Overview
STI blood testing detects infections such as HIV, syphilis and hepatitis. It is an important part of comprehensive screening.
What it detects
Blood-borne or serologic markers for HIV, syphilis, hepatitis B and hepatitis C.
Sample type
Blood sample.
When it may be appropriate
Routine screening, exposure, symptoms or partner diagnosis.
Window period considerations
Window periods vary by infection and test; early testing may miss infection.
Test limitations
Does not detect all STIs; some infections require urine or swabs.
Interpretation basics
Results are interpreted with test type, timing and confirmatory algorithms.
Follow-up recommendations
Repeat testing may be needed after recent exposure; positive results need confirmation.
Key points
- Detects HIV/syphilis/hepatitis
- Part of comprehensive screen
- Window periods vary
- Confirmation may be needed
When to seek care
- Routine screening
- Possible exposure
- Partner diagnosis