The Prostate-Specific Antigen (PSA) test is a common blood screening tool used to assess prostate health, particularly in older men. The result, a single number, is never interpreted in isolation; it must be viewed within the broader context of a man’s age, overall health, and medical history. For a 73-year-old man, determining a “normal” PSA level involves understanding a range that reflects the natural biological changes of an aging prostate, not finding one strict cut-off value. The test serves as an indicator that may signal the need for further evaluation, not a definitive diagnosis on its own.
Understanding the Prostate-Specific Antigen
Prostate-Specific Antigen is a protein produced almost exclusively by the cells within the prostate gland, both normal and cancerous. Its primary biological function is to help liquefy semen following ejaculation. While most PSA remains in the seminal fluid, a small amount naturally “leaks” into the bloodstream.
The PSA test measures the concentration of this protein found circulating in the blood, with results expressed in nanograms per milliliter (ng/mL). Since PSA is a normal product of the prostate gland, it is expected for a man to have a measurable level in his blood. An elevated result simply indicates that more of this protein is entering the bloodstream than usual, which can occur for various reasons.
Expected PSA Ranges for a 73-Year-Old Man
The concept of a normal PSA level changes significantly as a man ages, making the single universal threshold of 4.0 ng/mL outdated. Medical guidelines often use age-specific reference ranges to account for the natural growth of the prostate over time. These ranges help improve the specificity of the test, particularly in older individuals.
For a man in his 70s, the commonly cited age-adjusted upper limit for the PSA level is often up to 6.5 ng/mL. Some guidelines may suggest an upper limit as high as 5.0 ng/mL for the 70-79 age group, with levels up to 7.0 ng/mL potentially being considered acceptable under close observation. The reason the acceptable range increases with age is directly related to the prostate gland’s tendency to grow larger throughout a man’s life.
A larger prostate gland contains more cells, producing a greater total amount of PSA, which leads to a higher baseline level in the blood even when no cancer is present. This age-related increase in tissue volume means that a PSA level of 5.5 ng/mL, which might concern a 55-year-old, is frequently considered an expected finding in a healthy 73-year-old. These numerical guidelines are not absolute cutoffs, but rather serve as reference points for doctors to decide whether further testing is warranted.
Non-Malignant Causes of Elevated PSA Levels
An elevated PSA reading, even one above the expected range for a 73-year-old, does not automatically signify prostate cancer. Several common, non-cancerous factors can cause a temporary or chronic increase in the protein’s presence in the bloodstream.
One of the most frequent causes is Benign Prostatic Hyperplasia (BPH), a non-cancerous enlargement of the prostate that affects most men as they age. As the gland grows, its cells produce more PSA, which then diffuses into the blood, resulting in a chronically higher baseline level. Prostatitis, which is inflammation or infection of the prostate gland, is another significant cause, capable of causing a sharp, temporary spike in PSA levels.
Certain recent activities or medical procedures can also manipulate the prostate, causing a transient elevation. Ejaculation within 24 to 48 hours before the blood draw can cause a slight, temporary rise in PSA. Physical activities that put pressure on the perineum, such as vigorous cycling, have also been shown to increase PSA levels. Additionally, a Digital Rectal Examination (DRE) performed immediately before the blood test, or instrumentation like catheterization, can temporarily raise the PSA reading due to physical manipulation.
Interpreting Results and Subsequent Steps
If a 73-year-old man’s total PSA level is elevated, the initial step often involves confirming the result with a second blood test, ideally after eliminating non-malignant factors like recent ejaculation or infection. A doctor will then assess the patient’s risk by considering metrics beyond the single total PSA number.
One important metric is the PSA velocity, which measures the rate of change in the PSA level over time, typically over an 18 to 24-month period. A rapid increase, such as a rise greater than 0.75 ng/mL per year, may be more concerning than a consistently high but stable number. Another valuable tool is the free-to-total PSA ratio, which compares the amount of unattached PSA to the total amount in the blood. A lower percentage of free PSA (often below 10-25%) suggests that the elevation is more likely due to cancer, while a higher percentage points toward a benign condition like BPH.
If these additional metrics remain suspicious, a physician may recommend advanced imaging, such as a prostate MRI, to identify any suspicious lesions. A prostate biopsy, often guided by MRI results, remains the only definitive method to diagnose the presence of prostate cancer.