No abstract available.
Human ; Korea ; Quality Control ; Syphilis Serodiagnosis/*methods/standards

BACKGROUND: We evaluated the performance and false positive rate of Mediace RPR test (Sekisui, Japan), a newly introduced nontreponemal test using a chemistry autoanalyzer. METHODS: The sensitivity of Mediace RPR test was analyzed using sera from 50 patients with syphilis in different stages (8 primary, 7 secondary, and 35 latent), 14 sera positive with fluorescent treponemal antibody absorption (FTA-ABS) IgM, and 74 sera positive with conventional rapid plasma regain (RPR) card test (Asan, Korea) and also positive with Treponema pallidum hemagglutination (TPHA) test or FTA-ABS IgG test. The specificity was analyzed on 108 healthy blood donors. We also performed RPR card test on 302 sera that had been tested positive with Mediace RPR test and also performed TPHA or FTA-ABS IgG test to analyze the false positive rate of Mediace RPR test. A cutoff value of 0.5 R.U. (RPR unit) was used for Mediace RPR test. RESULTS: Mediace RPR test on syphilitic sera of different stages (primary, secondary, and latent stages) and FTA-ABS IgM positive sera showed a sensitivity of 100%, 100%, 82.9% and 100%, respectively. Among the 74 sera positive with conventional RPR card test and TPHA or FTA-ABS IgG test, 55 were positive with Mediace test. The specificity of Mediace RPR test on blood donors was 97.2%. Among the 302 sera positive with Mediace RPR test, 137 sera (45.4%) were negative by RPR card and TPHA/FTA-ABS IgG tests. CONCLUSIONS: Although the sensitivities of Mediace RPR were good for primary and secondary syphilis, due to its high negative rate of Mediace RPR over the conventional RPR positive samples, further studies are necessary whether it can replace conventional nontreponemal test for screening purpose. Moreover, in view of the high false positive rate, positive results by Mediace RPR test should be confirmed with treponemal tests.
Autoanalysis/methods ; False Positive Reactions ; Humans ; ROC Curve ; Sensitivity and Specificity ; Syphilis/*diagnosis ; Syphilis Serodiagnosis/*methods

BACKGROUND: We compared two automated Rapid Plasma Reagin (RPR) assay kits with a manual RPR assay kit to evaluate the possibility of using the two automated RPR assays as an alternative to the manual RPR assay for a quantitative monitoring. METHODS: One hundred eighty-five samples were analyzed, including 16 sera from patients with primary, secondary, and latent syphilis. Measured RPR unit (R.U.) values of two automated RPR assay kits, Mediace RPR (Sekisui Chemical Co., Ltd, Japan) and HBi Auto RPR (HBI Co., Ltd, Korea), were compared with the RPR titers of Macro-Vue RPR card test (Becton Dickinson BD Microbiology systems, USA). As a confirmatory test, Anti-Treponema pallidum EUROLINE WB (IgG) and Anti-Treponema pallidum EUROLINE WB (IgM) (Euroimmun, Germany) were used. RESULTS: There was a prozone effect with Mediace RPR at RPR titer (card test) of 1:16, but not with HBi Auto RPR. The R.U. values of the two automated RPR assays did not show proportional increase to the RPR titer. Agreement between manual RPR and two automated RPR assay kits, Mediace RPR assay and HBi Auto RPR assay, were 83.8% and 83.2%, respectively. CONCLUSIONS: The two automated RPR assay kits could not be used as an alternative to manual RPR test for quantitative analysis of RPR titer. As Mediace RPR shows a prozone effect at relatively low RPR titer, caution is needed in the interpretation of the measured values.
Automation ; Female ; Humans ; Male ; Reagent Kits, Diagnostic ; Reagins/*blood ; Sensitivity and Specificity ; Syphilis/*diagnosis ; Syphilis Serodiagnosis/*methods ; Treponema pallidum

Syphilis, a chronic bacterial infection caused by the spirochete Treponema pallidum subsp. pallidum, remains a public health concern worldwide. Syphilis control is largely dependent upon early identification and prompt treatment. The diagnosis of syphilis is mainly based on laboratory tests, especially serology and dark-field microscopy. In recent years, recombinant Treponema pallidum antigen-based rapid tests, polymerase chain reaction, and immunoglobulin M antibody detection have also shown certain sensitivities and specificities for syphilitic patients at different stages.
Antigens, Bacterial ; blood ; Humans ; Immunoglobulin M ; blood ; Polymerase Chain Reaction ; methods ; Sensitivity and Specificity ; Syphilis ; blood ; diagnosis ; Syphilis Serodiagnosis ; Treponema pallidum ; immunology ; isolation & purification

OBJECTIVETo clone tpn17 and tpn47 genes of Treponema pallidum and then construct their prokaryotic expression systems,to establish ELISAs based on rTpN17 and rTpN47 as antigens and to evaluate the sensitivity and specificity of the ELISAs for detection of serological diagnosis of syphilis.

METHODSThe whole length of tpn17 and tpn47 genes was amplified by PCR and then their prokaryotic expression systems were constructed. SDS-PAGE was used to measure the expression of the target recombinant proteins rTpN17 and rTpN47. Ni-NTA affinity chromatography was applied to extract rTpN17 and rTpN47, while Western blot was performed to determine the specific immunoreactivity of rTpN17 and rTpN47. By using rTpN17 and rTpN47 as the coated antigen, respectively, ELISAs (rTpN17-ELISA and rTpN47-ELISA) were established to detect serum samples from 200 healthy individuals, 25 RA patients, 17 SLE patients and 211 syphilis patients. The detection effects of the ELISAs were compared to those of TRUST and TPHA.

RESULTThe sequence similarity of the cloned tpn17 and tpn47 genes was 100 % compared with the corresponding sequences in GenBank. The expression outputs of rTpN17 and rTpN47 were approximately 37.2 % and 26.8 % of the total bacterial proteins, respectively. Both the extracted rTpN17 and rTpN47 could take place remarkable conjugation reactions to the sera with positive antibody against Treponema pallidum.The positive detection rate of TPHA (99.1%) was the highest (P<0.001). The positive detection rates of rTpN17-ELISA (85.3 %) and rTpN47-ELISA (84.3 %) were similar (P>0.05). The positive detection rates of TRUST (72.5 %) was lower than that of rTpN17-ELISA (P=0.001) but similar to that of rTpN47-ELISA (P=0.014). The detection results of all the serum samples from healthy individuals, RA patients and SLE patients were negative, whereas 7.1 % (3/42) of the samples from RA or SLE patients were positive.

CONCLUSIONrTpN17 and rTpN47 are still maintaining their original immunoreactivity. The ELISAs using rTpN17 or rTpN47 as the antigen are rapid, simple and convenient, higher sensitivity and specificity methods for serological screening and detection of syphilis.

Antibodies, Bacterial ; Antigens, Bacterial ; Blotting, Western ; Enzyme-Linked Immunosorbent Assay ; methods ; Female ; Humans ; Male ; Syphilis ; diagnosis ; Syphilis Serodiagnosis ; Treponema pallidum ; chemistry ; immunology ; isolation & purification

OBJECTIVETo investigate the incidence of seroresistance of syphilis and analyze its relevant factors.

METHODSThe clinical data of 131 patients with syphilis were retrospectively analyzed. The incidence of seroresistance was investigated and the correlation between seroresistance and factors including age, gender, original titer, disease course, and medications were analyzed.

RESULTSThe incidence of seroresistance was not significantly different among patients with different ages and genders, but was significantly different among patients with different disease courses, antibody titers, and medications. Patients with a baseline serum rapid plasma reagin (RPR) titer of greater than 1: 8, a latent course, or a macrolide therapy history had higher incidences of seroresistance (i. e., 61%, 45.6%, and 72.7% respectively) than those who had a lower RPR titer, a primary course, or a benzathine penicillin therapy history.

CONCLUSIONSyphilis patients with a high baseline RPR titer, a latent course, and a macrolides therapy are prone to be seroresistant.

Adolescent ; Adult ; Aged ; Female ; Humans ; Macrolides ; therapeutic use ; Male ; Middle Aged ; Reagins ; blood ; Syphilis ; blood ; diagnosis ; drug therapy ; immunology ; Syphilis Serodiagnosis ; methods ; Young Adult

BACKGROUND: Current status of external quality assessment (EQA) of laboratory tests for syphilis in Korea was analyzed to find out the problems that should be improved in the future. METHODS: Based on the data from the external quality assessment program performed twice a year by the Immunoserology Subcommittee of the Korean Association of Quality Assurance for Clinical Laboratory from the year 2004 to 2006, discordance rates were analyzed according to the test method and commercial kit used. RESULTS: Among the laboratories participating in the EQA program for syphilis test, about 90% of them used non-treponemal tests and about 55% treponemal tests. The non-treponemal tests included RPR (rapid plasma reagin) and VDRL tests used in 88% (363/412) and 11% (45/412), respectively, of the laboratories. The discordance rates were 2.2% for RPR test and 3.6% for VDRL. For the treponemal tests, Treponema pallidum hemagglutination assay (TPHA) was used in 60-76% and Immunochromatography assay (ICA) in about 30% of the laboratories in 2006. A high discordance rate of over 10% was reported in both TPHA and in ICA methods, possibly due to a low titer (1:1 in VDRL) of EQA samples in 2005. Analysis of the accumulated data from year 2004 to 2006 showed that the discordance rates of TPHA, ICA, and FTA-ABS were 4.6%, 3.7%, and 2.7%, respectively. CONCLUSIONS: For syphilis tests, RPR test, TPHA, and ICA are mainly used in Korea. A high discordance rate is still reported in TPHA and ICA, especially when testing samples with a low titer. Further analysis of data and education of laboratory personnel are needed for the improvement of the EQA program.
Enzyme-Linked Immunosorbent Assay ; False Positive Reactions ; Fluorescent Treponemal Antibody-Absorption Test ; Humans ; Korea ; Quality Control ; Reagent Kits, Diagnostic ; Syphilis/*diagnosis ; Syphilis Serodiagnosis/methods/*standards ; Treponema Immobilization Test

BACKGROUND: The aim of the study was to establish a new syphilis test algorithm using Architect Syphilis TP (Abbott Japan, Japan: AST), a fully automated treponemal antibody test, as a screening test in a university hospital laboratory. We evaluated performance characteristics of AST in various patient groups. METHODS: A total of 1,357 serum samples obtained from patients at a university hospital from June to August, 2008 were categorized into checkup, preoperative, other diseases, diagnosis (clinically suspected of syphilis), and follow up groups. We compared the results of AST with those of RPR (N=1,276) or Treponema pallidum hemagglutination assay (TPHA, N=81). Samples with discrepant results between RPR or TPHA and AST were retested by fluorescent treponemal antibody absorption test (FTA-ABS) and all patients' clinical records were thoroughly reviewed. RESULTS: The positive rate of AST was significantly higher than that of RPR in preoperative and other diseases groups and was the same as that of RPR in diagnosis group. There were no significant differences in check up and follow up groups. The results of AST showed 97.4% (1,243/1,276) and 97.5% (79/81) concordance rates with those of RPR and TPHA, respectively. Among 26 RPR-AST discrepant and FTA-ABS confirmed cases, there were 20 RPR false-negatives, 4 RPR false-positives, 1 AST false-negative, and 1 AST false-positive. CONCLUSIONS: Based on the results and literature review, we established a new syphilis test algorithm using AST as a screening test, which would be helpful for detection of more syphilis patients including latent infections.
Adolescent ; Adult ; Aged ; Aged, 80 and over ; Algorithms ; Autoanalysis ; Child ; Child, Preschool ; False Positive Reactions ; Female ; Fluorescent Treponemal Antibody-Absorption Test/methods ; Hemagglutination Tests/methods ; Humans ; Male ; Middle Aged ; Reagent Kits, Diagnostic ; Sensitivity and Specificity ; Syphilis/*diagnosis ; Syphilis Serodiagnosis/*methods

OBJECTIVETo construct the prokaryotic expression systems of tpnl7 and tpn47 genes and tpn17-tpn47 fusion of Treponema pallidum, and to establish ELISAs based on rTpN17, rTpN47 and rTpN17-TpN47 as antigens to evaluate the sensitivity and specificity of the ELISAs for detection of serological diagnosed syphilis.

METHODStpn17 and tpn47 genes were amplified and cloned by routine molecular biological methods. PCR with linking primers was used to construct artificial fusion gene tpn17-tpn47. The prokaryotic expression systems of the genes were then constructed. SDS-PAGE was used to measure the expression of the target recombinant proteins rTpN17, rTpN47 and rTpN17-TpN47. Ni-NTA affinity chromatography was applied to extract the three recombinant proteins, while Western blot was performed to determine their immunity. Using rTpN17, rTpN47 and rTpN17-TpN47 as the coated antigens, ELISAs (rTpN17-ELISA, rTpN47-ELISA and rTpN17-TpN47- ELISA) were established to detect serum samples from 200 healthy individuals, 25 RA patients, 17 SLE patients and 419 syphilis patients. Results of the ELISAs were compared to those with TRUST and TPHA.

RESULTSThe sequence similarities of the cloned tpnl7 and tpn47 genes and the constructed tpn17-tpn47 fusion gene were 100%, compared with the corresponding sequences in GenBank. The expression outputs of rTpN17, rTpN47 and rTpN17-TpN47 were 37.2%, 23.3% and 29.8% of the total bacterial proteins, respectively. Each of the three purified recombinant proteins showed a single fragment in gel after electrophoresis, and could take place remarkable conjugation reactions to the positive sera from syphilis patients. The detection results of rTpN17-ELISA, rTpN47-ELISA and rTpN17-TpN47-ELISA were negative for the serum samples from healthy individuals, RA and SLE patients, while presented 84.4%, 82.3% and 98.1% positive detection rates for the serum samples from syphilis patients. The positive detection rates of rTpN17-ELISA and rTpN47-ELISA were lower than that of TPHA (P<0.01), while the positive detection rate of rTpN17-TpN47-ELISA was similar to that of TPHA (P>0.05). All the positive detection rates from ELISA tests were higher than that of TRUST (71.4%).

CONCLUSIONrTpN17-ELISA, rTpN47-ELISA and especially rTpN17-TpN47-ELISA established in this study were of great hope as it was rapid, simple, convenient, safe, with high sensitivity and specificity for serological screening and detection of syphilis.

Bacterial Proteins ; biosynthesis ; genetics ; Cloning, Molecular ; Enzyme-Linked Immunosorbent Assay ; methods ; Genes, Bacterial ; Humans ; Recombinant Fusion Proteins ; biosynthesis ; genetics ; Sensitivity and Specificity ; Syphilis ; diagnosis ; Syphilis Serodiagnosis ; methods ; Treponema pallidum ; genetics

OBJECTIVETo investigate the application value of toluidine red unheated serum test (TRUST), treponema pallidum enzyme-linked immunosorbent assay (TP-ELISA) and treponema pallidum particle agglutination assay (TPPA) in the serologic diagnosis of syphilis.

METHODSWe collected serum samples from 12 622 inpatients, 2 253 outpatients and 1 500 subjects in the medical examination center, and screened them by TRUST and TP-ELISA, followed by quantitative tests using TRUST and TPPA.

RESULTSAmong the 16 375 cases, clinically diagnosed syphilis was confirmed in 384, with a positive rate of 100% either by TRUST (1:2 -1 :16) or TPPA (1:80 - 1:2 560), and 92.2% by TP-ELISA.

CONCLUSIONTP-ELISA and TRUST should be simultaneously used for syphilis screening, but not TP-ELISA alone, and the results should be confirmed by TPPA. The combination of the three methods plays a valuable role in reducing the misdiagnosis and missed diagnosis, and contributes to the early and accurate diagnosis of syphilis.

Adolescent ; Adult ; Aged ; Aged, 80 and over ; Child ; Child, Preschool ; Enzyme-Linked Immunosorbent Assay ; methods ; Humans ; Infant ; Infant, Newborn ; Middle Aged ; Syphilis ; blood ; diagnosis ; Syphilis Serodiagnosis ; methods ; Treponema pallidum ; Young Adult