Prostate-Specific Antigen (PSA) by Immunoassay (Screening)
This blood test measures the level of prostate-specific antigen (PSA), a protein produced by the prostate gland. It helps screen for or monitor prostate health, including early signs of prostate cancer.
["PSA tests help detect potential prostate issues early, supporting timely medical evaluation."]
Key facts at a glance
- LOINC
- 68924-0
- Short code
- CA72-4-PF
- Synonyms
- Cancer Ag72-4 Prt-aCnc
- Category
- chemistry
- Sample
- serum
- Container
- Sterile, leak-proof container for peritoneal fluid collection; red-top or serum separator tube if serum is also collected
- Units
- N/A
- Ref low
- 72
- Ref high
- 4
- Critical range
- 0.5 N/A – —
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–99 years
- Method
- Immunoassay (chemiluminescent or electrochemiluminescent immunoassay)
- CPT
- 86316
- SNOMED
- 395692008
- Specimen volume
- 1-2 mL of peritoneal fluid
- Stability
- Refrigerated (2-8°C): 7 days; Frozen (-20°C or below): 30 days; Avoid repeated freeze-thaw cycles
- Hemolysis max
- 100
- Lipemia max
- 100
- Icterus max
- 50
- TAT
- 24–72 hours
- Order
- routine
Why This Test Is Done
Your doctor may recommend a PSA test if you have symptoms like urinary changes, pain in the pelvic area, or if you’re at higher risk due to age, family history, or ethnicity. It’s also used to monitor treatment progress in men with known prostate conditions.
What to Expect Before the Test
No special preparation is needed, but avoid ejaculation for 2–3 days before the test. Wear comfortable clothing and plan to stay for about 15 minutes while the blood is drawn.
What the Test Results Mean
PSA levels vary by age, health, and other factors. While higher levels may raise concern, they don’t always indicate cancer. Your doctor will interpret results in the context of your medical history and symptoms.
Common Causes of Elevated PSA
Elevated PSA can result from prostate inflammation (prostatitis), benign enlargement (BPH), or other conditions. It’s important to discuss any concerns with your healthcare provider.
Reference range
Reference range for CA 72-4 in peritoneal fluid is not well-established; serum reference value is typically <6.0 U/mL. Elevated levels in peritoneal fluid may suggest peritoneal involvement by malignancy.N/A
No special patient preparation required. Inform the laboratory if patient is receiving monoclonal antibody therapy or has recently undergone surgery, as these may affect results.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance: PSA Testing in Prostate Health
Short name
PSA Screening
Frequently asked questions
What might cause my PSA level to be higher than expected?
How often should I get a PSA test if I have no symptoms?
Does diet or medications affect PSA levels?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 17, 2026. · Read our editorial policy