Following reports from the US Centers for Disease Control and Prevention (CDC) regarding an increase in syphilis infections among all patients aged ≥15 years, a group of researchers from Las Vegas presented guidance for screening, diagnosing, and treating patients who are at risk for sexually transmitted infections (STIs) in the Journal of the American Academy of Physician Assistants.1

The total number of syphilis infection (Treponema pallidum) rose by 13.3% between 2017 and 2018 and by 34% among women, according to the CDC.2 Congenital syphilis cases increased by 185% between 2014 and 2018; researchers noted that in 80% of cases, women who contract syphilis up to 4 years before pregnancy will transfer the infection to the fetus.2

Researchers reiterated the CDC’s syphilis screening protocol for all pregnant women at their first prenatal visit and indicated that women at high risk of transferring the infection to the fetus be screened again at 28 to 32 weeks and at delivery.2,3 If a patient was not screened during her pregnancy or had a stillbirth after 20 weeks gestation, the authors recommend screening at delivery.

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In cases where suspicion for syphilis is high, researchers advise re-testing a patient after 3 months as false-negative results on serologic tests are common in the first 3 months of infection. Since single, nontrepomenal tests can miss a case of late latent syphilis or produce a false-positive result when used alone, the authors recommended confirmatory treponemal tests in both low- and high-risk populations using a reverse syphilis algorithm rather than the traditional algorithm.4

The rapid syphilis serologic test may be a useful tool for clinicians in areas of limited resources and laboratory capabilities, especially in settings where patients are frequently lost to follow-up, according to the authors. Though rapid test results do not distinguish between active and previously treated syphilis infection, rapid tests can be effective for screening pregnant women in areas with a high prevalence of untreated syphilis.

The authors recommend following CDC guidelines for treatment; clinicians should choose the most appropriate intervention based on the patient’s specific phase of disease. Pregnant patients should be aware of the risk of early labor caused by syphilis treatment and are advised to contact their obstetrician if they develop symptoms. Syphilis patients should follow up with their clinicians and undergo serologic testing at 6 and 12 months after treatment.

“Because of the increasing rates of syphilis infection, clinicians must more actively screen patients who are at risk of STI transmission based on history and clinical presentation,” researchers said. “Clinicians should include syphilis testing during STI screening for all sexually active patients to help curb the morbidity associated with undiagnosed and untreated disease.”


  1. Sanchez L, Harris T, Duford A, Duran N. Recognizing and limiting syphilis to prevent congenital syphilis. JAAPA. 2020;33(8):44-47.
  2. Centers for Disease Control and Prevention. Sexually transmitted disease surveillance 2018. Accessed September 1, 2020.
  3. Centers for Disease Control and Prevention. 2015 Sexually transmitted diseases treatment guidelines: syphilis. Accessed September 1, 2020.
  4. Dunseth CD, Ford BA, Krasowski MD. Traditional versus reverse syphilis algorithms: a comparison at a large academic medical center. Pract Lab Med. 2017;8:52-59.