Syphilis: Test and Diagnosis

1st order laboratory parameters – obligatory laboratory tests.

• Point-of-care testing (POCT) for smear pathogen detection from ulcerated or weeping lesions by nucleic acid amplification test (NAAT); this is intended to largely replace microscopic pathogen detection (dark-field microscopy) by their higher specificity and sensitivity.
• Direct microscopic detection of Treponema pallidum by dark-field technique or fluorescence microscopy (DFA-TP) from irritant secretions (only in primary effect and weeping epithelial lesions in the secondary stage).
• Serological examinations (see below); method of choice.
• CSF puncture (collection of cerebrospinal fluid by puncture of the spinal canal) for CSF diagnosis (from stage secondary syphilis!) – in all patients with neurological/psychiatric symptoms.
• HIV test (in the case of unknown HIV status).

Serological tests used in the diagnosis of syphilis include the following procedures:

• Treponema pallidum hemagglutination or particle agglutination test (TPHA or TPPA, respectively) as a screening test [positive: 2 to 3 weeks post infection; reactivity lifelong: so-called “seroscar”]; if positive, confirmatory test required:
  • Fluorescence absorption tests (IgG-/IgM-FTA-Abs test) or.
  • IgG/IgM immunoblot

  Detection of IgM antibodies is indicative of active, acute syphilis.

• 195-FTA IgM test (like FTA Abs test, only specific for fresh infections).
• VDRL microflocculation reaction (antibody screening test; VDRL = Venereal Disease Research Laboratories) or. RPR test (Rapid plasma reagin card test) or IgM ELISA for quantitative antibody determination – as an activity marker and for follow-up; in the first year after the start of therapy, follow-up controls are recommended at three-month intervals [over years usually steadily regressive titer course or a constant titer; after therapy: primary and secondary stage: titers fall below the detection limit within a few months; in late latency or in the tertiary stage: positive findings often still observed for years].
• FTA-Abs test (fluorescent treponema antibody absorbance test; antibody screening test).
• TPI test (Treponema pallidum immobilization test or Nelson test; no longer performed as a standard procedure).
• Treponema-pallidum (PCR) – is reserved for special questions.

The direct or indirect detection of the bacterium “Treponema pallidum” is notifiable according to the Infection Protection Act (IfSG).2nd order laboratory parameters – depending on the results of the medical history, physical examination, etc. – for differential diagnostic clarification.

• Bacteria
  • Chlamydia trachomatis (lymphogranuloma venereum) – serology: Chlamydia trachomatis, HSV types 1 & 2.
  • Neisseria gonorrhoeae (gonorrhea, gonorrhea) – genital swab for pathogens and resistance, specifically for Neisseria gonorrhoeae.
  • Ureaplasma urealyticum
• Viruses
  • HIV (AIDS), herpes simplex virus type 1/2 (genital herpes).
  • Herpes simplex virus type 1/2 (HSV types 1 and 2; genital herpes),
  • Human papilloma virus [HPV] (condylomata acuminata).
• Fungi/Parasites
  • Fungi: Candida albicans et al. Candida species genital smear – pathogen and resistance.
  • Trichomonas vaginalis (trichomoniasis, colpitis) – antigen detection.
• CSF puncture (collection of cerebrospinal fluid by puncture of the spinal canal) for CSF diagnosis – in the case of concomitant HIV infection, in severe HIV-related immunodeficiency even without the presence of neurological symptoms occur (< 200 CD4 cells / µl).

Further notes

• Incidental findings in syphilis: transaminases ↑, high alkaline phosphatase (AP).
• Coinfection with HIV in consideration!
• In the case of untreated HIV infection:
  • Specific tests may be falsely negative
  • Cardiolipin antibody test may be false positive