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.

A Position Statement on Mpox as a Sexually Transmitted Disease.

The global outbreak of mpox virus constituted an international public health emergency. Reports have highlighted (1) a temporal association between sexual activity and mpox, (2) an association between specific sexual practices and location of lesion development, (3) a high frequency of sexual practices conferring risk for other sexually transmitted infections among cases of mpox, (4) that mpox virus can be isolated from sexual fluids, (4) that isolated virus is infectious, and (5) a high frequency of anogenital lesions prior to disease dissemination suggesting direct inoculation during sexual activities. Finally, a growing body of evidence suggests that sexual transmission is the predominant mode of transmission for mpox virus. We therefore conclude that mpox is a sexually transmitted disease. Labeling it as such will help focus public health interventions, such as vaccinations, testing, and treatment, as well as facilitate focused awareness and education programs toward behavioral modifications to reduce exposures.

HPV type-specific trends in cervical precancers in the United States, 2008 to 2016.

Declines in cervical intraepithelial neoplasia grades 2 to 3 and adenocarcinoma in situ (CIN2+) observed among young women suggest impact from human papillomavirus (HPV) vaccination. To further evaluate vaccine impact including cross-protection and type replacement, we described high-risk (HR)-HPV type-specific cervical precancer incidence rates among women aged 20 to 39 years, 2008 to 2016. We analyzed cross-sectional population-based data on 18 344 cases of CIN2+ from a 5-site surveillance system. Diagnostic specimens were tested for individual HPV types, including 14 HR-HPV types (HPV16/18/31/33/35/39/45/51/52/56/58/59/66/68). We estimated age-specific annual HR-HPV type-specific CIN2+ incidence per 100 000 screened women for individual types, vaccine HR-HPV types (HPV16/18) and nonvaccine HR-HPV types (non-HPV16/18). We evaluated trends using average annual percent changes (AAPC) and 95% confidence intervals (CI), and estimated total declines by comparing 2015-2016 to 2008-2009 using incidence rate ratios. Among 20-24-year-olds, HPV16/18-CIN2+ declined from 2008 through 2016 (AAPC: -21.3%, 95% CI: -28.1%, -13.8%), whereas no trend was observed for non-HPV16/18-CIN2+ (AAPC: -1.8%, 95% CI: -8.1%, 4.9%). After 2010, CIN2+ among 20-24-year-olds was more often caused by nonvaccine vs vaccine HR-HPV types. No significant declining trends were observed in older age groups. In 2015-2016 compared with 2008-2009, HPV16-CIN2+ declined 78%, HPV18-CIN2+ 72% and HPV31-CIN2+ 51% among 20-24-year-olds; no increases were observed in type-specific CIN2+ incidence. Among 25-29-year-olds, HPV16-CIN2+ declined 18%; CIN2+ attributed to seven nonvaccine types increased significantly. No significant declines were observed in older groups. Significant declines in HPV16/18-CIN2+ in 20-24-year-olds and HPV16-CIN2+ in 25-29-year-olds corroborate impact of HPV vaccination. A declining trend in HPV31-CIN2+ is consistent with cross-protection from vaccination.

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.

Sexually Transmitted Infection Screening in Key Populations of Persons Living with HIV.

Annual screening for bacterial sexually transmitted infections (STI), including gonorrhea/chlamydia (GC/CT) and syphilis, is recommended for persons with HIV (PWH). We used the prevention index to quantify the extent to which STI screening was completed at guideline-recommended frequency in African American and Latinx persons, women, persons with alcohol (AUD) and substance (SUD) use disorders. Data from PWH at Kaiser Permanente Northern California were collected from electronic health records. We defined receipt of GC/CT and syphilis screening consistent with recommendations as a prevention index score ≥ 75%. Among 9655 PWH (17.7% Latinx; 16.2% African American; 9.6% female; 12.4% AUD; 22.1% SUD), prevention index scores for GC/CT and syphilis increased from 2015 to 2019. African American PWH had lower odds of receiving an annual syphilis screen (aOR 0.87 [95% CI 0.79-0.97]). Female sex was associated with lower odds of GC/CT (aOR 0.30 [95% CI 0.27-0.34]) and syphilis (aOR 0.27 [95% CI 0.24-0.310) screening. AUD and SUD were not associated with differences in annual GC/CT or syphilis screening. Key PWH subgroups experience ongoing challenges to annual STI screening despite comparable healthcare access.

Investigating influencing factors on premenstrual syndrome (PMS) among female college students.

BACKGROUND: Premenstrual syndrome (PMS) affects women's physical and mental health. Depression, stress, sleep disturbance, and eating attitude problems have been known to influence PMS. Furthermore, restrictions of daily life due to the COVID-19 pandemic have led to changes in sleep patterns and eating attitudes. Thus, it is necessary to closely examine how these factors affect PMS. This study aimed to examine the levels of PMS, stress, depression, sleep disturbance, and eating attitude problems among female college students who experience dysmenorrhea and determine the factors associated with PMS. METHODS: A cross-sectional online survey design was conducted using a convenience sample of 143 female college students in C City, South Korea. Data were collected from September 1 to 19, 2021 in South Korea using an online self-administered survey. Differences in participants' level of PMS according to physical health variables (e.g., smoking, water intake, menstrual pain intensity) and psychological issues (i.e., stress, depression, sleep disturbances, and eating attitude problems) were assessed with independent sample t-tests and one-way ANOVAs. Correlational analyses between these variables were also conducted. Additionally, multiple regression was performed to identify the factors influencing PMS. RESULTS: PMS severity was between normal (27.3%) and premenstrual dysphoric disorder (PMDD) (72.7%). PMS was associated positively with depression (r = .284, p = 001), stress (r = .274, p = .001), sleep disturbance (r = .440, p < .001), and eating attitude problems (r = .266, p = .001). Additionally, menstrual pain intensity (ß = 0.204), sleep disturbances (ß = 0.375), and eating attitude problems (ß = 0.202) were found to influence PMS. The regression model was significant (F = 16.553, p < .001) with an explanatory power of 24.7%. CONCLUSIONS: Considering the influencing factors of PMS identified in this study, interventions for participants experiencing PMS should be made. We propose that further study should be conducted to examine whether the severity of PMS changes according to menstrual pain, the pattern and degree of its change, and the paths through which sleep quality and eating attitude problems affect PMS.

Chemical Vapor Deposition of Edge-on Oriented 2D Conductive Metal-Organic Framework Thin Films.

We demonstrated the synthesis of a conductive two-dimensional metal-organic framework (MOF) thin film by single-step all-vapor-phase chemical vapor deposition (CVD). The synthesized large-area thin film of Cu3(C6O6)2 has an edge-on-orientation with high crystallinity. Cu3(C6O6)2 thin film-based microdevices were fabricated by e-beam lithography and had an electrical conductivity of 92.95 S/cm. Synthesis of conductive MOF thin films by the all-vapor-phase CVD will enable fundamental studies of physical properties and may help to accomplish practical applications of conductive MOFs.

Sexually Transmitted Infections Treatment Guidelines, 2021.

These guidelines for the treatment of persons who have or are at risk for sexually transmitted infections (STIs) were updated by CDC after consultation with professionals knowledgeable in the field of STIs who met in Atlanta, Georgia, June 11-14, 2019. The information in this report updates the 2015 guidelines. These guidelines discuss 1) updated recommendations for treatment of Neisseria gonorrhoeae, Chlamydia trachomatis, and Trichomonas vaginalis; 2) addition of metronidazole to the recommended treatment regimen for pelvic inflammatory disease; 3) alternative treatment options for bacterial vaginosis; 4) management of Mycoplasma genitalium; 5) human papillomavirus vaccine recommendations and counseling messages; 6) expanded risk factors for syphilis testing among pregnant women; 7) one-time testing for hepatitis C infection; 8) evaluation of men who have sex with men after sexual assault; and 9) two-step testing for serologic diagnosis of genital herpes simplex virus. Physicians and other health care providers can use these guidelines to assist in prevention and treatment of STIs.

Characteristics of the Audience Reached by the National Network of Sexually Transmitted Disease Clinical Prevention Training Centers and Correlation With Sexually Transmitted Infection Rates, 2015 to 2020.

BACKGROUND: The National Network of Sexually Transmitted Disease Clinical Prevention Training Centers (NNPTC) trains clinical providers to diagnose and treat sexually transmitted infections (STIs) in the United States. The purpose of this study was to examine the demographics of clinical providers and to correlate the number of training episodes with STI rates at the county level. METHODS: Registration data were collected between April 1, 2015, and March 31, 2020, in a custom Learning Management System from clinical providers taking NNPTC training. Using the 2018 STI surveillance data, counties were divided into quartiles based on reportable STI case rates and the number of county-level training events was compared per quartile. Univariate and multivariate analyses were conducted in IBM SPSS Statistics 23 (Armonk, NY) and SAS Enterprise Guide 7.1 (Cary, NC). RESULTS: From 2015 to 2020, the NNPTC trained 21,327 individuals, predominantly in the nursing professions and working in a public health environment. In multivariate analysis, the number of training events was significantly associated with higher STI rates at the county level (P < 0.0001) and the state where a prevention training center is located (P < 0001). CONCLUSIONS: The analysis suggests that NNPTC trainings are reaching the clinical providers working in geographic areas with higher STI rates.

Extraordinary Photostability and Davydov Splitting in BN-Sandwiched Single-Layer Tetracene Molecular Crystals.

Two-dimensional molecular crystals have been beyond the reach of systematic investigation because of the lack or instability of their well-defined forms. Here, we demonstrate drastically enhanced photostability and Davydov splitting in single and few-layer tetracene (Tc) crystals sandwiched between inorganic 2D crystals of graphene or hexagonal BN. Molecular orientation and long-range order mapped with polarized wide-field photoluminescence imaging and optical second-harmonic generation revealed high crystallinity of the 2D Tc and its distinctive orientational registry with the 2D inorganic crystals, which were also verified with first-principles calculations. The reduced dielectric screening in 2D space was manifested by enlarged Davydov splitting and attenuated vibronic sidebands in the excitonic absorption and emission of monolayer Tc crystals. Photostable 2D molecular crystals and their size effects will lead to novel photophysical principles and photonic applications.

At-Home Specimen Self-Collection and Self-Testing for Sexually Transmitted Infection Screening Demand Accelerated by the COVID-19 Pandemic: a Review of Laboratory Implementation Issues.

The coronavirus disease 2019 (COVID-19) pandemic reduced the sexually transmitted infection (STI) testing volume due to social-distancing and stay-at-home orders, among other reasons. These events highlighted previously known benefits of at-home STI self-testing or specimen self-collection and accelerated testing demand via telemedicine. We review testing outside traditional clinical settings. We focus on three curable bacterial STIs among the top 10 U.S. nationally notifiable conditions with screening recommendations: syphilis, gonorrhea (Neisseria gonorrhoeae, also known as the gonococcus [GC]), and chlamydia (Chlamydia trachomatis). At least 19 million GC/C. trachomatis (GC/CT) screening or diagnostic tests are performed annually, presenting a considerable challenge during the pandemic. Unlike for HIV, STI at-home tests are currently not commercially available. However, innovative telemedicine providers currently offer services where specimen self-collection kits are mailed to patients at home who then ship them to laboratories for processing. We discuss technical and regulatory aspects of modifications for home-based specimen self-collection. The telemedicine provider typically manages and communicates results, provides linkage to care, and is responsible for billing and case reporting. We also describe rapid testing devices in development that may present an opportunity for future self-testing. In summary, COVID-19 has accelerated the evaluation and development of STI self-tests and specimen self-collection. The remaining obstacles are high price, regulatory approval, support for laboratories offering the service, and uncertainty regarding whether target populations with the greatest need are reached effectively. However, increased testing, convenience, and privacy are potential benefits that may enhance uptake and outlast the pandemic.

Knowing What We Do Not Know: Analysis of an Online Consultation Service to Identify Provider Knowledge Gaps in Sexually Transmitted Disease Care.

The national Sexually Transmitted Diseases (STD) Clinical Consultation Network receives requests regarding complex STD cases. A total of 927 requests from Western states, 2017 to 2019, were analyzed for STD of inquiry and syphilis-specific subtopics. Syphilis requests accounted for most queries, and the number and proportion of syphilis-related requests increased significantly over time.

Congenital Syphilis: A Case Report Demonstrating Missed Opportunities for Screening and Inadequate Treatment Despite Multiple Health Care Encounters During Pregnancy.

ABSTRACT: A case of congenital syphilis due to multiple missed opportunities, highlights the challenges of treating syphilis during pregnancy. Although cases are increasing in the United States, congenital syphilis, a disease with devastating consequences, is preventable.

Improved Gonorrhea and Chlamydia Testing Among Men Who Have Sex With Men Living With HIV Through Implementation of Self-Collected Tests.

ABSTRACT: We implemented self-collected gonorrhea/chlamydia testing in 17 medical centers in California serving men who have sex with men living with HIV. From 2012 to 2018, gonorrhea/chlamydia testing increased from 45.2% to 63.4%. Among those tested, rectal testing increased from 42.0% to 77.3%; pharyngeal testing increased from 31.0% to 79.9% (all, Ptrend < 0.0001).

Increases in Human Papillomavirus Testing Preceding Diagnosis of Cervical Precancer in 5 US States, 2008-2016.

OBJECTIVE: The aim of the study was to describe trends in human papillomavirus (HPV) testing preceding diagnosis of cervical precancer during a time of changing screening recommendations. MATERIALS AND METHODS: We conducted a cross-sectional analysis of data from active, population-based, laboratory surveillance among 1.5 million residents of 5 areas in the United States. We included women aged 21-39 years diagnosed with cervical intraepithelial neoplasia grades 2, 2/3, or 3 or adenocarcinoma in situ (collectively, CIN2+) during 2008-2016, who had a cytology and/or HPV test before diagnosis (n = 16,359). RESULTS: The proportion of women with an HPV test preceding CIN2+ increased from 42.9% in 2008 to 73.3% in 2016 (p < .01); testing increased in all age groups (21-24 y: 35.3% to 47.6%, 25-29 y: 40.9% to 64.1%, 30-39 y: 51.7% to 85.9%, all p < .01). The HPV testing varied by cytology result and was highest among women with atypical squamous cells of unknown significance (n = 4,310/4,629, 93.1%), negative for intraepithelial lesion or malignancy (n = 446/517, 86.3%), and atypical glandular cells (n = 145/257, 56.4%). By 2016, at least half of all cases in every surveillance area had an HPV test before diagnosis. CONCLUSIONS: During 2008-2016, the proportion of women with an HPV test preceding CIN2+ increased significantly for all age groups, cytology results, and surveillance areas. By 2016, most (85.9%) women aged 30-39 years had an HPV test, consistent with recommendations. Increasing utilization of HPV tests, which have demonstrated improved sensitivity for detecting cervical disease, may in part explain increasing rates of cervical precancer among women 30 years and older.

Sensitivity and Specificity of Treponemal-specific Tests for the Diagnosis of Syphilis.

We conducted a systematic review of relevant syphilis diagnostic literature to address the question, "What is the sensitivity and specificity of the treponemal tests currently approved by the Food and Drug Administration (FDA) for the diagnosis of syphilis (by stage)?" There were 16 treponemal assays evaluated: 13 immunoassays and 3 manual assays (fluorescent treponemal antibody absorbed test [FTA-ABS], microhemagglutination assay for Treponema pallidum antibodies [MHA-TP], Treponema pallidum particle agglutination assay [TP-PA]). MHA-TP and FTA-ABS were less sensitive in primary and secondary syphilis than TP-PA; TP-PA is the most specific manual treponemal assay. There is insufficient evidence to recommend one particular treponemal immunoassay (eg, enzyme immunoassays, chemiluminescence immunoassays, microbead immunoassays) over another based on published performance data. For diagnosis of neurosyphilis, cerebrospinal fluid (CSF) TP-PA has similar performance to CSF FTA-ABS in studies with patients with definitive or presumptive neurosyphilis. However, CSF treponemal testing has limitations in its sensitivity and specificity and should be interpreted within the context of the clinical scenario, additional CSF test results and syphilis prevalence.

Cervical adenocarcinoma in situ: Human papillomavirus types and incidence trends in five states, 2008-2015.

Primary prevention through the use of human papillomavirus (HPV) vaccination is expected to impact both cervical intraepithelial neoplasia (CIN) and adenocarcinoma in situ (AIS). While CIN is well described, less is known about the epidemiology of AIS, a rare cervical precancer. We identified AIS and CIN grade 3 (CIN3) cases through population-based surveillance, and analyzed data on HPV types and incidence trends overall, and among women screened for cervical cancer. From 2008 to 2015, 470 AIS and 6,587 CIN3 cases were identified. The median age of women with AIS was older than those with CIN3 (35 vs. 31 years; p < 0.01). HPV16 was the most frequently detected type in both AIS and CIN3 (57% in AIS; 58% in CIN3), whereas HPV18 was the second most common type in AIS and less common in CIN3 (38% vs. 5%; p < 0.01). AIS lesions were more likely than CIN3 lesions to be positive for high-risk types targeted by the bivalent and quadrivalent vaccines (HPV16/18, 92% vs. 63%; p < 0.01), and 9-valent vaccine (HPV16/18/31/33/45/52/58, 95% vs. 87%; p < 0.01). AIS incidence rates decreased significantly in the 21-24 year age group (annual percent change [APC] overall: -22.1%, 95% CI: -33.9 to -8.2; APC among screened: -16.1%, 95% CI: -28.8 to -1.2), but did not decrease significantly in any older age group. This report on the largest number of genotyped AIS cases to date suggests an important opportunity for vaccine prevention of AIS, and is the first to document a decline in AIS incidence rates among young women during the vaccine era.

Effectiveness of 1, 2, and 3 Doses of Human Papillomavirus Vaccine Against High-Grade Cervical Lesions Positive for Human Papillomavirus 16 or 18.

Before 2016, human papillomavirus (HPV) vaccination was recommended on a 3-dose schedule. However, many vaccine-eligible US females received fewer than 3 doses, which provided an opportunity to evaluate the real-world vaccine effectiveness (VE) of 1, 2, and 3 doses. We analyzed data on cervical intraepithelial neoplasia (CIN) grades 2-3 and adenocarcinoma in situ (designated CIN2+) from the HPV Vaccine Impact Monitoring Project (HPV-IMPACT; 2008-2014). Archived tissue from CIN2+ lesions was tested for 37 types of HPV. Women were classified by number of doses received ≥24 months before CIN2+ detection. Using a test-negative design, VE was estimated as 1 minus the adjusted odds ratio from a logistic regression model that compared vaccination history for women whose lesions tested positive for HPV-16/18 (vaccine-type cases) with that for women who had all other CIN2+ lesions (controls). Among 3,300 women with available data on CIN2+, typing results, and vaccine history, 1,561 (47%) were HPV-16/18-positive, 136 (4%) received 1 dose of HPV vaccine, 108 (3%) received 2 doses, and 325 (10%) received 3 doses. Adjusted odds ratios for vaccination with 1, 2, and 3 doses were 0.53 (95% confidence interval (CI): 0.37, 0.76; VE = 47%), 0.45 (95% CI: 0.30, 0.69; VE = 55%), and 0.26 (95% CI: 0.20, 0.35; VE = 74%), respectively. We found significant VE against vaccine-type CIN2+ after 3 doses of HPV vaccine and lower but significant VE with 1 or 2 doses.

Reversible Polymorphic Transition and Hysteresis-Driven Phase Selectivity in Single-Crystalline C8-BTBT Rods.

Organic semiconductors (OSCs) are highly susceptible to the formation of metastable polymorphs that are often transformed by external stimuli. However, thermally reversible transformations in OSCs with stability have not been achieved due to weak van der Waals forces, and poor phase homogeneity and crystallinity. Here, a polymorph of a single crystalline 2,7-dioctyl[1] benzothieno[3,2-b][1]benzothio-phene rod on a low molecular weight poly(methyl methacrylate) (≈120k) that limits crystal coarsening during solvent vapor annealing is fabricated. Molecules in the polymorph lie down slightly toward the substrate compared to the equilibrium state, inducing an order of greater resistivity. During thermal cycling, the polymorph exhibits a reversible change in resistivity by 5.5 orders with hysteresis; this transition is stable toward bias and thermal cycling. Remarkably, varying cycling temperatures leads to diverse resistivities near room temperature, important for nonvolatile multivalue memories. These trends persist in the carrier mobility and on/off ratio of the polymorph field-effect transistor. A combination of in situ grazing incident wide angle X-ray scattering analyses, visualization for electronic and structural analysis simulations, and density functional theory calculations reveals that molecular tilt governs the charge transport characteristics; the polymorph transforms as molecules tilt, and thereby, only a homogeneous single-crystalline phase appears at each temperature.

Performance of Treponemal Tests for the Diagnosis of Syphilis.

BACKGROUND: Treponemal immunoassays are increasingly used for syphilis screening with the reverse sequence algorithm. There are few data describing performance of treponemal immunoassays compared to traditional treponemal tests in patients with and without syphilis. METHODS: We calculated sensitivity and specificity of 7 treponemal assays: (1) ADVIA Centaur (chemiluminescence immunoassay [CIA]); (2) Bioplex 2200 (microbead immunoassay); (3) fluorescent treponemal antibody absorption test (FTA-ABS); (4) INNO-LIA (line immunoassay); (5) LIAISON CIA; (6) Treponema pallidum particle agglutination assay (TPPA); and (7) Trep-Sure (enzyme immunoassay [EIA]), using a reference standard combining clinical diagnosis and serology results. Sera were collected between May 2012-January 2013. Cases were characterized as: (1) current clinical diagnosis of syphilis: primary, secondary, early latent, late latent; (2) prior treated syphilis only; (3) no evidence of current syphilis, no prior history of syphilis, and at least 4 of 7 treponemal tests negative. RESULTS: Among 959 participants, 262 had current syphilis, 294 had prior syphilis, and 403 did not have syphilis. FTA-ABS was less sensitive for primary syphilis (78.2%) than the immunoassays or TPPA (94.5%-96.4%) (all P ≤ .01). All immunoassays were 100% sensitive for secondary syphilis, 95.2%-100% sensitive for early latent disease, and 86.8%-98.5% sensitive in late latent disease. TPPA had 100% specificity. CONCLUSIONS: Treponemal immunoassays demonstrated excellent sensitivity for secondary, early latent, and seropositive primary syphilis. Sensitivity of FTA-ABS in primary syphilis was poor. Given its high specificity and superior sensitivity, TPPA is preferred to adjudicate discordant results with the reverse sequence algorithm over the FTA-ABS.