PSA (Prostate Specific Antigen) - Free – BC264
♂️ Prostate Cancer Risk AssessmentReport: Same Day
Sample Type: Blood (Serum)
Test Code: BC264
The Free Prostate Specific Antigen (Free PSA) test measures the amount of PSA that circulates "unbound" to other proteins in the blood. It is performed alongside a Total PSA test and is primarily used to help differentiate between prostate cancer and benign prostate conditions (like BPH) when the Total PSA level is in the borderline "gray zone."
✔ Helps in the risk stratification for prostate cancer, especially when Total PSA is between 4-10 ng/mL.
✔ The result is reported as a % Free PSA ratio (Free PSA / Total PSA).
✔ A lower % Free PSA suggests a higher risk of cancer, helping doctors decide on the necessity of a biopsy.
✔ Important to avoid certain activities before the test.
Free PSA: Adding Clarity to a Complex Picture
The Total PSA test is a standard screening tool for prostate health, but it has a well-known limitation: an elevated level can be caused by prostate cancer, but it can also be caused by benign (non-cancerous) conditions like Benign Prostatic Hyperplasia (BPH) or prostatitis. This often creates a diagnostic dilemma, especially when the Total PSA is in the borderline "gray zone" (typically 4.0 to 10.0 ng/mL).
The Free PSA test adds a crucial layer of information. PSA in the blood exists in two main forms: one that is complexed or bound to other proteins, and one that is "free." Research has shown that:
- In prostate cancer, a higher proportion of the PSA is in the bound form, which means the percentage of free PSA is lower.
- In benign conditions like BPH, a higher proportion of the PSA is in the free form, meaning the percentage of free PSA is higher.
The Power of the % Free PSA Ratio
The lab uses both the Free PSA and Total PSA results to calculate the **% Free PSA ratio**. This ratio helps the urologist to stratify risk and make a more informed decision about whether to recommend a prostate biopsy:
- A Low % Free PSA (e.g., < 10%) is associated with a higher probability of prostate cancer. A biopsy is more likely to be recommended.
- A High % Free PSA (e.g., > 25%) is associated with a lower probability of cancer, suggesting a benign condition like BPH is the more likely cause of the elevated Total PSA. A "watchful waiting" approach might be recommended instead of an immediate biopsy.
This test does not diagnose cancer, but it is an invaluable tool for risk assessment, helping to avoid unnecessary invasive procedures in some men while identifying those who need them most.
Frequently Asked Questions (FAQ)
The Free PSA test is ordered to add clarity when your Total PSA is in the borderline range (4-10 ng/mL). The % Free PSA ratio helps your doctor better estimate the probability that your high PSA is due to cancer versus a benign condition like an enlarged prostate (BPH).
A low percentage of free PSA (typically below 10%) is associated with a higher risk of having prostate cancer and makes a recommendation for a prostate biopsy more likely.
A high percentage (typically above 25%) indicates a lower probability of cancer and suggests a benign condition is more likely. However, it does not completely rule out cancer. Your urologist will make a final decision based on all factors.
Fasting is not generally required. However, it's very important to avoid ejaculation and vigorous exercise (like cycling) for at least 48 hours before the test, as these can temporarily raise PSA levels. Also, inform the lab if you have had a recent prostate exam or biopsy.