Clinical significance
Treponema pallidum is a spirochaete, i.e. a long spiral-shaped bacterium, that causes syphilis, an infection transmitted sexually (acquired form) or across the placenta from an infected mother (congenital form). Congenital syphilis can be passed on by a pregnant woman from the 16th week of pregnancy, when the treponemes cross the placental barrier and reach the fetus.
During acute infection, specific class M antibodies (IgM) rise, followed by IgG, which remain for life.
Clinical indications
Suspected infection, screening (pregnancy)
Sample type
The patient must have a blood sample taken.
Preparation
You must fast for at least 8 hours; a small amount of water is allowed. You must have been standing or sitting upright for at least 30 minutes.
Notes
Total Ig absent, IgM absent: no exposure. If there is clinical uncertainty, patients should be monitored over time.
Total Ig present, IgM absent: past infection.
Total Ig absent, IgM present: infection at a very early stage.
Total Ig present, IgM present: acute infection