusion as to which test method to detect syphilis is fast,accurate,and easy to operate,and is suitable for the initial screening of clinical large-scale syphilis specimens.Objective :To explore the application value of Treponema pallidum partical assay(TPPA),Treponema pallidum enzyme-linked immunosorbent assay(TP-ELISA)and rapid plasma reagin ring card test(RPR)in the diagnosis of syphilis,and select the initial screening test suitable for clinical large-scale syphilis specimens.Methods:The serum of 389 patients(age 0-90 years)(removal of repeated hospitalization and re-examination cases)of syphilis in our hospital’s outpatient and wards from September 2018 to September 2019 were usedas research samples,of which 136 males(34.96%)and 253 females(65.04%).Serum samples of all patients were tested by laboratory skilled personnel using TPPA,TP-ELISA and RPR three methods at the same time.If the test results of the same sample are inconsistent,the TPPA result is used as the gold standard.A retrospective analysis of the obtained test results was conducted to compare the positive rate,sensitivity and specificity of the three methods and the distribution characteristics of the number of positive cases analyzed by gender and age.Results:1.The test results of 389 syphilis serum samples showed that the positive rates of syphilis screening by TPPA,TP-ELISA and RPR were 84.58%(329 cases),86.12%(335 cases)and 70.18%(273 cases).Taking TPPA as a confirmation test,the sensitivity of TP-ELISA was 99.09%,the specificity was 90.00%,and the coincidence rate was 98.21%;the sensitivity of RPR was 77.20%,the specificity was 86.67%,and the coincidence rate was 93.04%.The positive rate of TP-ELISA was the highest,and the positive rates of the three detection methods were significantly different and statistically significant(P <0.05).Among them,there was no significant difference in the positive rates of TP-ELISA and TPPA(P>0.05),and the positive rates of RPR and TP-ELISA,RPR and TPPA were significantly different and statistically significant(P<0.05;P <0.05).2.Of the 389 syphilis test specimens,136 were male(34.96%)and 253 were female(65.04%),of which 92 were male,with a positive rate of 23.65%,243 were female,with a positive rate of 62.47%.The positive rate of females is higher than that of males,and the ratio of males to females is 1: 2.6.The positive rate of different genders is significantly different and statistically significant(P <0.05).3.The positive rates of syphilis in different age groups detected by TPPA,TP-ELISA and RPR methods were compared respectively.The results showed that the positive rates of the three methods in different age groups were significantly different and statistically significant(P <0.05;P <0.05;P <0.05),of which 15-30 years old and 60-75 years old had a higher positive rate.Conclusion:1.In this study,by comparing the three syphilis detection tests of TPPA,TP-ELISA and RPR,a screening method for syphilis was obtained: TP-ELISA was used for the initial screening of syphilis,andthe samples with positive screening results were then used for RPR detection,and when the RPR result is uncertain,TPPA is used as a confirmation test.2.The infection rate of syphilis is different in different genders,and women have a higher positive rate than men.3.The infection rate of syphilis is different in different age groups,and the positive rate were higher in the 15-30 years old and 60-75 years old.