Clinical laboratories in Donostia, Gasteiz and Bilbao
RPS 131/24Privacy
Combined pathway

Sexually transmitted infection serology

Tests antigens or antibodies for infections such as syphilis, hepatitis B, hepatitis C and HIV, according to the requested profile.

SampleVenous blood.
FastingFasting is usually not required.
Indicative turnaroundSome tests can be reported rapidly; reactive or equivocal findings require confirmation and more time.
PathwayCombined pathway
Available atDonostia · Gasteiz · Bilbo

Why it is performed

  • Screen after exposure, with symptoms, during pregnancy, with a new partner or as part of a sexual-health check.
  • Distinguish past infection, vaccination, immunity or current infection according to the specific marker.
  • Complete diagnoses that cannot be resolved by a single test.

How it is performed

Venous blood is collected. The profile is defined before sampling: there is no single universal 'complete STI test', because each infection needs its own markers and sometimes a different specimen.

Preparation

  • Give the date and type of exposure, hepatitis vaccination history and previous tests or treatment.
  • Blood serology does not replace chlamydia/gonorrhoea PCR or sampling of lesions when appropriate.
  • Repeat testing after the detection window or confirmatory testing may be required.

How Askabide processes it

Combined pathway

Immunoassays for antigens and/or antibodies. Reactive results are interpreted by marker and referred or completed with confirmatory methods when required by the protocol.

Part is performed at Askabide and another phase or confirmation is processed externally.

Results and indicative intervals

Intervals vary by method, analyser, reagent, units, age, sex, pregnancy, menstrual-cycle phase and reference population. The valid interval is the one printed on the laboratory report.
Parameter or resultIndicative referenceHow it is interpreted
Non-reactive/negativeDepende del marcadorThe marker is not detected, but a detection window may apply.
Reactive/positiveInterpretación específicaMay indicate infection, past contact or immunity depending on the test; confirmation is often required.
Indeterminate/equivocalRepetición/confirmaciónA new sample, repeat test or different method may be needed.

Important limitations

  • Markers do not share the same detection window or meaning.
  • A single result may be insufficient to distinguish active infection, past infection or vaccination.
  • Interpretation requires exposure timing, symptoms, vaccination and other tests.
This website provides general information about clinical laboratory tests and diagnostic procedures. It does not replace an individual clinical assessment or the interpretation of the report issued by the laboratory.
Published reference values are indicative and may vary according to the method, equipment, units and individual characteristics.