Syphilis in Colorado - Provider Information

pregnant woman and dr

Provider resources

Syphilis rates are increasing in men, women and newborns. Knowing who and when to screen is critical. Taking a Sexual Health History is critical in helping to determine how often your patient should be screened for syphilis. 

  • Screen asymptomatic women at increased risk (history of incarceration or transactional sex work, geography, race/ethnicity) for syphilis infection
Pregnant People
  • All pregnant people at the first prenatal visit
  • Retest at 28 weeks gestation and at delivery if at high risk (lives in a community with high syphilis morbidity or is at risk for syphilis acquisition during pregnancy [drug misuse, STIs during pregnancy, multiple partners, a new partner, partner with STIs])
Men Who Have Sex With Women
  • Screen asymptomatic adults at increased risk (history of incarceration or transactional sex work, geography, race/ethnicity, and being a male younger than 29 years) for syphilis infection
Men Who Have Sex With Men
  • At least annually for sexually active MSM
  • Every 3 to 6 months if at increased risk
  • Screen asymptomatic adults at increased risk (history of incarceration or transactional sex work, geography, race/ethnicity, and being a male younger than 29 years) for syphilis infection
Transgender and Gender Diverse People
  • Consider screening at least annually based on reported sexual behaviors and exposure
Persons with HIV
  • For sexually active individuals, screen at first HIV evaluation, and at least annually thereafter
  • More frequent screening might be appropriate depending on individual risk behaviors and the local epidemiology


Serologic testing has been the standard for syphilis diagnosis. Serologic testing is divided into two major groups: treponemal, which tests for specific antibodies to Treponema pallidum (the causative organism), and nontreponemal, which tests for antibodies to a cardiolipin-cholesterol-lecithin antigen. 

Treponemal antibody tests include the fluorescent treponemal antibody absorption (FTA-ABS), Treponema pallidum particle agglutination assay (TP-PA), enzyme immunoassays (EIAs), and chemiluminescence immunoassays (CIAs). 

Non-treponemal tests include the rapid plasma reagin (RPR) test and the Venereal Disease Research Laboratory (VDRL) test. The RPR is performed on blood and the VDRL can be performed on blood or spinal fluid. 

The diagnosis of syphilis requires the use of both nontreponemal and treponemal tests; hence, there are two commonly used approaches for the serologic diagnosis of syphilis – traditional and ‘reverse’ algorithms
Traditional and Reverse Screening Algorithms


Traditional and Reverse Screening Algorithms

syphilis serology algo chart

  • False-positive nontreponemal test results can be associated with multiple medical conditions and factors unrelated to syphilis, including other infections (e.g., HIV), autoimmune conditions, vaccinations, injecting drug use, pregnancy, and older age. Therefore, persons with a reactive nontreponemal test should always receive a treponemal test to confirm the syphilis diagnosis (i.e., traditional algorithm). 


syphilis serology algo chart

  • The majority of patients who have reactive treponemal tests will have reactive tests for the remainder of their lives, regardless of adequate treatment or disease activity. 
  • Reverse sequence algorithm for syphilis testing can identify persons previously treated for syphilis, those with untreated or incompletely treated syphilis, and those with false-positive results that can occur with a low likelihood of infection. 
  • Persons with a positive treponemal screening test should have a standard quantitative nontreponemal test with titer performed reflexively by the laboratory to guide patient management decisions. If the nontreponemal test is negative, the laboratory should perform a treponemal test different from the one used for initial testing, preferably TP-PA or treponemal assay based on different antigens than the original test, to adjudicate the results of the initial test.

Syphilis can be separated into four different stages: primary, secondary, early non-primary/non-secondary, and unknown duration or late syphilis. Understanding the different stages for syphilis is crucial when it comes to managing syphilis. Symptoms often help us understand more about the duration of the infection, and the treatment needed. 

Want to learn more? Visit the links to learn more about staging and treating syphilis: 

Need help locating syphilis testing and/or treatment? Please visit our Syphilis Testing & Treatment Locator. If you would like to add or update your agency information, please complete this form.

Be aware of Neurosyphilis, Ocular syphilis, and Otosyphilis (this may occur at any stage!)

  • Screen for neurologic, visual, and cochleo-vestibular  symptoms and signs in patients at risk for syphilis or newly diagnosed with syphilis. 
  • Screen patients for syphilis if they present with neurologic, visual, or cochleo-vestibular complaints.
  • Conduct a careful neurological exam, including an evaluation of all cranial nerves, for patients with symptoms of neurologic, visual, or cochleo-vestibular dysfunction and reactive non treponemal and treponemal serology. 
  • Conduct an immediate ophthalmologic evaluation for patients with syphilis and ocular complaints.
  • Evaluate and manage patients with syphilis and cochleo-vestibular symptoms in collaboration with an otolaryngologist

Neurosyphilis is a result of invasion of the central nervous system by Treponema pallidum, which can occur at any stage of syphilis. It is unknown whether certain T. pallidum strains are neurotropic. Early neurologic clinical manifestations (e.g., cranial nerve dysfunction, meningitis, meningovascular syphilis, stroke, and altered mental status) are usually present within the first few months or years of infection. Late neurologic manifestations (e.g., tabes dorsalis and general paresis) occur 10–30 years after infection but can occur earlier in people who are immunocompromised.

Treatment for neurosyphilis should be managed according to the STI Treatment Guidelines, 2021 – Neurosyphilis, Ocular Syphilis, and Otosyphilis.

Ocular Syphilis
Ocular Syphilis can occur at any stage of syphilis, with variable clinical presentations, including isolated ocular abnormalities or with neurologic manifestations. Ocular syphilis can involve almost any eye structure, but posterior uveitis and panuveitis are the most common clinical manifestations. Additional ocular manifestations may include anterior uveitis, optic neuropathy, retinal vasculitis, and interstitial keratitis. Ocular syphilis may lead to decreased visual acuity with subsequent permanent blindness.

Ocular syphilis should be managed in collaboration with an ophthalmologist; immediate referral to an ophthalmologist is critical if ocular syphilis is suspected. Patients diagnosed with ocular syphilis should be managed according to the STI Treatment Guidelines, 2021 – Neurosyphilis, Ocular Syphilis, and Otosyphilis.

Otosyphilis is caused by an infection of the cochleovestibular system with T. pallidum and typically presents with sensorineural hearing loss, tinnitus, or vertigo. Hearing loss can be unilateral or bilateral, have a sudden onset, and progress rapidly. Otosyphilis can result in permanent hearing loss.

Otosyphilis should be managed in collaboration with an otolaryngologist. Treatment for otosyphilis should follow the STI Treatment Guidelines, 2021 – Neurosyphilis, Ocular Syphilis, and Otosyphilis.

Provider Management for Prevention of Congenital Syphilis

(image links to PDF)

provider management pdf thumbnail


Testing for Syphilis in Pregnancy

Effective prevention and detection of congenital syphilis depend on identifying syphilis among pregnant women as early as possible. Colorado law requires syphilis testing for all persons at their first prenatal visit. CDC recommends third trimester testing at 28 weeks’ gestation and again at delivery for select individuals, including those:

  • Living in a community with high syphilis morbidity; Or
  • Is at heightened risk for syphilis acquisition during pregnancy 
    • Recent history of syphilis, living with HIV, STI diagnosis in the past 12 months, Illicit substance use, sex exchange, multiple partner, or partner with other partners. 

Additionally, CDC recommends syphilis testing for all persons who deliver a stillborn at or greater than 20 weeks’ gestation.  

No mother or newborn infant should leave the hospital without maternal serologic status having been documented at least once during pregnancy. Any woman who had no prenatal care before delivery or is considered at increased risk for syphilis acquisition during pregnancy should have the results of a syphilis serologic test documented before she or her neonate is discharged. A quantitative RPR is needed at the time of delivery to compare with the neonate’s nontreponemal test result.

Treatment for Syphilis in Pregnancy

Persons with a syphilis diagnosis should seek treatment as soon as possible: especially if they are pregnant to prevent serious neonatal complications. Long-acting benzathine penicillin G therapy must be used to treat syphilis during pregnancy to prevent syphilis transmission to the infant. This therapy is extremely effective in preventing CS, with a success rate of up to 98 percent. Persons who are allergic to penicillin should see a specialist for desensitization to penicillin.

Women diagnosed with late syphilis or syphilis of  unknown duration require three doses of benzathine penicillin G given one week apart; if doses are missed or given more than nine days apart, treatment must be restarted. Failure to initiate and complete appropriate syphilis treatment at least 30 days prior to delivery will result in a reported CS case.

For additional information on Diagnostic Considerations, Treatment, and Follow-Up, please visit Syphilis During Pregnancy.

All infants born to women with positive syphilis serology should have non-treponemal serology performed. Additional evaluations and treatment considerations for infants should be made following Congenital syphilis guidelines (CDC).

Evaluation & Treatment of Neonates

Congenital Syphilis (CS) is an infection transmitted from pregnant person to child during pregnancy and/or delivery caused by the bacterium, Treponema pallidum. CS can cause severe illness in infants including premature birth, low birth weight, birth defects, blindness, and hearing loss. It can also lead to stillbirth and infant death.

CS can present with a spectrum of serious manifestations. CS is classified as “early” when the child exhibits symptoms at birth up to their second birthday, and “late” when symptoms start after age two. 

  • Early CS can cause vision or hearing loss, non-viral hepatitis causing jaundice of the skin and eyes, long bone abnormalities, developmental delays, enlargement of the liver and/or spleen (hepatosplenomegaly), severe inflammation of the mucus membranes of the nose (snuffles), rash, anemia, pneumonia, and additional symptoms. 
  • Older children may develop clinical manifestations of late CS, including problems with bone and teeth development, hearing and vision loss, and issues with the central nervous and cardiovascular systems. 

 Evaluation and Treatment of Infants

congenital syphilis chart


In accordance with Regulation 6 CCR 1009-1 all positive syphilis labs must be reported to the Colorado Department of Public Health within 1 working day. Both the provider and laboratory are mandated to report.

How to Report:

  • Fax a STI Disease Report Form to #303-782-5393
  • For other questions, including out of state history, please contact:
    • Adrianna Hervey, Surveillance & Case Ascertainment Manager
    • Desk: 303-692-2694 Voice: 720-263-0415 
    • Email: adrianna.hervey@state.co.us

The National Network of STD Clinical Prevention Training Center offers free case consults. To request a provider consult, visit here.

See this Google Drive folder for the toolkit.