CDC Laboratory Recommendations for Syphilis Testing, United States, 2024

Area of Science:

• Clinical microbiology
• Infectious diseases
• Public health

Background:

• Syphilis diagnosis traditionally relies on serologic testing detecting immune responses to Treponema pallidum.
• Existing serologic tests include nontreponemal and treponemal assays, requiring combined use for accurate interpretation.
• Direct detection methods for Treponema pallidum are evolving from microscopy to molecular techniques.

Purpose of the Study:

• To provide comprehensive, updated CDC recommendations for laboratory testing in syphilis diagnosis.
• To guide the selection and implementation of various diagnostic methodologies.
• To inform clinical laboratory directors, staff, clinicians, and public health officials.

Main Methods:

• Review and synthesis of current evidence and expert opinion on syphilis diagnostic tests.
• Categorization of tests into serologic (nontreponemal, treponemal) and direct detection methods.
• Consideration of laboratory automation, algorithm development, and point-of-care testing.

Main Results:

• New recommendations encompass both established and emerging diagnostic approaches for syphilis.
• Emphasis on the combined use of different test types for accurate diagnosis of active or past infections.
• Highlights the evolution towards automated and molecular diagnostic tools.

Conclusions:

• Updated recommendations aim to improve the accuracy and efficiency of syphilis diagnosis.
• Increased availability of sensitive and specific point-of-care tests could enhance screening programs.
• Future revisions will incorporate advancements in syphilis clinical laboratory science.