{"id":"psa-free","name":"PSA, Free","shortName":"Free PSA","aliases":["Free PSA","fPSA","Prostate Specific Antigen, Free","Prostate Specific Ag, Free","Free Prostate Specific Antigen","PSA libre","Free Prostate-Specific Antigen","PSA, Free, Serum","Free PSA, Serum","Prostate Specific Ag Free","Prostate-Specific Antigen, Free","Free PSA (Unbound)"],"abbreviations":["fPSA","free PSA"],"loinc":[{"code":"10886-0","primary":true},{"code":"83113-1","primary":false}],"specimen":"serum-or-plasma","units":[{"ucum":"ng/mL","display":"ng/mL"},{"ucum":"ug/L","display":"µg/L"}],"referenceRanges":[],"review":{"status":"ai-verified","label":"AI-verified against cited sources. Awaiting expert review","lastReviewed":"2026-10-03"},"summary":"The part of the PSA in your blood that is not attached to other proteins. It is read next to total PSA, not by itself.","url":"https://bloodtesttracker.com/markers/psa-free","notice":"Information, not medical advice. Ranges differ between labs, so the range on your own report is the one your result is judged against."}