Contact us | Chinese

More hopes, more possibilities, and more lifeness.

* 搜索范围仅限本站产品及新闻版块内容

News

Home » News

Prostate-Specific Antigen (PSA) Blood Test

Time: 2019-10-11

Prostate-Specific Antigen (PSA) Blood Test

 

What is the PSA test?

Prostate-specific antigen, or PSA, is a protein produced by normal, as well as malignant, cells of the prostate gland. The PSA test measures the level of PSA in a man’s blood. For this test, a blood sample is sent to a laboratory for analysis. The results are usually reported as nanograms of PSA per milliliter (ng/mL) of blood.

The blood level of PSA is often elevated in men with prostate cancer, and the PSA test was originally approved by the FDA in 1986 to monitor the progression of prostate cancer in men who had already been diagnosed with the disease. In 1994, the FDA approved the use of the PSA test in conjunction with a digital rectal exam (DRE) to test asymptomatic men for prostate cancer. Men who report prostate symptoms often undergo PSA testing (along with a DRE) to help doctors determine the nature of the problem.

In addition to prostate cancer, a number of benign (not cancerous) conditions can cause a man’s PSA level to rise. The most frequent benign prostate conditions that cause an elevation in PSA level are prostatitis (inflammation of the prostate) and benign prostatic hyperplasia (BPH) (enlargement of the prostate). There is no evidence that prostatitis or BPH leads to prostate cancer, but it is possible for a man to have one or both of these conditions and to develop prostate cancer as well.

supplements to lower psa levels

What Are Normal PSA Levels?

There’s no such thing as a normal PSA for any man at any given age, but most men with prostate cancer have a higher than normal level. In general:

  • Safe: 0 to 2.5 ng/mL
  • Safe for most: 2.6 to 4 ng/mL. Talk with your doctor about other risk factors
  • Suspicious: 4 to 10 ng/mL. There’s a 25% chance you have prostate cancer.
  • Dangerous: 10 ng/mL and above. Talk to your doctor right away. There’s a 50% chance you have prostate cancer.

How Is The PSA Screening Test Done?

The test involves taking blood, usually from your arm. The doctor will send the sample to a lab. Results most often come back within several days.

When Should I Have My PSA Levels Tested?

The first thing to do is talk to your doctor about the pros and cons of prostate cancer screening before you decide whether to be tested. Don’t get tested until you have that talk. Opinions differ about when you should do that.

The American Cancer Society says to get tested at age:

  • 40 or 45 if you’re at high risk
  • 50 if you’re at average risk

The American Urological Association suggests:

  • Under 40: No screening
  • 40 to 54: No screening if you’re at average risk. If you’re at a high risk, you and your doctor can decide.
  • 55 to 69: Screening if your doctor suggests
  • Over 70 or less than a 10-15 year life expectancy: No screening

The U.S. Preventive Services Task Force says:

  • 55 to 69: Men with prostate cancer risks may need testing.

If your doctor thinks you might have prostate cancer based on either a PSA level or a rectal exam, a biopsy is the next step. This is a test where the doctor takes a small amount of tissue from your prostate and sends it to a lab for tests. It’s the only way to be sure you have cancer.

natural supplements to lower psa levels

What Does a High PSA Level Mean?

High PSA levels could be a sign of prostate cancer or a different condition like prostatitis or an enlarged prostate.

Other things can affect your PSA level:

  • Age. Your PSA will normally go up slowly as you get older, even if you have no prostate problems.
  • Medications. Some drugs may affect blood PSA levels. Tell your doctor if you’re taking dutasteride(Avodart) or finasteride (Propecia or Proscar). These drugs may falsely lower PSA levels by half of what they should be.
  • If your PSA level is high, your doctor may suggest that you get a prostate biopsy to test for cancer.
  • Newer PSA tests may help the doctor decide if you need a biopsy. But know that doctors don’t always agree on how to use or understand the results of these tests.

Alternative PSA Testing

  • Percent-free PSA. PSA takes two major forms in the blood. One is attached to blood proteins. The other moves around freely. The percent-free PSA test shows how much PSA moves freely compared to the total PSA level. The amount of free PSA is lower in men with prostate cancer. If your PSA results are in the borderline range (4 to 10), a low percent-free PSA (less than 10%) means there’s about a 50% chance you have prostate cancer. You should probably have a biopsy. Some doctors suggest biopsies for men whose percent-free PSA is 20 or less.
  • PSA velocity. The PSA velocity isn’t a separate test. Instead, it’s a measure of the change in your PSA levels over time. Even when the total PSA value isn't higher than 4, a high PSA velocity (a rise of more than 0.75 ng/mL in 1 year) means you might have cancer and should consider a biopsy.
  • Urine PCA3 test. This urine test looks for a mix of genes that shows up in 50% of PSA-tested men with prostate cancer. It's another tool to decide if you need a biopsy.

bph

Limitations of the test

The limitations of PSA testing include:

  • PSA-raising factors. Besides cancer, other conditions that can raise PSA levels include an enlarged prostate (benign prostatic hyperplasia, or BPH) and an inflamed or infected prostate (prostatitis). Also, PSA levels normally increase with age.
  • PSA-lowering factors. Certain drugs used to treat BPH or urinary conditions, and large doses of certain chemotherapy medications, may lower PSA levels. Obesity can also lower PSA levels.
  • Misleading results. The test doesn't always provide an accurate result. An elevated PSA level doesn't necessarily mean you have cancer. And many men diagnosed with prostate cancer have a normal PSA level.
  • Overdiagnosis. Studies have estimated that between 23 and 42 percent of men with prostate cancer detected by PSA tests have tumors that wouldn't result in symptoms during their lifetimes. These symptom-free tumors are considered overdiagnoses — identification of cancer not likely to cause poor health or to present a risk to the man's life.

Potential risks

The potential risks of the PSA test are essentially related to the choices you make based on the test results, such as the decision to undergo further testing and treatment for prostate cancer. The risks include:

  • Biopsy issues. A biopsy is a procedure that carries its own risks, including pain, bleeding and infection.
  • Psychological effects. False-positive test results — high PSA levels but no cancer found with biopsy — can cause anxiety or distress. If you are diagnosed with prostate cancer, but it appears to be a slow-growing tumor that doesn't result in illness, you may experience significant anxiety just knowing it's there.

best natural supplement for bph

Using the PSA Blood Test After Prostate Cancer Diagnosis

Although the PSA test is used mainly to check for prostate cancer, it can also help your doctor:

  • Choose a treatment. Along with an exam and tumor stage, the PSA test can help determine how advanced a prostate cancer is. This may affect treatment options.
  • Check treatment success. After surgery or radiation, the doctor can watch your PSA level to see if the treatment worked. PSA levels normally fall if all of the cancer cells were removed or destroyed. A rising PSA level can mean that prostate cancer cells are present and your cancer has returned.

If you choose a watchful waiting approach to treatment, your PSA level can tell your doctor if the disease is progressing. If so, you’ll need to think about active treatment. During hormone therapy, the PSA level can show how well the treatment is working and when it’s time to try another treatment.