Traditional versus reverse syphilis algorithms: A comparison at a large academic medical center

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.

Screening and diagnostic testing protocols for HIV and Syphilis infections in health care setting in Qatar: Evaluation and recommendations

BACKGROUND

HIV and Syphilis are common STIs, which have become a concern and burden on healthcare systems, as many infections go untreated and lead to potentially serious complications. HIV is usually diagnosed with Western blot, PCR, and p24 antigen testing. Whereas, Syphilis is mainly diagnosed through clinical findings and serologic testing. The Medical Commission Department (MC) under MOPH is responsible for screening all newcomers to Qatar, aiming to keep the country free from serious infectious diseases.

OBJECTIVE

We aimed to evaluate the diagnostic efficiency of the protocols used in the MC for screening HIV and Syphilis infections.

METHODS

We conducted a retrospective study of samples analyzed by 4th Generation ARCHITECT® HIV Ag/Ab Combo and Rapid Plasma Reagin (RPR) between January to December 2019. ARCHITECT® HIV Ag/Ab Combo positive samples were confirmed by INNO-LIA™ HIVI/II and RT-PCR. RPR-reactive samples were confirmed by ARCHITECT® Syphilis Treponema pallidium Antibody (Syphilis TPA) assay.

RESULTS

For HIV, data were collected from 585,587 individuals, of which 595 (0.1%) were positive by the ARCHITECT® HIV Ag/Ab Combo (Analyzer A). When all initially positive sera were re-tested on newly collected blood samples using different ARCHITECT® HIV Ag/Ab Combo analyzer (analyzer B), 99.8% (594/595) of samples were also positive, suggesting high reproducibility. The positive predictive value (PPV) between ARCHITECT® HIV Ag/Ab Combo and the INNO-LIA™ HIVI/II confirmatory assay was 31.8%. The PPV between ARCHITECT® HIV Ag/Ab Combo and HIV-PCR assay was 26.8%. Retrospective data for Syphilis were collected from a total of 97,298 individuals who visited the MC, of which 198 (0.20%) were initially positive by RPR. The PPV between RPR and Syphilis TPA confirmatory assay was 36.6%.

CONCLUSION

Despite the high rate of false positivity using ARCHITECT® HIV Ag/Ab Combo and RPR screening assays, both assays have proven to be highly effective as screening testing methods.

Comparison of syphilis seropositivity between non-immigrant and immigrant populations in the Anatolian side of Istanbul, Turkiye: Results of five-years retrospective study

OBJECTIVE

Our study aimed to evaluate the seropositivity for syphilis in non- immigrant and immigrant populations and compare the results regarding demographic data.

METHODS

In accordance with the reverse algorithm, syphilis tests were performed between May 2014 and December 2018 in hospitals in our service zone for syphilis screening or symptomatic disease.

RESULTS

A total of 135.328 non- immigrant and 6.641 immigrant were screened for syphilis. Seropositivity rates were 1.3% in the non- immigrant and 3.8% in immigrant groups (p=0.0001). There was a statistically significant difference in terms of seropositivity rates between the various age groups in the local group and immigrant groups (except 18 25 age group) (p<0.05). Syphilis seropositivity rates were found to be lower in indigenous population than immigrant groups according to the years tested (p=0.0001). The seropositivity rates were 2.4% and 3.2% among the males (p=0.025) and 0.6% and 4.0% among females (p=0.0001) in non-immigrantand immigrant groups, respectively. Whereas, 0.6% of pregnant women in the local group and 3.7% of pregnant women in immigrant groups were seropositive for syphilis (p=0.0001). Among the HIV positive group, syphilis seropositivity was only observed in the non-immigrant group with a rate of 23.0% (p=0.0001).

CONCLUSION

The antibodies against syphilis were found more frequently in immigrants than non-immigrant. Among the HIV positive individuals syphilis seropositivity was only observed in the non-immigrant group.

Clinical Protocols and Treatment Guidelines for the Management of Maternal and Congenital Syphilis in Brazil and Portugal: Analysis and Comparisons: A Narrative Review

(1) Background: Maternal syphilis (MS) and congenital syphilis (CS) are serious public health problems worldwide due to their high morbidity and mortality rates. (2) Objective: Evaluating the applicability of Clinical Protocols and Treatment Guidelines on case incidence trends in Brazil and Portugal. (3) Methods: The review was done through bibliographic research in two public databases and government websites from both countries, published between 2007 and 2022. All guidelines that contained CS and MS were selected. (4) Results and discussion: After evaluation, we found that Brazil and Portugal have adequate protocols for screening and treating congenital and maternal syphilis. (5) Conclusion: The results suggest that CS and MS incidence are notably higher in Brazil than in Portugal due to economic, cultural, and social disparities and the differences in territory size. Therefore, these demographic and socioeconomic factors could strongly influence efforts to fight against syphilis and thus control the infection.

Risk Factors for Syphilis at a Large Urban Emergency Department

BACKGROUND

The prevalence of syphilis is increasing in the United States. The emergency department (ED) is an important setting to screen and treat underserved populations. To tailor testing protocols to the local population, we aimed to identify risk factors for syphilis positivity in ED patients.

METHODS

We performed a retrospective analysis of ED patients who were screened for syphilis between November 2018 and August 2020. Patients were screened for Treponema pallidum antibody using a multiplex flow immunoassay, and positive results were confirmed by rapid plasma reagin or T. pallidum particle agglutination. Risk factors for new syphilis diagnoses were identified using multiple logistic regression.

RESULTS

We screened 1974 patients for syphilis (mean age, 37 ± 16 years; 56% female). We identified 201 patients with new infections without previous treatment. Independent risk factors for a new diagnosis of syphilis included housing status (undomiciled, 23% [60 of 256]; domiciled, 9% [133 of 1559]; adjusted odds ratio [aOR], 1.9 [95% confidence interval {CI}, 1.2-3.0]), history of HIV (positive, 44% [28 of 63]; negative, 9% [173 of 1893]; aOR, 5.8 [95% CI, 3.0-11.2]), tobacco use (positive, 15% [117 of 797]; negative, 4% [29 of 665]; aOR, 2.4 [95% CI, 1.5-3.9]), and illicit drug use (positive, 14% [112 of 812]; negative, 8% [52 of 678]; aOR, 2.2 [95% CI, 1.0-2.5]).

CONCLUSIONS

Undomiciled housing status, history of HIV, history of tobacco use, and history of illicit drug use were independently associated with a new diagnosis of syphilis in the ED. Broadening targeted syphilis screening algorithms beyond sexually transmitted disease-related complaints could help identify new syphilis cases for treatment.

ED syphilis and gonorrhea/chlamydia cotesting practices before and after the implementation of an electronic health record-based alert

BACKGROUND

The prevalence of syphilis is increasing in many countries, including the USA. The ED is often used by underserved populations, making it an important setting to test and treat patients who are not evaluated in outpatient clinical settings. We aimed to assess the utility of an ED-based syphilis and gonorrhoea/chlamydia cotesting protocol by comparing testing practices before and after its implementation.

METHODS

We implemented an electronic health record (EHR) alert that prompted clinicians to order syphilis testing in patients undergoing gonorrhoea/chlamydia testing. We performed a retrospective cohort analysis that compared outcomes between the preimplementation period (January-November 2018) and the postimplementation period (January-November 2019). Patients were tested for Treponema pallidum antibody (TPA) using a multiplex flow immunoassay (MFI), and positive results were confirmed by rapid plasma reagin (RPR). The primary implementation outcome was the number of syphilis tests/month, and the primary clinical outcome was the number of syphilis diagnoses/month (defined as positive TPA MFI and RPR). We performed an interrupted time-series analysis to evaluate the effect of implementing the alert over time.

RESULTS

Four-hundred and ninety-four and 1106 unique patients were tested for syphilis in the preimplementation and postimplementation periods, respectively. Syphilis testing increased by 55.6 tests/month (95% CI 45.9 to 65.3, p<0.001) following alert implementation. Patients tested in the postimplementation period who were tested using the alert were much younger (difference: 14 years (95% CI 12 to 15)) and were more likely to be female (difference: 15% (95% CI 8 to 21)) and African-American (difference: 11% (95% CI 5 to 17)) than patients tested by clinician-initiated testing. Presumptive syphilis diagnoses increased from 3.4 diagnoses/month to 7.9 diagnoses/month (difference, 4.5 (95% CI 2.2 to 6.9), p<0.001).

CONCLUSIONS

Our study demonstrates that use of a targeted EHR alert testing protocol can increase syphilis testing and diagnosis and may reduce clinician bias in testing.

Syphilis diagnosis and serological response to Benzathine Penicillin G among patients attending HIV clinics in N'Djaména, Chad

BACKGROUND

Syphilis is endemic in the Sub-Saharan zone and disproportionately affects at-risk populations such as men who have sex with men, sex workers and HIV infected individuals. In this study, we measure the impact of syphilis among people living with HIV in the Republic of Chad, where no data are currently available.

METHOD

Outpatients attending 2 HIV clinics in N'Djamena, Republic of Chad, were tested for syphilis. Subjects who tested positive for both non-treponemal (VDRL) and treponemal (TPHA) received a single dose of Benzathine Penicillin G, 2.4 MU. An additional VDRL test was performed 6 months after treatment to ensure appropriate serological response.

RESULTS

Of 207 patients included, 29 (14%) tested positive for VDRL at the first visit, with moderate/low antibody titers (ranging from 1/2 to 1/8); 24 (82.6%) of these had treponemal immunization confirmed by TPHA test. Six months after Benzathine Penicillin treatment, 22/24 of the patients (91.6%) tested negative for VDRL, and 2 showed a 4-fold titer decline.

CONCLUSION

This first study in the Republic of Chad suggests that syphilis infection is frequent among people living with HIV in this country. Systematic screening of syphilis should be considered in this population.

Recognizing and limiting syphilis to prevent congenital syphilis

Syphilis is on the rise in every age and ethnicity group across the United States. The rate of congenital syphilis has started to rise as well, increasing the need for syphilis screening before pregnancy occurs. Raising awareness for syphilis screening, especially among sexually active women, is important, as the implications of this disease have lifelong effects for mother and child.

Laboratory Perspective on Racial Disparities in Sexually Transmitted Infections

BACKGROUND

Rates of sexually transmitted infections (STI) have risen steadily in recent years, and racial and ethnic minorities have borne the disproportionate burden of STI increases in the United States. Historical inequities and social determinants of health are significant contributors to observed disparities and affect access to diagnostic testing for STI.

CONTENT

Public health systems rely heavily on laboratory medicine professionals for diagnosis and reporting of STI. Therefore, it is imperative that clinicians and laboratory professionals be familiar with issues underlying disparities in STI incidence and barriers to reliable diagnostic testing. In this mini-review, we will summarize contributors to racial/ethnic disparity in STI, highlight current epidemiologic trends for gonorrhea, chlamydia, and syphilis, discuss policy issues that affect laboratory and public health funding, and identify specific analytic challenges for diagnostic laboratories.

SUMMARY

Racial and ethnic disparities in STI in the US are striking and are due to complex interactions of myriad social determinants of health. Budgetary cuts for laboratory and public health services and competition for resources during the COVID-19 pandemic are major challenges. Laboratory professionals must be aware of these underlying issues and work to maximize efforts to ensure equitable access to diagnostic STI testing for all persons, particularly those most disproportionately burdened by STI.

Standardised protocol for a prospective cross-sectional multicentre clinic-based evaluation of two dual point-of-care tests for the screening of HIV and syphilis in men who have sex with men, sex workers and pregnant women

INTRODUCTION

Dual point-of-care tests (POCTs) for detecting antibodies to HIV and syphilis have been developed for use with venous whole blood, serum/plasma or finger-prick capillary whole blood. Several tests are commercially available showing encouraging performance compared with 'gold-standard' reference tests in laboratory-based studies. However, data on their performance in the field are limited. This prospective cross-sectional study will conduct a clinic-based evaluation to assess the performance characteristics and acceptability to end-users of two dual HIV/syphilis POCTs for the screening of HIV and syphilis among men who have sex with men (MSM), sex workers (SWs) and pregnant women (PW). This master protocol outlines the overall research approach that will be used in seven countries.

METHOD AND ANALYSIS

MSM, SWs and PW presenting at clinic evaluation sites in high, low and middle-income countries will be enrolled. The (WHO preapproved) POCTs to be evaluated are SD Bioline HIV/Syphilis Duo (Abbott) and Dual Path Platform HIV-Syphilis Assay (Chembio). Finger-prick blood will be collected to perform POCTs and compared with laboratory results (venepuncture blood). Procedures will be carried out by trained healthcare staff and tests performed according to the manufacturers' directions. Sample size was calculated based on local prevalence of HIV and syphilis. The sensitivity, specificity, positive and negative predictive values for each POCT will be calculated. The study is ongoing with recruitment expected to be completed in all countries by mid to late 2021.

ETHICS AND DISSEMINATION

This core protocol was independently peer reviewed and approved by the Research Project Review Panel (RP2) of the WHO Department of Sexual and Reproductive Health and Research and by the WHO Ethics Review Committee (ERC). The protocol has been adapted to individual countries and approved by RP2, ERC and institutional review boards at each site. Results will be disseminated through peer-reviewed journals and relevant conferences.

Performance of Treponema pallidum recombinant proteins in the serological diagnosis of syphilis

Syphilis serodiagnosis is challenging because distinct clinical forms of the infection may influence serological performance and discordant results between tests make clinical decisions difficult. Several recombinant Treponema pallidum-proteins have already been tested for syphilis diagnosis and they are critical to achieve high accuracy in serological testing. Our aim was to assess the varied from performance of T. pallidum-recombinant proteins TmpA, TpN17 and TpN47 for syphilis serodiagnosis. The proteins were evaluated using sera of 338 T. pallidum-negative, 173 T. pallidum-positive individuals and 209 sera from individuals infected with unrelated diseases. The diagnostic potential was validated by analysis of ROC curves. In the liquid microarray analyses, the ROC curve varied from 99.0% for TmpA and TpN17 to 100% for TpN47. The sensitivity score yielded values of up to 90% for TpN17, 100% for TpN47 and 80.0% for TmpA. The lowest and highest specificity values were presented by TpN47 (91.9%) and TmpA antigens (100%), respectively. TpN47 showed the highest accuracy score (95.5%) among all the recombinant proteins assayed. For the ELISA, the ROC curve was 97.2%, 91.8% and 81.6% for TpN17, TmpA and TpN47, respectively. TpN17 and TmpA yielded a sensitivity of 69.9%, while TpN47 obtained a value of 53.8%. Specificity was almost 100% for all three proteins. No cross-reaction was observed for TpN17 in the serum samples from non-bacterial infections. Regarding leptospirosis-positive samples, cross-reactivity score was varied from 8.6 to 34.6%. This is most probably due to conservation of the epitopes in these proteins across bacteria. The use of recombinant proteins in immunoassays for syphilis diagnosis was showed provide greater reliability to results of the treponemal assays. Despite the low sensitivity, the proteins showed high diagnostic capacity due to the AUC values found. However, an improvement in sensitivity could be achieved when antigenic mixtures are evaluated.

Evaluation of the fully automated AIX1000 rapid plasma reagin system compared to a manual plasma reagin testing method for the diagnosis of syphilis

The analytical performance of the FDA-cleared AIX1000 automated RPR testing platform was evaluated in comparison to manual RPR card testing. Eight hundred thirty-three patient serum samples were analyzed, 87 samples were positive by the AIX1000, 108 were positive by the manual test method; overall agreement between methods was 96.5% (κ = 0.83). Cases were further classified by clinical and laboratory-based confirmation of disease, to which reactivity rates were compared, yielding sensitivities of 96.4% and 100%, and specificities of 99.2% and 96.8% for the automated and manual RPR methods, respectively. The difference in specificity between methods was statistically significant (P < 0.001). Twenty-five of 29 samples with discordant results were reactive by manual testing (titers of 1:1 or 1:2); 21 of 25 patients with negative AIX100 results were identified to have histories of remote, treated syphilis. Overall, the AIX1000 platform demonstrated excellent agreement with the manual RPR method; discrepancies occurred with specimens at the threshold of reactivity.

Evaluation of 4 Algorithms to Identify Incident Syphilis Among HIV-Positive Men Who Have Sex With Men Engaged in Primary Care

We developed 4 algorithms for syphilis among HIV-positive men who have sex with men who engaged in primary care in 2016 to 2017. Clinician-based diagnosis from chart reviews was the gold standard. Sensitivities ranged from 74.2% to 93.9%. Specificities were greater than 99% with positive and negative predictive values of greater than 95%. Algorithms that incorporated treatment data performed best.

Syphilis in Pregnancy

Importance

Since 2013, the United States has seen a rise in cases of congenital syphilis, culminating in a relative increase of 153% from 2013 to 2017 and 918 reported cases in 2017. In all, 50% to 80% of pregnant women with syphilis experience an adverse pregnancy outcome including stillbirth or spontaneous abortion.

Objective

This article aims to review the current evidence and recommendations for management of syphilis in pregnancy.

Evidence Acquisition

Original research articles, review articles, and guidelines on syphilis were reviewed.

Results

In pregnancy, routine screening for syphilis is recommended on initiation of prenatal care. In high-risk populations, repeat testing is recommended in the early third trimester and at delivery. Penicillin remains the recommended treatment in pregnancy. After treatment, nontreponemal titers should be repeated at minimum during the early third trimester and at delivery to assess for serologic response. In high-risk populations, titers should be repeated monthly.

Conclusion and Relevance

Routine screening in pregnancy is essential for identification of syphilis infection and prevention of congenital syphilis. Subsequent adequate treatment with penicillin therapy more than 30 days before delivery and at the correct dosages depending on the stage of infection should be incorporated into clinical practice.

Enzyme-linked immunosorbent assay (ELISA) versus Venereal Disease Research Laboratory test (VDRL) and rapid plasma reagin test (RPR) for screening of syphilis in pregnant women

OBJECTIVE

To evaluate a treponemal enzyme-linked immunosorbent assay (ELISA) as an alternative screening test for syphilis in pregnant women.

METHODS

A cross-sectional study of diagnostic test accuracy was carried out in a large volume laboratory from a tertiary care center. A total of 416 serum samples, including 102 archived syphilis Treponema pallidum hemagglutination (TPHA)-positive samples and 314 samples from pregnant women, were used to determine the sensitivity and specificity of ELISA. All the samples were subjected to Venereal Disease Research Laboratory (VDRL), rapid plasma reagin (RPR), ELISA, and TPHA tests. Performance characteristics of VDRL, RPR, and ELISA were calculated with TPHA as a reference standard test.

RESULTS

VDRL and RPR exhibited higher false positivity of 10.5% and 9.6%, respectively, compared to 2.5% by ELISA. The sensitivity and specificity of ELISA were 98% and 97.5%, of VDRL were 71.6% and 89.5%, and of RPR were 73.5% and 90.5%, respectively. Moreover, ELISA had an excellent agreement (kappa=0.9) with TPHA compared to VDRL/RPR which had a moderate agreement (kappa=0.6) only.

CONCLUSION

ELISA has the potential to replace VDRL/RPR as a screening test for syphilis in centers that can perform ELISA, especially for antenatal screening.

Syphilis: A growing concern

Since a brief low in 1998, reported cases of syphilis have continued to grow in the US. As primary care providers, NPs are at the forefront of the battle to eliminate syphilis. This article reviews the stages of this infection, diagnosis nuances, and treatment guidelines.

Endogenous endophthalmitis and other ocular manifestations of injection drug use

PURPOSE OF REVIEW

The United States has experienced a dramatic rise in opioid and injection drug use over the past 2 decades. A public health emergency was declared in 2017 and subsequently, there have been several new reports on the rise of endogenous endophthalmitis specifically associated with injection drug use. The purpose of this review is to provide a current perspective of the ocular harms posed by injection drug use.

RECENT FINDINGS

The opioid epidemic has prompted several new studies from New England, one of the US regions most heavily affected, that examine the trends and characteristics of injection drug use-associated endogenous endophthalmitis. Patients may delay seeking care and may be infected with a variety of rare and atypical microbes, and as a result clinical appearance may vary widely. Injection drug use also leads to embolic phenomena such as talc retinopathy and septic emboli from endocarditis. HIV is highly associated with injection drug use and although HAART has drastically reduced the morbidity and mortality of HIV-associated infections, a variety of ocular disease may accompany an immunocompromised patient.

SUMMARY

Healthcare providers must remain vigilant in the recognition of injection drug use patients with vision loss and ocular inflammation to ensure prompt medical and/or surgical treatment.

Evaluation of a Multiplex Fully Automated Treponemal and Nontreponemal (Rapid Plasma Reagin) Assay

OBJECTIVES

In June 2017, Bio-Rad Laboratories received US Food and Drug Administration clearance for its BioPlex 2200 Syphilis Total & RPR (rapid plasma reagin) assay. It is the first fully automated treponemal/nontreponemal multiplex flow immunoassay, simultaneously detecting Treponema pallidum and reagin antibodies and an RPR titer. We compared the performance of the BioPlex Syphilis Total & RPR assay with the LIAISON Treponema Assay and the manual BD Macro-Vue RPR 18-mm Circle Test.

METHODS

In total, 314 serum specimens were tested for treponemal immunoglobulin G/immunoglobulin M and RPR with the LIAISON Treponema Assay, the BioPlex 2200 Syphilis Total & RPR assay, and the manual BD Macro-Vue RPR card test. All discordant results were further tested with the T pallidum particle agglutination assay from Fujirebio Diagnostics.

RESULTS

The overall percent agreement for the BioPlex assay for treponemal antibodies with the LIAISON Treponema Assay was 96.1%. Sensitivity and specificity for the BioPlex RPR assay were 90.5% and 97.2%, respectively (the manual RPR assay was considered the gold standard).

CONCLUSIONS

The BioPlex 2200 Syphilis Total & RPR assay performance was comparable to the LIAISON Treponema Assay and the manual RPR test. Compared with the manual RPR, the automation of RPR testing offered labor savings, objective result reporting, and improved workflow.

Current ophthalmology practice patterns for syphilitic uveitis

Background

Syphilitic uveitis is re-emerging alongside the systemic infection. In July 2017, an international group of uveitis-specialised ophthalmologists formed the International Ocular Syphilis Study Group to define current practice patterns.

Methods

103 Study Group members based in 35 countries completed a 25-item questionnaire focused on case load, clinical presentations, use and interpretation of investigations, treatment and clinical indicators of poor prognosis.

Results

Members managed a mean of 6.1 patients with syphilitic uveitis in clinics that averaged 707 annual cases of uveitis (0.9%); 53.2% reported increasing numbers over the past decade. Patients presented to more members (40.2%) during secondary syphilis. Uveitis was usually posterior (60.8%) or pan (22.5%); complications included optic neuropathy, macular oedema and posterior synechiae. All members diagnosed syphilitic uveitis using serological tests (simultaneous or sequential testing algorithms), and 97.0% routinely checked for HIV co-infection. Cerebrospinal fluid (CSF) analysis was ordered by 90.2% of members, and 92.7% took uveitis plus Venereal Disease Research Laboratory test (VDRL) or fluorescent treponemal antibody absorption test (FTA-ABS) to indicate neurosyphilis. Patients were commonly co-managed with infectious disease physicians, and treated with penicillin for at least 10–14 days, plus corticosteroid. Features predicting poor outcome included optic neuropathy (86.3%) and initial misdiagnosis (63.7%). Reasons for delayed diagnosis were often practitioner-related. 82.5% of members tested every patient they managed with uveitis for syphilis.

Conclusion

This comprehensive report by an international group of uveitis-specialised ophthalmologists provides a current approach for the management of syphilitic uveitis.

Evaluation of the Elecsys Syphilis electrochemiluminescence immunoassay as a first-line screening test in the reverse algorithms for syphilis serodiagnosis

OBJECTIVES

With the development of the automated treponemal test, new syphilis serodiagnosis algorithms, reverse algorithm, and European Centre for Disease Prevention and Control (ECDC) algorithm have been recommended recently. We investigated the efficacy of an electrochemiluminescence immunoassay (ECLIA) as an initial screening test in the reverse and ECDC algorithms.

METHODS

Samples from 4,771 subjects were included in this study. We performed rapid plasma reagin (RPR), ECLIA, and Treponema pallidum particle agglutination (TPPA) according to these three algorithms. The fluorescent treponemal antibody absorbed (FTA-ABS) test was additionally applied for discordant cases between the RPR and ECLIA results. The FTA-ABS results and the consensus of three algorithms were considered a gold standard.

RESULTS

A total of 208 subjects were diagnosed with syphilis. The traditional algorithm had a sensitivity of 25.96%, specificity of 100%, and accuracy of 96.77%. Both the reverse and ECDC algorithms showed the same diagnostic performance, sensitivity of 95.19%, specificity of 99.96%, and accuracy of 99.75%. The agreements between the traditional algorithm and the other algorithms were 96.9% with a kappa value of 0.415.

CONCLUSIONS

The diagnostic accuracy of the reverse and ECDC algorithms using the ECLIA as a first-line screening test was superior to that of the traditional algorithm.

Clinical Performance of the BioPlex 2200 Syphilis Total & RPR Assay at a Tertiary Medical Center with a High Rate of Syphilis

Manual treponemal and nontreponemal serologic testing has historically been used for the diagnosis of syphilis. This approach is simple and reproducible but labor intensive. Recently, the FDA cleared the fully automated BioPlex 2200 Syphilis Total & RPR assay for the detection of treponemal and nontreponemal antibodies. We evaluated the clinical performance of this assay at a tertiary medical center with a high syphilis prevalence. Prospective consecutively collected (n = 400) and known RPR-positive (n = 100) specimens were compared using predicate manual rapid plasma reagin (RPR) and fluorescent treponemal antibody absorption (FTA) methods and the BioPlex 2200 Syphilis Total & RPR assay. Positive and negative percent agreements (PPA and NPA, respectively) between the assays were calculated. The PPA and NPA between the manual and BioPlex 2200 RPR results for the prospective population were 85% (17/20; 95% confidence interval [CI], 69% to 100%) and 98% (373/380; 95% CI, 97% to 99%), respectively. The PPA for the manual RPR-positive population was 88% (88/100; 95% CI, 82% to 94%). Overall, the manual and BioPlex 2200 RPR titers demonstrated 78% (99/127) concordance within ±1 dilution and 94% (120/127) within ±2 dilutions. An interpretation of the syphilis serologic profile using the traditional algorithm showed a concordance of 99.5% in the prospective population and 85% in the manual RPR-positive cohort. The performance of the BioPlex 2200 Syphilis Total & RPR assay is comparable to those of manual methods. The high NPA of this assay combined with the ability to automate a historically labor-intensive assay is an appealing attribute for syphilis screening in a high-volume laboratory.

Limited efficacy of nontreponemal test combined with treponemal test in the initial syphilis screening algorithm

PURPOSE

Various syphilis screening algorithms have been proposed and are now used by many clinical laboratories following the introduction of automated treponemal tests (TTs). In France, the diagnosis of syphilis is based on a TT combined with a nontreponemal test (NTT). The objective of this study was to evaluate the diagnostic impact of NTT on initial syphilis screening at the Amiens University Hospital between January 2013 and December 2016.

METHODOLOGY

Serum samples sent for syphilis testing were analysed using a treponemal enzyme immunoassay (Siemens IMMULITE 2000 Syphilis Screen) combined with a nontreponemal test. Enzyme immunoassay (EIA)-reactive and/or nontreponemal-reactive samples were titrated to endpoint using the Treponema pallidum particle agglutination test (TPHA). Complementary tests, such as line immunoassay, and medical charts were reviewed to categorize reactive samples into positive or negative syphilis contacts.

RESULTS

Among 15 523 initial screening samples, 148 samples (0.95 %) were reactive with the combined TT and NTT, and 335 (2.16 %) and 66 (0.42 %) were reactive with TT or NTT only. Analysis of the 66 discordant results between TT and NTT showed that only 4 sera were reactive with a second-line TPHA, but these results were not confirmed by line immunoassay and patient characteristics.

CONCLUSION

The results of this study show that the combination of NTT and TT for initial screening does not provide any diagnostic gain, but represents additional laboratory work time.

Immunochip for Syphilis Serodiagnostics with the Use of Extended Array of Treponema pallidum Recombinant Antigens

An immunochip for multiple parallel detection of specific serum IgG in serological screening for syphilis is based on the use of an extended array of Treponema pallidum recombinant proteins and includes traditionally used immunodominant antigens (Tp15, Tp17, Tp47, and TmpA) and new synthetic proteins (Tp0277, Tp0319, Tp0453, Tp0684, Tp0965, and Tp1038). The use of individual antigens has demonstrated high analytical value of Tp0277 (periplasmatic C-terminal protease), Tp0319 (cytoplasmic membrane-associated lipoprotein TmpC), and external membrane-associated protein Tp0453 with transporting function, all of them improving significantly the efficiency of screening for syphilis in comparison with the traditional array of antigens. Multiparametric analysis of the results obtained on the immunochip with the use of linear discriminant analysis confirmed the efficiency of extended array of T. pallidum diagnostic antigens. Due to proposed modification, the "positive" and "negative" sera are clearly differentiated: the serological study showed 94.1% sensitivity and 100% specificity.

Using Focused Laboratory Management and Quality Improvement Projects to Enhance Resident Training and Foster Scholarship

Training in patient safety, quality, and management is widely recognized as an important element of graduate medical education. These concepts have been intertwined in pathology graduate medical education for many years, although training programs face challenges in creating explicit learning opportunities in these fields. Tangibly involving pathology residents in management and quality improvement projects has the potential to teach and reinforce key concepts and further fulfill Accreditation Council for Graduate Medical Education goals for pursuing projects related to patient safety and quality improvement. In this report, we present our experience at a pathology residency program (University of Iowa) in engaging pathology residents in projects related to practical issues of laboratory management, process improvement, and informatics. In this program, at least 1 management/quality improvement project, typically performed during a clinical chemistry/management rotation, was required and ideally resulted in a journal publication. The residency program also initiated a monthly management/informatics series for pathology externs, residents, and fellows that covers a wide range of topics. Since 2010, all pathology residents at the University of Iowa have completed at least 1 management/quality improvement project. Many of the projects involved aspects of laboratory test utilization, with some projects focused on other areas such as human resources, informatics, or process improvement. Since 2012, 31 peer-reviewed journal articles involving effort from 26 residents have been published. Multiple projects resulted in changes in ongoing practice, particularly within the hospital electronic health record. Focused management/quality improvement projects involving pathology residents can result in both meaningful quality improvement and scholarly output.