Understanding PSA Tests for Prostate Health

The prostate-specific antigen (PSA) test is commonly used to screen for prostate cancer and other prostate conditions. This blood test measures the level of PSA, a protein produced by the prostate gland. Elevated PSA levels may indicate prostate abnormalities. However, PSA levels can be raised due to various reasons. Understanding what PSA tests measure, normal ranges, and how to interpret results is important for prostate health.

What is PSA?

PSA, also called kallikrein-3 (KLK3), is a glycoprotein enzyme produced by the epithelial cells of the prostate gland. Trace amounts of PSA are present in the blood and semen of all adult males. Low PSA levels are also found in amniotic fluid, breast milk, the endometrium and breast tissue of females.

PSA helps liquefy semen after ejaculation to allow sperm mobility. It is produced in very small amounts in healthy prostates but often rises with prostate cancer and other prostate disorders. PSA levels in the blood typically increase as men age, even if the prostate is cancer-free.

Types of PSA Tests

There are two main types of PSA tests:

Total PSA Test

This test measures the level of total PSA in the blood, including both bound and free PSA. Most PSA in the blood is bound to proteins like alpha-antichymotrypsin and alpha-2-macroglobulin.

The total PSA test is the standard test used to screen for possible prostate cancer.

Free PSA Test

This test measures only the free PSA floating unbound in the blood. It is often used as a follow-up when total PSA levels are moderately elevated between 4-10 ng/mL.

Higher percentages of free PSA indicate a lower likelihood of prostate cancer. Lower percentages of free PSA raise suspicion for cancer.

Purpose of PSA Testing

PSA testing has several clinical uses:

• Screening for possible prostate cancer
• Helping determine the need for prostate biopsy after elevated PSA
• Monitoring prostate cancer treatment effectiveness
• Tracking recurrence after prostate cancer treatment
• Diagnosing prostatitis (inflammation of the prostate)
• Identifying benign prostatic hyperplasia (enlarged prostate)

Routine PSA screening for prostate cancer remains controversial. It can detect cancer early but also leads to overdiagnosis and overtreament of less aggressive tumors. Patients should discuss the pros and cons of PSA screening with their doctor.

Normal PSA Ranges

PSA levels below 4.0 ng/mL are generally considered normal. However, there is no definitive cutoff distinguishing “normal” from “abnormal.” Doctors evaluate results based on the PSA level itself plus factors like:

• PSA levels over time
• PSA density (level divided by prostate volume)
• PSA velocity (rate of change over time)
• Patient age
• Prostate exam findings
• Family history
• Other health conditions

In the past, PSA levels above 4.0 ng/mL often triggered prostate biopsy. Experience has shown the 4.0 ng/mL cutoff is too low, missing aggressive cancers and prompting unnecessary biopsies for benign conditions.

Today, the trend is toward higher PSA thresholds for biopsy, especially in older men and those with other medical problems. Active surveillance is often recommended for early, low-grade prostate cancer.

When PSA Levels Are Elevated

There are several possible causes of elevated PSA besides prostate cancer:

Prostatitis

Prostatitis means inflammation of the prostate gland. It can be caused by bacterial infections but more often has nonbacterial causes. Prostatitis usually raises PSA, which normalizes after treatment.

Benign Prostatic Hyperplasia (BPH)

BPH refers to noncancerous prostate enlargement common in older men. As the prostate grows larger, it produces more PSA, increasing blood levels. Medications shrinking the prostate may lower PSA.

Older Age

PSA levels normally rise as men age, even without prostate disease. This may be due to prostate enlargement or developing conditions like BPH. Age-specific PSA ranges provide guidelines tailored to the patient’s age bracket.

Prostate Biopsy and Procedures

Prostate biopsies, cystoscopy, urinary catheterization, and other invasive procedures can temporarily raise PSA for weeks or months. PSA should be rechecked after full recovery before basing treatment decisions on these results.

Ejaculation

Vigorous sexual activity and ejaculation in the 48 hours prior to PSA testing can elevate results. Patients should avoid ejaculation for two days before a PSA test.

Other Factors

Obesity, medications, urinary tract infections, or other genitourinary conditions may also increase PSA production from the prostate. Lifestyle changes and treating medical issues can lower PSA.

PSA Velocity and PSA Density

Along with the absolute PSA number, doctors also consider:

• PSA Velocity: The rate of change in PSA over time, expressed in ng/mL per year. Prostate cancer often shows a rapid rise in PSA.
• PSA Density: The PSA level divided by the prostate volume. Dense prostate tissue may suggest cancer.

Rising PSA velocity and density indicate increased prostate cancer risk and need for ongoing monitoring.

PSA and Testosterone

Checking blood testosterone levels provides key additional information when interpreting PSA results:

• High testosterone with rising PSA raises concern for aggressive prostate cancer. Testosterone suppression may help control cancer.
• Low testosterone with rising PSA indicates possible castration-resistant cancer. This is a more serious cancer no longer responding to low testosterone.

Heart disease, diabetes, and other conditions often lower testosterone while also raising PSA. Overall health risks should be weighed carefully when considering prostate cancer treatment.

PSA Screening Recommendations

Medical groups advise informed decision-making about PSA screening for prostate cancer:

• Age 40: Men at average risk can have an initial PSA test to establish a baseline. African American men and those with a family history of prostate cancer may start at age 40.
• Age 45-75: Discuss with your doctor whether routine PSA testing is appropriate based on your risk factors and values. Screening is most helpful in this age group for long life expectancy.
• Age over 75: Routine PSA screening is often no longer recommended due to limited benefit for older men. Testing decisions depend on overall health and longevity.

Prostate Biopsy Considerations

Doctors ordering prostate biopsies due to possible cancer should first evaluate the risk-benefit ratio for individual patients. Less aggressive or advanced age prostate cancer often does not require treatment. Biopsy risks like infection should be balanced with the chances of a cancer requiring therapy if found.

PSA Levels May Be Elevated Temporarily or Chronically

 The PSA test can provide valuable information about prostate health. However, results require careful interpretation based on multiple factors. PSA levels may be elevated temporarily or chronically for reasons besides cancer.

Discussing PSA results and prostate exam findings thoroughly with your doctor is important to determine proper follow up. An integrated approach combining PSA with other parameters helps guide wise prostate health decisions.