Key takeaways:
- Prostate-Specific Antigen (PSA) testing can be a useful part of prostate cancer screening.
- Many men wonder what can skew a PSA test. Many factors like age and race can influence a man’s baseline PSA levels.
- Medications, infections, digital rectal exams, and other things can temporarily skew PSA results to be higher or lower than baseline.
- An MRI scan helps create a more complete picture of prostate health.
You may know that prostate cancer is the most prevalent cancer (other than skin cancer) found in men1. However, you may not know that if the cancer is found early, before it spreads beyond the prostate, the five-year survival rate is nearly 100 percent2. This means early prostate detection is key in successfully treating prostate cancer.
However, like everything else, the PSA test isn’t perfect. The answer to “What can skew a PSA test?” varies for each individual.”
Knowing these factors can help you schedule your PSA test for higher accuracy and discuss your results more thoroughly with a medical professional.
What Is a PSA Test?
A PSA test is a blood test that measures levels of PSA in blood. PSA is a protein that is produced in the prostate by both healthy and cancerous cells. Higher levels of PSA can indicate problems with the prostate, including cancer.
Although no PSA level can be used to definitively diagnose prostate cancer, most healthcare providers recommend further testing if someone has more than four nanograms of PSA per ml of blood (ng/mL)3.
Normal PSA Score Variations
Many normal variations can influence a PSA test score baseline.
Age is the biggest factor that can influence a PSA score, as the prostate gland enlarges naturally with age, potentially resulting in PSA level changes4.
Race also plays a role in a man’s normal PSA score. Black men who don’t have prostate cancer tend to have higher PSA scores than white men who don’t have prostate cancer5.
Weight can influence a PSA score as well. Studies have shown men without prostate cancer with a higher body mass index (BMI) have a lower PSA level6. This means someone who has a higher BMI probably has a lower baseline PSA level than someone with a normal range or low BMI.
Can PSA Levels Fluctuate?
PSA levels can fluctuate for a variety of reasons, including age, medical conditions, lifestyle factors, and medications. PSA levels are known to increase as we get older. The average PSA level for young men is around <1.0 ng/mL, while levels are expected to be at or below 4.0 ng/mL in men over 60. Generally, increased physical pressure on the prostate is thought to increase PSA levels. Thus, activities like cycling may cause higher levels7. PSA levels naturally fluctuate throughout the day. This is known as diurnal variation8.
Can a PSA Test Be Wrong?
PSA tests are not infallible and can sometimes produce inaccurate or misleading results. PSA tests can lead to false positives and false negatives. This means the test might indicate an issue when everything is actually normal or fails to detect a problem that is present. About 75 percent of elevated PSA tests are false positives for prostate cancer, meaning that no tumor is detected with biopsy despite the high PSA levels9.
What Can Skew a PSA Test?
In addition to natural variation in a man’s baseline PSA level, certain factors can temporarily skew a PSA test.
Here are six of the most common reasons for a rise or fall in PSA values:
1. Medications
Certain medications can cause a man’s PSA level to drop, including medications used to treat common concerns for aging men.
What Medications Can Increase PSA Levels?
Some steroid-based medications, such as testosterone and the anti-inflammatory drug betamethasone, may increase PSA levels10,11.
Drugs that can skew a PSA test include:
- NSAIDs: A class of pain medications that includes ibuprofen, Motrin, and Advil12
- Statins: A class of cholesterol-reducing drugs like Lipitor13
- Finasteride and Dutasteride: Medications used to treat an enlarged prostate, also called benign prostatic hyperplasia (BPH), and its symptoms14
- Blood pressure medication: Thiazide diuretics may lower PSA levels11
- Erectile dysfunction medication: A study found that Tamsulosin reduces PSA levels, while Tadalafil (Cialis) did not significantly change PSA levels15,16
It’s important to let your healthcare provider know if you take or have started taking any of these medications before you get a PSA test.
What Supplements Can Increase PSA Levels?
Many studies have examined the potential effect of different nutritional supplements on PSA levels in men with prostate cancer or those in high-risk categories. However, these results are inconsistent17,18.
2. DRE
Digital rectal exams (DRE) are exams used to manually examine the prostate. These exams are a routine part of most men’s yearly medical visits, and they were long thought to temporarily increase PSA levels. This increase is quite minimal, but it is still good to be aware of9.
3. Ejaculation
Ejaculation can increase a PSA score by up to 0.8 ng/ml starting within 1 hour and resolving to baseline after around 48 hours19,20.
4. Infection
Infections like bacterial prostatitis and inflammation of the prostate can temporarily cause elevated PSA levels21.
PSA values tend to return to baseline six to eight weeks after antibiotic treatment and when symptoms have resolved. Until then, you may want to delay your PSA screening.
Can a Virus Raise PSA Levels?
Recent research has found that some viral infections can lead to increased PSA levels. For instance, COVID-19 infection was found to increase PSA levels in men with BPH22. These levels were significantly lower before and after the infection. Other studies found an increase in PSA in men with Herpesvirus 8 infection and infectious mononucleosis23,24.
Can a Flu Shot Affect PSA Levels?
There is no evidence to suggest that flu shots affect PSA levels. However, COVID vaccination has been reported to cause a slight increase25.
5. Acute Urinary Retention
Acute urinary retention is an inability to fully empty the bladder through urination. This can be caused by swelling, infection, or trauma, and can greatly skew a PSA test26. After being treated for acute urinary retention, hold off on PSA testing for at least two weeks.
6. Prostate Biopsy
Prostate biopsies are a procedure in which a tissue sample is taken from the prostate. These are usually done when more information is needed to determine if someone has prostate cancer.
A biopsy can elevate PSA levels as few as four hours after the procedure, and the levels may remain elevated for up to four weeks. Avoid PSA testing for at least six weeks after a prostate biopsy27.
What Not To Do Before a PSA Blood Test
With these six tips in mind, here is a list of things to remember before going for a PSA blood test3,28.
Exercise - Though not mentioned above,exercise, especially lifting heavy weights or cycling, can increase PSA levels. Avoid these in the 48 hours preceding your test if possible.
Alcohol - Avoid alcohol before your test. It may reduce PSA temporarily.
Ejaculation - Avoid ejaculation in the 48 hours prior to your test.
Medications - Inform your healthcare provider of any medication you are taking before your test.
Illness - Inform your healthcare provider of any illnesses you have or have recently recovered from, as some of these may impact the test results.
DRE - Don’t get your PSA test shortly after a DRE.
Should I Test My PSA Levels?
Now that you know what can skew a PSA test and what can cause normal variations, let’s explore when you should test your PSA level.
The Centers for Disease Control and Prevention (CDC) recommends that men talk to their healthcare provider about the risks and benefits of PSA testing prior to making a decision29.
Men who are considered high-risk for prostate cancer should talk about PSA testing with their medical team when they turn 45 years old30. High-risk groups include:
- Men with a first-degree relative who had prostate cancer before turning 65 years old
- African-American men
Otherwise, men should have this conversation when they are 50 years old.
Deciding when to start checking a man’s PSA level is complicated due to the potential for false-positive test results.
When a PSA value is concerning, it may require invasive testing like a prostate biopsy to better understand the prostate’s health. But in the case of a false positive, this can cause unnecessary pain, infection, and the appearance of blood in semen.
Recommended reading: Know Your Prostate Cancer Risk: Calculator and Risk Factors
How Long Does It Take To Lower PSA Levels?
Elevated PSA levels can return to normal at different rates depending on the cause. For example, PSA typically normalizes about four weeks after a biopsy and within 48 hours after ejaculation. PSA levels may also decrease due to improvements in specific diseases or lifestyle changes, with the extent of reduction varying among individuals. Some people with high PSA levels do not have any health issues. Therefore, the question “How long does it take to lower PSA levels?” may not be relevant to your situation. You should talk to your healthcare provider about your PSA levels to determine the best action for your specific situation.
What is the Fastest Way To Lower Your PSA?
Elevated PSA levels occur for a variety of underlying reasons. Thus, there is no sure-fire way to reduce PSA levels. For instance, for an individual with prostate cancer, the fastest way to lower PSA may be to undergo radiation or surgery. Others may just need to wait while their PSA returns to normal levels after a biopsy31. Again, even if you have elevated PSA levels, it does not necessarily mean you have a health problem. Ultimately, individuals must discuss their PSA levels with their doctor to decide what course of action (if any) is required.
A Better Way To Screen for Prostate Cancer
A Better Way To Screen for Prostate Cancer
“Knowing what can skew a PSA test can help you interpret your PSA results more accurately. But a PSA test only shows part of your prostate health and can be influenced by many factors beyond cancer.”
A prostate MRI is a better way to understand your prostate health.
The Ezra Full Body MRI Scan screens for potential early cancer and early disease in the prostate and 12 other organs. It only takes an hour.
