Prostate-Specific Antigen (PSA) Test

What is a prostate-specific antigen test?

The PSA or prostate-specific antigen is a chemical (protease) secreted by the prostate gland which serves the function of liquefying semen upon ejaculation. A major chunk of PSA is found in the semen and very small amount of this substance gets mixed with the bloodstream. This means under normal conditions, the PSA level should be low. A PSA test aims to measure the level of this substance in the blood to detect if the prostate gland is functioning normally or not.

How does it help in prostate cancer screening?

Men who fall into higher risk pool for prostate cancer, such as those with immediate blood relative who have been diagnosed with this condition or men with specific ethnicities such as African-American, should ideally get screened for prostate cancer yearly. This screening is usually done post the age of 50 years. PSA level is used to check the health of the prostate gland. If the PSA level is high, it could indicate prostate cancer.

How common is prostate cancer?

Prostate is a small gland that is present just below the urinary bladder in men. Its primary function is semen production. Prostate cancer is considered to be quiet deadly as it kills 1 man every 18 minutes (globally). In the USA alone there are almost 3 million men affected by this condition. It is very common in men above the age of 65 years.

How does one get prostate cancer?

There are several factors which can significantly increase the risk of prostate cancer. These are – age (>65 years), ethnicity (African-Americans), heredity, unhealthy diet (rich in red meat & trans fats), obesity, tobacco intake, and toxic chemical exposure. It may also occur as a result of an untreated STD (chlamydia or gonorrhea) or even a vasectomy.

What are the symptoms of prostate cancer?

The tell-tale signs of prostate cancer are – severe pain during urination, increased urge to urinate, feeling of full bladder, erectile dysfunction, loss of bladder control, and radiating pain in the pelvic region.

Who should undergo a PSA test?

If you are someone who falls in the risk pool mentioned above, you should undergo a PSA test. If you are above the age of 50 years and/or have a high risk of prostate cancer, you should discuss with your doctor and get a PSA test done. Also, if you have been experiencing the classic signs of prostate cancer such as painful urination and erectile dysfunction, it would be wise to get this test done.

How is a prostate-specific antigen test conducted?

PSA test is a simple blood test. You needn’t fast before a PSA test. The test is conducted by drawing a small amount of blood from your arm and the sample is sent for analysis.

How does one prepare for a prostate-specific antigen test?

There is no special preparation required for this blood test. You needn’t be on an empty stomach before undergoing a PSA test.

When can I get my PSA test result?

It takes around 1 week to 10 days for the PSA blood test results to be out. In some cases, the waiting period was even 2 weeks.

How much does a PSA test cost in India?

The cost of a PSA test in India lies in the range Rs. 800-1000/-.

What are normal PSA levels?

PSA level is expressed in terms of nanogram of PSA per milliliter of blood or ng/mL.
There is no such thing as a fixed normal level of PSA for a man belonging to any age group. It has been observed that men with higher PSA level tend to get diagnosed with prostate cancer. PSA level readings have been categorized as:

My PSA level is high. What does it mean?

As mentioned above, if your PSA levels lie fall in the suspicious and dangerous categories, you have a 25-50% chance of being diagnosed with prostate cancer. However, this test alone is not an indicator of the presence of prostate cancer. There are other factors too that can lead to an elevated PSA level in the body. Conditions such as prostatitis (inflammation of the prostate gland) or urinary tract infection can also lead to high PSA level. A high PSA level could indicate an enlarged prostate, an infection of the prostate, or prostate cancer.

What does a low PSA level indicate?

Studies have revealed that 15% of men with low PSA level ( < 4 ng/mL) who underwent a biopsy of the prostate tissues were detected with prostate cancer. This means that for any man with PSA level more than 1 ng/mL there is no PSA level that directly points to prostate cancer. PSA level is not the only test that can determine the presence or absence of prostate cancer. A lot of factors need to be considered before firmly establishing the onset of cancer.

What are the benefits and risks associated with the PSA test?

Benefits of PSA test

It can help establish to some extent the probability of prostate cancer.

It can also help detect other issues with the prostate gland.

PSA test can also tell how advanced prostate cancer is. This helps in determining the exact treatment protocol.

PSA test after cancer treatment can help establish the success of the treatment.


Risks/limitations associated with PSA

PSA tests may help establish the onset of prostate cancer but early detection, in this case, doesn’t reduce the risk of death.

At times, PSA test may help detect small tumors in the prostate gland which are non-cancerous, thus, non-threatening. Treatment of such tumors exposes the patient to harmful side-effects.

PSA test may give false-positive or false-negative results.

Also, biopsy performed following a high PSA test can lead to infections and bleeding

Are there any alternatives to PSA?

There are several variations to the usual PSA test. These are:

PSA velocity: This measures the rate of change of PSA level with respect to time. High PSA velocity indicates an aggressive form of cancer.

Free PSA: PSA is found in the bloodstream in two forms- attached (to blood proteins) or free. If one has a high PSA level but a low percentage of free PSA, it is indicative of prostate cancer.

What is free PSA and what does it indicate?

Free PSA reading shows the percentage of PSA unattached to the blood proteins. If a man’s PSA level lies in the borderline range ( 4-10 ng/mL), he must undergo a free PSA test too to gain a clearer picture. A high PSA level and low free PSA point towards a higher risk of prostate cancer and necessitate a biopsy.

Can PSA test be used for men who have been treated for prostate cancer?

Yes, in many cases PSA test is used to determine the success of prostate cancer treatment. A high PSA level post-treatment could mean the recurrence of cancer. This relapse can happen within months or years of the treatment.

How accurate is the PSA test?

Though PSA can help determine if there are issues with the prostate gland or not, this test alone cannot guarantee the presence or absence of prostate cancer. There is no specific cut-off or threshold limit of PSA that directly correlates prostate cancer.
Additionally, it has been observed that the PSA test can yield both false-positive and false-negative results. Thus, the PSA test alone shouldn’t be counted as a sure shot parameter for assessing the presence of prostate cancer.

What factors can influence the PSA level in a man?

Advanced age
Pelvic injury
Prostate infection
Recent biopsy
Use of catheter
Intake of testosterone supplements
Urinary tract infection
Sexual intercourse (with 24 hours)