The guidelines note that culture, nucleic acid hybridization tests, and nucleic acid amplification testing (NAAT) are available for the detection of both N. gonorrhoeae and C. trachomatis. "Culture and hybridization tests require urethral swab specimens, whereas NAATs can be performed on urine specimens. Because of their higher sensitivity, NAATs are preferred for the detection of C. trachomatis."
• Revised guidance on the evaluation of neurosyphilis. Laboratory diagnosis of neurosyphilis usually depends on various combinations of reactive serologic test results, cerebrospinal fluid cell (CSF) count or protein, and a reactive CSF-Venereal Disease Research Lab [VDRL] test with or without clinical manifestations. "Among persons with HIV infection, the CSF leukocyte count usually is elevated (greater than 5 white blood cell count/mm3); using a higher cutoff (greater than 20 white blood cell count/mm3) might improve the specificity of neurosyphilis diagnosis," the guidelines state. "The CSF-VDRL might be nonreactive even when neurosyphilis is present; therefore, additional evaluation using FTA-ABS [fluorescent treponemal antibody absorbed] testing on CSF can be considered. The CSF FTA-ABS test is less specific for neurosyphilis than the CSF-VDRL but is highly sensitive; neurosyphilis is highly unlikely with a negative CSF FTA-ABS test."
Dr. Workowski and Dr. Berman emphasized that the guidelines "should be regarded as a source of clinical guidance and not prescriptive standards; health care providers should always consider the clinical circumstances of each person in the context of local disease prevalence. They are applicable to various patient-care settings, including family-planning clinics, private physicians’ offices, managed care organizations, and other primary care facilities."