There is very little chance of a problem from having a blood sample
taken from a vein.
- You may get a small bruise at the site. You
can lower the chance of bruising by keeping pressure on the site for several
- In rare cases, the vein may become swollen after the blood
sample is taken. This problem is called phlebitis. A warm compress can be used
several times a day to treat this.
- Ongoing bleeding can be a
problem for people who have bleeding disorders. Aspirin, warfarin (Coumadin), and
other blood-thinning medicines can make bleeding more likely. If you have
bleeding or clotting problems, or if you take blood-thinning medicine, tell
your doctor before your blood sample is taken.
Sore or skin sample
There is very little risk of complications from having a sample
taken from an open sore (chancre), skin rash, or mucous membrane.
Spinal fluid sample
There is little risk linked with having a lumbar puncture to
obtain a spinal fluid sample for syphilis testing. To learn more, see
Syphilis tests detect
antibodies in blood or body fluid or tissue to the
bacterium that causes syphilis (Treponema pallidum).
Results are usually available in 7 to 10 days.
Darkfield microscopic examination
No syphilis bacteria are seen.
Syphilis bacteria are seen.
Syphilis tests of blood and spinal fluid
No antibodies to syphilis are present. This is called a
nonreactive or negative result.
Antibodies to syphilis bacteria are present. This is called a
reactive or positive test.
A result that is not clearly normal or abnormal is called
inconclusive or equivocal.
Venereal disease research laboratory (VDRL) and rapid plasma reagin (RPR) tests
The antibody to the syphilis bacteria (reagin) is not
present. This is called a nonreactive or negative result.
The antibody reagin is present. This is called a reactive or
The accuracy of testing often depends on the
stage of syphilis. Syphilis testing may need to be repeated if initial results
are uncertain or if you have had repeated exposure to syphilis, such as from
repeated unprotected intercourse.