PROSTATE SPECIFIC ANTIGEN (PSA) RATIO, FREE/TOTAL (CALCULATION)
Test Code: None
When tPSA is >4 μg/L, a fPSA/tPSA ratio of >0.25 is associated with an increased probability of being cancer-free. As the fPSA/tPSA ratio decreases, the probability of prostate cancer increases.
When tPSA is <4 μg/L, a lower fPSA/tPSA cutpoint of 0.10 detects more cancers.
When tPSA is above 10 μg/L, the risk of prostate cancer is relatively high and use of fPSA/tPSA ratio is not recommended as it provides little additional discriminating power.