Single-test syphilis serology: A case of not seeing the forest for the trees.

INTRODUCTION: There have been few empirical studies for diagnostic test accuracy of syphilis using a sequence of rapid tests in populations with low prevalence of syphilis such as pregnant women. This analysis describes syphilis test positivity frequency among pregnant women at an antenatal clinic in Zambia using a reverse-sequence testing algorithm for antenatal syphilis screening. METHODS: Between August 2019 and May 2023, we recruited 1510 pregnant women from a peri-urban hospital in Lusaka, Zambia. HIV positive and HIV negative women were enrolled in a 1:1 ratio. Blood collected at recruitment from the pregnant mothers was tested on-site for syphilis using a rapid treponemal test. Samples that tested positive were further tested at a different laboratory, with rapid plasma reagin using archived plasma. RESULTS: Of the total 1,421 sera samples which were screened with a rapid treponemal test, 127 (8.9%) were positive and 1,294 (91.1%) were negative. Sufficient additional samples were available to perform RPR testing on 114 of the 127 (89.8%) RDT positive specimens. Thirty-one (27.2%) of these 114 were reactive by RPR and 83 (72.8%) were negative, resulting in a syphilis overtreatment rate of 3 fold (i.e, 84/114). Insufficient sample or test kit availability prevented any testing for the remaining 89 (5.9%) participants. CONCLUSION: Use of only treponemal tests in low prevalence populations, like pregnant women, subjects individuals with non-active syphilis to the costs and possible risks of overtreatment. The use of the dual treponemal and non-treponemal tests would minimize this risk at some additional cost.

Factors influencing the positivity of diagnostic tests for congenital syphilis.

OBJECTIVE: The objective of this study was to analyze the factors that influence the positivity of treponemal and non-treponemal tests in cases of congenital syphilis. METHODS: This cross-sectional and correlational study was carried out from the analysis of the database of Disease and Notification Information System (SINAN, in Portuguese) using the data obtained through the Epidemiological Surveillance Group 29, with 639 notifications of congenital syphilis between 2007 and 2018. The data were analyzed by a descriptive and inferential analysis from logistic regression with a significance level of 5% (p≤0.05). RESULTS: The positivity of the treponemal test was higher by 4.5 times in infants living in rural areas and 19.6 times among those whose mothers obtained the diagnosis of syphilis after birth. The treponemal test showed positivity 3.2 times higher for the variable "having been diagnosed between 2007 and 2015" and 5.5 times higher for the variable "having been diagnosed with maternal syphilis in the postpartum period." CONCLUSION: This study shows that testing during prenatal care is essential for early diagnosis and prevention of syphilis complications.

A multi-country comparative study of two treponemal tests for the serodiagnosis of syphilis amongst men who have sex with men (MSM): Chemo-luminescent assay vs Treponema pallidum particle agglutination assay.

INTRODUCTION: International guidelines recommend routine screening for syphilis (aetiological agent: Treponema pallidum subspecies pallidum) amongst key populations and vulnerable populations using tests detecting treponemal and non-treponemal antibodies. Whilst treponemal tests have high sensitivities and specificities, they differ regarding subjective or objective interpretation, throughput and workload. Chemiluminescence immunoassays (CLIAs) are cost- and time-effective automated methods for detecting treponemal antibodies. The Treponema pallidum particle agglutination assay (TPPA) has been considered the "gold standard" treponemal assay, however, this includes a highly manual procedure, low throughput and subjective interpretation. The present multi-country study evaluated the ADVIA Centaur® Syphilis CLIA (Siemens Healthcare) assay compared to the reference SERODIA-TP·PA® (Fujirebio Diagnostics) for the serodiagnosis of syphilis amongst men who have sex with men (MSM). METHOD: 1,485 MSM were enrolled in Brighton (UK), Malta, and Verona (Italy) as part of a larger WHO multi-country and multi-site ProSPeRo study. Ethical approval was obtained. Serum was tested with the ADVIA Centaur® Syphilis CLIA assay and SERODIA-TP·PA®, in accordance with the manufacturers' instructions, for a first round of validation. A second round of validation was carried out for discrepant results that were additionally tested with both Western Blot (Westernblot EUROIMMUN®) and an Immunoblot (INNO-LIA, Fujirebio Diagnostics). Sensitivity, specificity, positive and negative predictive value (PPV and NPV), likelihood ratios (positive/negative), and the Diagnostic Odds Ratio (DOR)/pre-post-test probability (Fagan's nomogram) were calculated. RESULTS: Out of 1,485 eligible samples analysed in the first phase, the SERODIA-TP·PA® identified 360 positive and 1,125 negative cases. The ADVIA Centaur® Syphilis CLIA assay (Siemens) identified 366 positives, missclassifying one TPPA-positive sample. In the second phase, the ADVIA Centaur® Syphilis CLIA resulted in 1 false negative and 4 false positive results. Considering the syphilis study prevalence of 24% (95% CI: 22-26.7), The sensitivity of the ADVIA Centaur® Syphilis CLIA assay was 99.7% (95% CI: 98.5-100), and the specificity was 99.4% (95% CI: 98.7-99.7). The ROC area values were 0.996 (95% CI: 0.992-0.999), and both the PPV and NPV values were above 98% (PPV 98.1%, 95% CI: 96.1-99.2; NPV 99.9%, 95% CI: 99.5-100). CONCLUSIONS: The ADVIA Centaur® Syphilis CLIA assay showed similar performance compared to the SERODIA-TP·PA®. Considering the study is based on QUADAS principles and with a homogeneous population, results are also likely to be generalisable to MSM population but potentially not applicable to lower prevalence populations routinely screened for syphilis. The automated CLIA treponemal assay confirmed to be accurate and appropriate for routine initial syphilis screening, i.e. when the reverse testing algorithm is applied.

Neurosyphilis is characterized by a compartmentalized and robust neuroimmune response but not by neuronal injury.

BACKGROUND: Neurosyphilis is increasing in prevalence but its pathophysiology remains incompletely understood. This study assessed for CNS-specific immune responses during neurosyphilis compared to syphilis without neurosyphilis and compared these immune profiles to those observed in other neuroinflammatory diseases. METHODS: Participants with syphilis were categorized as having neurosyphilis if their cerebrospinal fluid (CSF)-venereal disease research laboratory (VDRL) test was reactive and as having syphilis without neurosyphilis if they had a non-reactive CSF-VDRL test and a white blood cell count <5/µL. Neurosyphilis and syphilis without neurosyphilis participants were matched by rapid plasma reagin titer and HIV status. CSF and plasma were assayed for markers of neuronal injury and glial and immune cell activation. Bulk RNA sequencing was performed on CSF cells, with results stratified by the presence of neurological symptoms. FINDINGS: CSF neopterin and five CSF chemokines had levels significantly higher in individuals with neurosyphilis compared to those with syphilis without neurosyphilis, but no markers of neuronal injury or astrocyte activation were significantly elevated. The CSF transcriptome in neurosyphilis was characterized by genes involved in microglial activation and lipid metabolism and did not differ in asymptomatic versus symptomatic neurosyphilis cases. CONCLUSIONS: The CNS immune response observed in neurosyphilis was comparable to other neuroinflammatory diseases and was present in individuals with neurosyphilis regardless of neurological symptoms, yet there was minimal evidence for neuronal or astrocyte injury. These findings support the need for larger studies of the CSF inflammatory response in asymptomatic neurosyphilis. FUNDING: This work was funded by the National Institutes of Health, grants K23MH118999 (S.F.F.) and R01NS082120 (C.M.M.).

Evaluation of Automated Processing of Electronically Reported Serological Tests for Syphilis Using Current and Historical Syphilis Results Compared With Traditional Reactor Grid Processing in Florida.

BACKGROUND: Syphilis in Florida increased 49% from 2016 to 2020. Moreover, many serological tests for syphilis (STS) do not indicate current infection. Traditionally, syphilis surveillance systems used reactor grids, a method for prioritizing STS for investigation based on age, nontreponemal titer, and/or sex. In 2022, Florida's sexually transmitted disease surveillance system implemented an automated method for processing electronically reported STS (eSTS), expanding upon the reactor grid, using an individual's current STS (treponemal and nontreponemal), treatment history, and historical STS results aiming for more efficiently processing eSTS. We compared the new method of processing eSTS results against the reactor grid and determined potential value in time/cost savings of this change. METHODS: All eSTSs (n = 4144) from January 2, 2023 to January 8, 2023, were compared by how the logic-based method processed test results versus how the reactor grid processed test results. Each method was compared using measurements of accuracy (e.g., sensitivity/specificity). Time and cost savings in eSTS processing were estimated. RESULTS: Using the surveillance case definition as reference, the accuracy of the logic-based method for processing eSTS was nearly double (82.3% vs. 43.6%), had greater specificity (79.0% vs. 33.0%), and increased positive predictive value (47.5% vs. 22.0%) when compared with the reactor grid method. Sensitivity (99.5% vs. 98.6%) and negative predictive value (99.9% vs. 99.2%) remained similar. The logic-based method is estimated to save 7783 hours annually (~$185,000). CONCLUSIONS: Processing eSTS based on current and historical STS results is significantly more accurate than using a reactor grid. Moreover, these improvements save time and resources that can be better allocated to other program prevention activities.

External quality assessment to support the WHO ProSPeRo study for the evaluation of two dual HIV/syphilis point-of-care tests in seven countries.

BACKGROUND: Sexually transmitted infections (STIs) such as syphilis and HIV remain to be a significant public health issue worldwide. Dual rapid point-of-care tests (POCTs) have shown promise for detecting antibodies to HIV and syphilis but have not been fully evaluated in the field. Our study supported the WHO ProSPeRo study on Sexually Transmitted Infection Point-of-Care Testing (STI POCT) by providing external quality assessment (EQA) for HIV and syphilis testing in reference laboratories and their associated clinical sites in seven countries. METHODS: HIV/syphilis serum liquid and dried tube specimen (DTS) panels were prepared by CDC. Liquid panels were distributed to the reference laboratories for three rounds of testing using commercially and locally available laboratory-based serological tests. DTS panels were sent to the clinical testing sites for 8 rounds of POC testing using the Abbott SD BIOLINE HIV/Syphilis Duo test (hereafter referred to as SD BIOLINE) and the Chembio Dual Path Platform (DPP) HIV-Syphilis assay. EQA panels were tested at CDC using the Rapid Plasma Reagin (RPR) test and the Treponema pallidum Particle Agglutination assay (TP-PA) for syphilis antibodies. Genetic Systems HIV-1/HIV-2 Plus O EIA, Geenius HIV Supplemental Assay and the Oraquick Advance HIV test were used to detect HIV antibodies in the EQA panels. Results from the reference laboratories and POCT sites were compared to those obtained at the CDC and a percentage agreement was calculated. RESULTS: Qualitative RPR and TP-PA performed at the reference laboratories demonstrated 95.4-100% agreement with CDC results while quantitative RPR and TP-PA tests demonstrated 87.7% and 89.2% agreement, respectively. A 93.8% concordance rate was observed for qualitative HIV testing in laboratories. EQA testing at clinical sites using dual tests showed 98.7% and 99.1% agreement for detection of HIV antibodies and eight out of 10 sites had > 95.8% agreement for syphilis testing. However, two clinical sites showed only 65.0-66.7% agreement for SD BIOLINE and 84.0-86.7% for DPP, respectively, for syphilis testing. CONCLUSIONS: Overall, laboratories demonstrated high EQA performance in this study. Both HIV/syphilis POCTs gave expected results in the clinic-based evaluations using DTS. However, testing errors were identified in a few testing sites suggesting the necessity for continuous training and monitoring the quality of POC testing.

Independent clinic-based evaluation of dual POCTs for screening for HIV and syphilis in men who have sex with men in Italy, Malta, Peru, and the United Kingdom.

INTRODUCTION: Globally, the incidence of HIV and syphilis can be reduced by the use of validated point of care tests (POCTs). As part of the WHO PRoSPeRo Network, we aimed to evaluate the performance, acceptability, and operational characteristics of two dual HIV/syphilis POCTs (Bioline HIV/Syphilis Duo (Abbott) and DPP® HIV-Syphilis assay (Chembio) for the screening of HIV and syphilis amongst men who have sex with men (MSM). METHOD AND ANALYSES: A cross sectional study of 2,577 MSM in Italy, Malta, Peru, and the United Kingdom (UK) presenting to seven clinic sites, were enrolled. Finger prick blood was collected to perform POCTs and results compared with standard laboratory investigations on venepuncture blood. Acceptability and operational characteristics were assessed using questionnaires. Diagnostic meta-analysis was used to combine data from the evaluation sites. RESULTS: Based on laboratory tests, 23.46% (n = 598/2549) of participants were confirmed HIV positive, and 35.88% of participants (n = 901/2511) were positive on treponemal reference testing. Of all participants showing evidence of antibodies to Treponema pallidum, 50.56% (n = 455/900) were Rapid Plasma Reagin (RPR) test reactive. Of HIV positive individuals, 60.62% (n = 354/584) had evidence of antibodies to T. pallidum, and of these 60.45% (n = 214/354) exhibited reactive RPR tests indicating probable (co)infection. For Bioline POCT, pooled sensitivities and specificities for HIV were 98.95% and 99.89% respectively, and for syphilis were 73.79% and 99.57%. For Chembio pooled sensitivities and specificities for HIV were 98.66% and 99.55%, and for syphilis were 78.60% and 99.48%. Both tests can detect greater than 90% of probable active syphilis cases, as defined by reactive RPR and treponemal test results. These dual POCTs were preferred by 74.77% (n = 1,926) of participants, due to their convenience, and the operational characteristics made them acceptable to health care providers (HCPs). CONCLUSIONS: Both the Bioline and the Chembio dual POCT for syphilis and HIV had acceptable performance, acceptability and operational characteristics amongst MSM in the PRoSPeRo network. These dual POCTs could serve as a strategic, more cost effective, patient and healthcare provider (HCP) friendly alternative to conventional testing; in clinical and other field settings, especially those in resource-limited settings.

CDC Laboratory Recommendations for Syphilis Testing, United States, 2024.

This report provides new CDC recommendations for tests that can support a diagnosis of syphilis, including serologic testing and methods for the identification of the causative agent Treponema pallidum. These comprehensive recommendations are the first published by CDC on laboratory testing for syphilis, which has traditionally been based on serologic algorithms to detect a humoral immune response to T. pallidum. These tests can be divided into nontreponemal and treponemal tests depending on whether they detect antibodies that are broadly reactive to lipoidal antigens shared by both host and T. pallidum or antibodies specific to T. pallidum, respectively. Both types of tests must be used in conjunction to help distinguish between an untreated infection or a past infection that has been successfully treated. Newer serologic tests allow for laboratory automation but must be used in an algorithm, which also can involve older manual serologic tests. Direct detection of T. pallidum continues to evolve from microscopic examination of material from lesions for visualization of T. pallidum to molecular detection of the organism. Limited point-of-care tests for syphilis are available in the United States; increased availability of point-of-care tests that are sensitive and specific could facilitate expansion of screening programs and reduce the time from test result to treatment. These recommendations are intended for use by clinical laboratory directors, laboratory staff, clinicians, and disease control personnel who must choose among the multiple available testing methods, establish standard operating procedures for collecting and processing specimens, interpret test results for laboratory reporting, and counsel and treat patients. Future revisions to these recommendations will be based on new research or technologic advancements for syphilis clinical laboratory science.

Advantages and limitations of current diagnostic laboratory approaches in syphilis and congenital syphilis.

INTRODUCTION: The reemergence of syphilis, especially congenital syphilis, presents a significant public health threat. Accurate diagnosis of syphilis depends on recognition of a constellation of symptoms, review of medical and sexual history, and multiple laboratory tests. While reliable, current tests for syphilis can be difficult to interpret, which can lead to delays in treatment. AREA COVERED: This review summarizes the major advantages and limitations of available diagnostic laboratory methods for syphilis, provides an update on recent advances in laboratory tools, and highlights the urgent need for coordinated efforts to create new tools to halt the resurgence of syphilis. EXPERT OPINION: In syphilis, the wide variety of short-lived signs and symptoms followed by periods of latency create diagnostic challenges. Currently available laboratory tests, when positive, require additional information to interpret (prior testing, treatment, and sexual history). Point-of-care tests that can rapidly and accurately detect both treponemal and non-treponemal antibodies would be a huge step toward reducing test turnaround time and time to treatment. Incorporating biological insights and technology innovations to advance the development of direct detection assays is urgently needed. A comprehensive coordinated effort is critical to stem the tide of rising syphilis in the United States and globally.

Evaluation of Three Automated Nontreponemal Rapid Plasma Reagin (RPR) Tests for the Laboratory Diagnosis of Syphilis.

Automated nontreponemal rapid plasma reagin (RPR) tests were recently introduced in the United States for syphilis testing and limited performance data are available. In collaboration with the Association of Public Health Laboratories, three public health laboratories (PHL) were chosen through a competitive selection process to evaluate the performance of three FDA-cleared automated RPR test systems: BioPlex 2200 Syphilis Total & RPR assay (Bio-Rad Laboratories), AIX 1000 (Gold Standard Diagnostics), and ASI Evolution (Arlington Scientific). Panels prepared at the CDC included: a qualitative panel comprised of 734 syphilis reactive/nonreactive sera; a quantitative panel of 50 syphilis reactive sera (RPR titer 1:64 to 1:1,024); and a reproducibility panel of 15 nonreactive and reactive sera (RPR titer 1:1 to 1:64). Panels were shipped frozen to the PHL and tested on the automated RPR systems following manufacturers' instructions. Prior test results were blinded to all laboratories. When compared to manual RPR (Arlington Scientific) performed at the CDC as a reference test, the qualitative panel results demonstrated an overall concordance of 95.9% for AIX 1000, 94.6% for ASI Evolution, and 92.6% for Bioplex RPR; quantitative panel showed within range titer of 2-fold for 94% of specimens for AIX 1000, 68% for ASI Evolution, and 64% for BioPlex RPR, and the reproducibility testing panel demonstrated point estimates ranging from 69 to 95%. Automated RPR instruments could reduce turnaround time and minimize interpretation errors. However, additional evaluations with more specimens could assist laboratories with implementing automated RPR tests and understanding their limitations.

Sensitivity and specificity of two investigational Point of care tests for Syphilis and HIV (PoSH Study) for the diagnosis and treatment of infectious syphilis in Canada: a cross-sectional study.

OBJECTIVES: Single-visit testing and treatment for syphilis can reduce follow-up visits. The objectives of this study were to evaluate the performance and treatment outcomes of two dual syphilis/HIV point-of-care tests (POCTs). METHODS: Participants aged 16 years and older were offered concurrent syphilis/HIV POCTs with fingerstick blood sampling using two extremely rapid (<5 minutes) devices (MedMira Multiplo Rapid TP/HIV test and INSTI Multiplex HIV-1/HIV-2/Syphilis Antibody Test). Those with positive POCT results were offered same-day syphilis treatment and linkage to HIV care. Nurses performed testing at two emergency departments, a First Nations community, a correctional facility, and a sexually transmitted infection clinic. POCT results were compared with those of standard serological testing. Sensitivity and specificity were calculated. RESULTS: Between August 2020 and February 2022, 1526 visits were completed. Both POCTs accurately identified participants with HIV (sensitivity, 100% [24 of 24]; 95% CI, 86.2-100%; specificity, 99.6% [1319 of 1324]; 95% CI, 99.1-99.8%), linking 24 HIV cases to care. Both tests were most sensitive with a rapid plasma reagin (RPR) of ≥1:8 dilutions (Multiplo: sensitivity, 98.3% [231 of 235]; 95% CI, 95.7-99.3%; specificity, 99.5% [871 of 875]; 95% CI, 98.8-99.8%; INSTI Multiplex: sensitivity, 97.9% [230 of 235]; 95% CI, 95.1-99.1%; specificity, 99.8% [873 of 875]; 95% CI, 99.2-99.9%) and least sensitive with non-reactive RPR (Multiplo: sensitivity, 54.1% [59 of 109]; 95% CI, 44.8-63.2%; specificity, 99.5% [871 of 875]; 95% CI, 98.8-99.8%; INSTI Multiplex: sensitivity, 28.4% [31 of 109]; 95% CI, 20.8-37.5%; specificity, 99.8% [873 of 875]; 95% CI, 99.2-99.9%). Eighty-five percent of participants with infectious syphilis were treated on the same day as the positive POCT result. DISCUSSION: Two extremely rapid (<5 minutes) dual syphilis/HIV POCTs showed excellent sensitivity and specificity for the diagnosis of active syphilis (RPR, ≥1:8 dilutions) and HIV and confirmed the ability to offer single-visit testing and treatment for syphilis and linkage to HIV care in diverse clinical settings.

A ruptured thoracic aortic aneurysm and the difficulties of confirming syphilis.

A 43-year-old woman died suddenly and was found at PM to have a ruptured thoracic aortic aneurysm. The endothelial surface of the aorta showed a 'tree-bark' appearance. Histology of the aneurysm wall showed a patchy, mainly perivascular, plasma cell infiltrate. Multiple spirochete-like organisms were identified on T. pallidum IHC. However, PM syphilis serology (screen including rapid plasma reagin (RPR) and T. pallidum particle agglutination (TPPA)) on femoral blood was negative. PCR testing on FFPE aortic wall tissue was negative. Further history revealed routine antenatal syphilis screening tests had been negative, no known history or risk of exposure to syphilis or other treponemes. This case raises the possibility of false negative syphilis testing. While acknowledged in RPR testing, with the modern testing regime using multiple methods, the rate of false negative results is now thought to be markedly reduced, and false positive results are a much greater problem in clinical medicine. The most common cause of false negative results is early in primary infection before an immune response has been mounted and in those patients that are immunocompromised. False negative results are also more often seen in tertiary syphilis, as in this case. Newer testing methods which include 16S rRNA sequencing have become available and early discussion with a microbiologist would be recommended. Strong macroscopic and microscopic suggestion of syphilis as the cause of the aneurysm makes it necessary to include the possibility of infection in the Post Mortem Report to Coroner as this will have implications for her sexual partners and children.

Understanding Utilization and Seroprevalence of Syphilis Tests in Local Clinics and Hospitals in Korea.

BACKGROUND: Diagnosis of syphilis, a sexually transmitted infection, can be based on clinical information and various combinations of results of both non-treponemal and treponemal assays. Because understanding a patient population is helpful for test utilization in the clinical laboratory, we aimed to investigate the results of syphilis serology tests requested from local clinics in Korea. METHODS: We retrospectively evaluated the syphilis serology test results of serum Rapid Plasma Reagin (RPR), Treponema pallidum latex agglutination (TPLA), RPR titer, and fluorescent treponemal antibody absorption (FTA-ABS) IgG, and IgM tests performed in Korean adults in the laboratory information system of Green Cross Laboratories. We investigated the patterns of syphilis serology test results and possible interpretation according to combinations of syphilis serology based on a traditional testing algorithm. RESULTS: During the one-year study period, 33,746 RPR tests were performed in Korean adults (7,622 men and 26,124 women) with a median age of 35.1 years (interquartile range 30.8 - 43.4 years). Among these RPR tests, 317 (0.9%) showed RPR+ results and were performed simultaneous with TPLA tests. Among these 317 patients, 187 (59.0%) had RPR+/TPLA+ results. Among 130 patients with RPR+/TPLA- results, FTA-ABS IgG and IgM were only tested in 15 (11.5%): 14 were IgG-/IgM-, and one who underwent only the IgM test showed a negative result (probably a biological false positive of RPR). Among 187 RPR+/TPLA+ patients, 60 (2.1%) had RPR titer ≥ 1:8, and 10 were FTA-ABS IgM+ (including weak reactive results probably due to current infection or rare biological false-positive). Among 121 patients with RPR+/TPLA+/RPR titer ≤ 1:4, 30 were tested for FTA-ABS IgG and/or IgM: the two FTA-ABS IgM+ (including weak reactive) patients had an RPR titer of 1:4. CONCLUSIONS: This study will help to understand patient populations and test utilization for syphilis serology test interpretation in clinical laboratories in Korea. Further studies are needed to investigate the clinical impact of test utilization of syphilis serology in Korea.

[Recent Advances in Laboratory Diagnosis of Syphilis]. / Sifilisin Laboratuvar Tanisinda Güncel Gelismeler.

Syphilis is a sexually transmitted disease caused by Treponema pallidum subsp. pallidum. This historical disease has diverse clinical manifestations making laboratory testing crucial for optimal patient management. Direct detection of T.pallidum by dark-field microscopy is possible when lesions are present. Culture of the bacteria is complex and not performed routinely. There is no well-validated commercially available polymerase chain reaction (PCR) test. Serological tests are currently the most common diagnostic methods adapted in clinical laboratories. They provide a presumptive diagnosis and used for screening, diagnosis, and follow-up of the treatment. They are divided into two groups, named as nontreponemal and treponemal tests and performed by the application of the traditional algorithm, the reverse sequence algorithm or European Centre for Disease Prevention and Control (ECDC) algorithm. The traditional algorithm starts with a nontreponemal test and a reactive result is confirmed with a treponemal test. In the reverse sequence algorithm, a treponemal test is used for screening and a reactive result is confirmed by a quantitative nontreponemal test. When the nontreponemal test is negative, a second different treponemal test preferably T.pallidum particle agglutination test (TPPA) is used. The ECDC algorithm recommends screening by a treponemal test such as T.pallidum enzym immunoassay (TP-EIA), T.pallidum chemiluminescence immunoassay (CIA) and if reactive, a reflex confirmatory treponemal test is performed. The treponemal tests become reactive a few weeks after infection and remain reactive even after successful treatment. The nontreponemal tests are used to assess disease activity and response to therapy. Serological tests have many limitations such as false-positivity, falsenegativity in various stages of the disease and also challenging difficulties when evaluating response to therapy. In recent years, rapid syphilis tests which are mostly treponemal-specific tests have been developed for high-prevalence populations in resource limited settings. There has been requirement for the utility of standart PCR and IgM testing in the diagnosis of congenital syphilis and neurosyphilis cases. In this review article, it was aimed to present the diagnostic tests, the algorithms, the correct indications for testing and interpretation of the test results to the likely corresponding clinical stage of the disease with in the perspective of recent advances.

Detection of Treponema pallidum in whole blood samples of patients with syphilis by the polymerase chain reaction.

Syphilis is caused by the bacterium Treponema pallidum. The diagnosis is based on clinical data and serological analysis; however, the sensitivity and specificity of such tests may vary depending on the type of test and stage of the infection. In order to overcome this premise, this study utilized the polymerase chain reaction (PCR) for the detection of T. pallidum DNA in whole blood samples of patients with syphilis. The blood samples from patients with or without symptoms of syphilis, but with positive results in enzyme-linked immunosorbent assay (ELISA), were included in this study. A venereal disease research laboratory (VDRL) test was performed for all collected sera samples. For PCR, the T. pallidum DNA was extracted from the collected blood samples and a specific primer set was designed to amplify 131 nucleotides of polA (Tp0105). The specificity of the primers was evaluated with the DNA of 17 different pathogens. From a total of 314 blood samples reactive in ELISA, 58.2% (183/314) of the samples were reactive in the VDRL test. In the PCR, 54% (168/314) of the ELISA-reactive samples were positive. In both tests (VDRL and PCR) 104 samples were positive. Of 104 positive samples for both tests, 71 were at the latent stage. Based on these results, it can be concluded that PCR with the designed set of primers can be utilized as a diagnostic method for T. pallidum detection in blood samples of patients with syphilis, especially those with latent infection. In addition, it can be utilized as a supplement for serological methods to improve the diagnosis of syphilis.

Performance evaluation of eight treponemal antibody tests in China.

In this study, the performance of 8 commercially available treponemal antibody tests was evaluated. Higher specificity was achieved in the automated chemiluminescence immunoassays(CIA assays) than enzyme-linked immunosorbent (ELISA) assays, but no significant differences were found in terms of the sensitivity levels. The levels of test sensitivity did not differ by HIV status and TRUST titer but did differ by clinical stage. The results of WB-IgG revealed that the level of antibodies against the 4 antigens showed an upward trend with the development of the clinical stages of syphilis, reaching a peak in tertiary syphilis and then decreasing. The present results supported the good performance of CIA tests used in the blood source screening of syphilis, which reduced the waste of plasma. The reaction intensities of anti-TP17 and TP47 antibodies in past treated syphilis samples were considerably weak and were expected to be used for monitoring the therapeutic effect of syphilis.

Stopping syphilis transmission in Arctic communities through rapid diagnostic testing: The STAR study protocol.

BACKGROUND: Intense transmission of syphilis has emerged in some Canadian Arctic communities despite screening and prevention efforts. The remoteness of most communities and limited diagnostic infrastructure yield long delays (≥14 days) between screening and treatment of cases. These hamper syphilis control efforts and may contribute to sustained transmission. Syphilis rapid diagnostic tests (RDTs) have been developed to make screening more accessible and to inform clinical decision-making within the same clinical encounter. These RDTs have been successfully deployed in several countries, but not yet in Canada. METHODS AND DESIGN: We describe the methodology of the "Stopping Syphilis Transmission in Arctic Communities Through Rapid Diagnostic Testing" (STAR) study, wherein the clinical and epidemiological impact of deploying a dual syphilis RDT in the context of ongoing transmission in Nunavut and Nunavik will be evaluated. In this prospective multisite field evaluation, sexually active individuals aged ≥14 years at risk for syphilis will be offered screening by an RDT at the point-of-care by non-laboratory trained registered nurses. Whole blood and serum specimens will be concurrently collected, when feasible, for rapid testing with an RDT containing both treponemal and non-treponemal components (Chembio DPP® Syphilis Screen & Confirm) and compared to laboratory-based reference testing according to a reverse sequence algorithm. The diagnostic accuracy of the RDT, using both whole blood and centrifuged serum specimens, will be validated under real-world conditions in remote Northern settings, outside of specialized laboratories. Additionally, screening-to-treatment time, case detection rates, and the number of infectious contacts averted by using the RDT relative to reference testing will be estimated. The impact of both diagnostic approaches on syphilis transmission dynamics will also be modeled. DISCUSSION: This study will provide much needed evidence for strengthening rapid responses to emerging syphilis outbreaks in remote Arctic regions, by supplementing traditional diagnostic strategies with an RDT to rapidly triage patients likely in need of treatment. These results will also inform the development and tailoring of future diagnostic strategies and public health responses to emerging outbreaks in the North.

When modern diagnostics is challenged by a historical disease: A case report.

RATIONALE: Syphilis is a bacterial, systemic infectious disease caused by Treponema pallidum spirochetes, which spread rapidly through the body affecting various organs. The term neurosyphilis (NS) refers to a CNS infection that can occur at any stage of the disease. The lack of a gold standard for the diagnosis of NS greatly hinders diagnosis, which must be based mainly on clinical assessment. PATIENT CONCERNS: A 58-year-old man reported dizziness and headache for a week and right-sided hearing impairment, with suspected transient cerebral ischemic attack. A month later he experience transient speech disturbance and suspected cerebral ischemic stroke. DIAGNOSIS: MRI showed fresh ischemic lesions with a diameter up to 10 mm in the deep brain structures on the left side and foci of subacute ischemia also in the deep structures and the brain stem. Cerebrospinal fluid examination showed positive Pandy's reaction, doubtful Noone-Apelt reaction, increased protein level and decreased glucose level. The reactive result of the USR test performed (VDRL) finally allowed the diagnosis of symptomatic CNS syphilis. INTERVENTIONS: Empiric treatment for bacterial meningitis was administered. The patient was transferred to the Department of Infectious Diseases for further treatment. OUTCOMES: The diagnosis has been confirmed at the Department of Infectious Diseases after repeating CSF analysis including VDRL and FTA-ABS. LESSON: Symptoms of NS are nonspecific, hence the diagnostic process is not straightforward. Despite the availability of modern diagnostic techniques, establishing a final diagnosis was challenging, but the patient ultimately received appropriate treatment. It is important to remember that syphilis is not only a disease known from history lessons but is still present in modern times and its incidence is increasing.

Annular rupioid secondary syphilis confined to the face.

OBJECTIVES: Syphilis is a sexually transmitted infection (STI) caused by treponema pallidum. Its rash usually affects the trunk and limbs extensively, including the palms and soles of the feet. Secondary syphilis confined to the face is extremely rare. METHODS: We report a case of annular rupioid secondary syphilis, which was misdiagnosed as verruca vulgaris. RESULTS: The patient's lesions were confined to the face and resembled oyster shells. Her serological tests results were positive for treponema pallidum particle agglutination assay (TPPA) and rapid plasma reagin (RPR) (1:64). CONCLUSION: According to epidemiological history, clinical presentation, non-treponemal tests, treponemal tests, and effective benzathine penicillin G treatment, confirmed secondary syphilis.