Laboratory Test Information Guide

Details for Free Prostate Specific Antigen, Plasma/Serum

Test Name: Free Prostate Specific Antigen, Plasma/Serum
Alternate Name(s): fPSA
Free PSA
Laboratory: Core
Specimen Type: Adult:
4.5 mL Light Green top (Li-Heparin) Vacutainer tube

Red, Gold, or Lavender (EDTA) top tubes are also acceptable
Collection Information: Minimum volume of plasma or serum required is 700 L for adult samples samples.
Test Schedule: As required
Turnaround time from when specimen
is received in testing laboratory:
4 hours
Reference Range: free PSA (g/L): no reference interval available

free PSA ratio: The probability of prostate cancer (PCA) is inversely related to the ratio and varies with age. When the total PSA is 4-10 g/L and the free PSA ratio is ≤0.10, the probability of PCA is 49-65%. When the total PSA is 4-10 g/L and the free PSA ratio is ≥0.26, the probability of PCA is 9-16%.
Effective Date: 2018-03-06
Revised Date: 2021-06-11
Critical Value:  
Interpretive Comments: If the total PSA result is in the range of 4 10 g/L, a free PSA result could be of value in estimating the risk of prostate cancer in a patient with no previous diagnosis.
Special Processing:  
Comments: Biotin may interfere with this test. Samples should not be taken from patients receiving high biotin doses (i.e. > 5 mg/day) until at least 8 hours after the last biotin administration.
Method of Analysis: Roche Electrochemiluminescence
Critical Information Required:  
Storage & Shipment:  
System Codes: 
Referred To:  

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