PSA Free & Total Test
A PSA free and total test measures two forms of prostate-specific antigen in the same sample: the total amount and the portion that circulates freely. Together they give a clinician more context. Like PSA generally, this is a screening and monitoring marker, not a way to diagnose cancer on its own.
About this test
Prostate-specific antigen, or PSA, is a protein made by the prostate that can be measured in the blood. It travels in more than one form: some is bound to other proteins, and some moves freely.
The test uses a routine blood draw at a patient service center. A phlebotomist collects a sample from a vein in the arm and sends it to the laboratory, which measures both forms from the same sample.
Who might consider this test?
- Others use it as part of ongoing monitoring under a clinician's care.
Test details
| Quest code | 31348 |
|---|---|
| Methodology | Immunoassay |
| Sample type | 2 mL frozen serum |
| Collection | Quest patient service center |
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Additional details
What this test looks at
This test describes prostate activity through two related measures rather than one. Total PSA captures the overall amount of the protein, and free PSA captures the unbound portion. Clinicians sometimes find the relationship between the two forms more informative than either measure by itself, which is the reason for ordering them together.
Both forms reflect prostate tissue, not hormone balance, and neither is a picture of the gland. They are proteins associated with the prostate, and they are best understood as complementary data points a clinician can weigh together.
What this test can and can't tell you
Measuring both free and total PSA gives a clinician more context, but it still cannot diagnose cancer or rule it out. This remains a screening and monitoring tool. It can help a clinician judge whether a closer look is worthwhile; it does not provide an answer on its own.
PSA in either form can be influenced by benign prostate conditions, recent activity, and certain procedures, and it can be unremarkable even when something is present. A clinician reads the two measures together against age, symptoms, history, and other findings. When a diagnosis is needed, it involves further evaluation such as imaging and sometimes a biopsy, never a blood marker alone.
How the two forms add context
The value of ordering free and total together is in the comparison. Looking at how much of the total is free can give a clinician a more nuanced sense of what the numbers might mean, which is why this pairing is sometimes chosen over total PSA alone.
Even so, the comparison is context, not a conclusion. It helps guide a conversation about next steps and is interpreted alongside everything else a clinician knows about a person.
Order online and a physician order is included — no doctor's visit and no insurance needed. Your sample is collected at a Quest Diagnostics patient service center.
Laboratory results should always be interpreted by a licensed clinician who knows your health history. This page is information about a test, not medical advice.
Frequently asked questions
What does the PSA free and total test measure?
It measures two forms of prostate-specific antigen from one sample: the total amount and the freely circulating portion. Clinicians sometimes find the relationship between them more informative than total PSA alone.
Can this test diagnose prostate cancer?
No. Measuring both forms adds context, but PSA remains a screening and monitoring marker. It cannot diagnose or rule out cancer by itself. A clinician interprets the results together, and a diagnosis involves further evaluation such as imaging and sometimes a biopsy.
Why measure free PSA in addition to total?
Looking at how much of the total PSA is free can give a clinician a more nuanced sense of what the numbers might mean, which is why this pairing is sometimes chosen over total PSA alone. It is still interpreted in context.
Can these markers be affected by things other than cancer?
Yes. Benign prostate conditions, recent activity, and certain procedures can influence PSA in either form, and it can be unremarkable even when something is present. A clinician reads the results against age, symptoms, and history.
Is any preparation needed?
Certain activities and procedures can affect PSA, so a clinician may offer guidance about timing. It is worth following any instructions provided and mentioning recent procedures and current medications.
Can I get the PSA Free & Total test without a doctor's visit or insurance?
Yes. The $189 cash price includes an independent physician's order, so no referral is needed, and insurance is never involved.