Prostate-Specific Antigen (PSA)
A prostate-specific antigen (PSA) test is a blood test that measures the level of PSA in a sample of your blood.
A prostate-specific antigen (PSA) test is a blood test that measures the level of PSA in a sample of your blood. PSA is a protein made by your prostate. The prostate is a gland in the male reproductive system. It lies just below the bladder. It makes the fluid part of semen. It's normal to have a low level of PSA in your blood. A high PSA level may be caused by: Prostate cancer An enlarged prostate (also called benign prostatic hyperplasia or BPH) Prostatitis, inflammation (swelling and pain) in the prostate gland Other common prostate problems Urinary tract infections (UTIs) Taking certain medicines A PSA test can't show what is causing abnormal PSA levels. So, if your level is high, you may need other tests. Other names: total PSA, free PSA
Why is this test ordered? It's your choice whether to have a PSA test to screen for cancer. You and your provider may consider your risk for developing a serious cancer that could spread if you don't catch it early. Your risk for serious prostate cancer may be higher depending on your: Age. The risk of prostate cancer increases after age 50. Your family health history. If members of your family have had prostate cancer, your risk may be higher. Your race. Prostate cancer is more common in Black men, who also have a higher risk of developing prostate cancer at a younger age and having more serious disease. You may also have a PSA test if: You have symptoms of a prostate condition, such as: Painful, slow, and/or frequent urination (peeing) Blood in urine or semen Pelvic and/or back pain Urinary incontinence You have prostate cancer. Your provider may use PSA testing to monitor your condition or to see how well treatment is working.
Reference Ranges & Biomarker Tiers
| Commonly used cutoff | Above 4.0 ng/mL | NCI states a PSA above 4.0 ng/mL is considered abnormal and may result in a recommendation for prostate biopsy. |
| No universal threshold | Varies | NCI states there is no single threshold that distinguishes a normal from an abnormal PSA result. Some clinicians apply a higher cutoff for older men and a lower one for younger men, and levels are adjusted for finasteride or dutasteride. |
Reference intervals vary by performing laboratory, assay method, age and sex. Always interpret a result against the interval printed on the report from the laboratory that ran the test. Source for these values: National Cancer Institute (NCI), NIH.
Clinical Interpretation
There is no specific normal or abnormal level for PSA in blood. In general, the higher your PSA level, the more likely it is that you have cancer. But it's possible to have a high PSA without prostate cancer, or a low PSA with prostate cancer. If you had a PSA test for a prostate cancer screening or because you have prostate symptoms: High PSA levels can mean you have prostate cancer or a prostate condition that's not cancer, such as an infection (causing prostatitis) or an enlarged prostate. If your PSA levels are higher than normal, your provider may talk with you about having more tests to diagnose the cause. These tests may include: Another PSA test, more commonly if you don't have any symptoms. PSA levels can go up and down, so it's helpful to see if your PSA levels change over time. A digital rectal exam (DRE). For this test, your provider inserts a gloved, lubricated finger into your rectum to feel your prostate for lumps or anything unusual. A urine test . A sample of your urine is tested for infection. A prostate biopsy. A biopsy is minor surgery. A provider removes samples of tissue from your prostate so it can be studied under a microscope to look for cancer cells. A biopsy is the only way to diagnose cancer. It may be recommended if your provider thinks you may have prostate cancer. If you had a PSA test to monitor prostate cancer or treatment , ask your provider what a high PSA level means. Your provider will usually look at several tests results over time to get a better understanding of your condition. If you have questions about your results, talk with your provider. Learn more about laboratory tests, reference ranges, and understanding results .
Medicare Coverage — diagnoses supporting medical necessity (NCD)
Showing 18 of 51 diagnoses Medicare covers for this test under NCD 190.31. The complete list is in CMS's Lab NCD code list.
Clinical Protocol & Patient Advice
- 1
Avoid ejaculation for 48 hours prior to the blood draw, as it can temporarily raise PSA.
- 2
Avoid heavy bicycle riding immediately before the test to prevent mechanical prostate irritation.
- 3
You will need to avoid having sex or masturbating for 24 hours before your PSA test. That's because releasing semen can increase your PSA levels, which may make your results less accurate. Also, certain medicines may affect your test results, so tell your provider about any medicines you take. But don't stop taking any medicines unless your provider tells you to.
Usage Guidance
- An elevated PSA is not a definitive diagnosis of prostate cancer; many elevations are benign.
- Some cancers do not produce high PSA; clinical correlation with DRE (digital rectal exam) is key.
- Reference ranges vary by laboratory. Always discuss your specific results with a qualified healthcare professional.
Source: MedlinePlus, National Library of Medicine. View the original.
Read from: MedlinePlus (NLM); reference ranges only where NIDDK, NIH ODS or NCI states the value, linked per page — Curated from federal sources. All data sources · How to read the labels