PSA is an abbreviation for prostate specific antigen, a protein that is only produced by cells found in the prostate gland. Prostate specific antigen is normally found in the seminal fluid, the fluid produced by the testes that carries sperm. When high levels of PSA are found in the blood instead of seminal fluid, it can be an indication that something is wrong with the prostate, Johns Hopkins University explains. However, several factors can temporarily increase PSA levels, meaning that doctors must be very cautious in interpreting PSA test results.
Other Prostate Conditions
Several noncancerous prostate conditions can elevate PSA levels, such as infection, inflammation of the prostate and benign prostatic hyperplasia, according to the National Cancer Institute. Roughly half of all high PSA tests return a normal result when retested, according to Lab Tests Online. For this reason, doctors often repeat PSA tests six weeks to three months after a high test result.
Prostate Manipulation
Another test for prostate cancer is the digital rectal exam in which a doctors checks the size of the prostate by inserting a finger into the patient's rectum. This physical probing of the prostate may cause a temporary elevation of PSA levels, Lab Tests Online reports. Similarly, a prostate biopsy, which is the removal of a tiny piece of prostate tissue for further testing, can also result in a temporary spike in blood PSA levels. Removal of part of the prostate, also called resection, to treat prostate cancer or other conditions, will similarly cause a transient elevation of PSA test results.
Medications
Hormone therapy for treating prostate cancer artificially lowers PSA levels, the National Cancer Institute explains, meaning that PSA tests to monitor the course of prostate cancer should not be administered immediately after hormone therapy. Similarly, the drug finasteride, which is used to treat benign prostatic hyperplasia, can decrease PSA levels by up to 50 percent after six months of treatment, according to Johns Hopkins University. Medications used for chemotherapy, including methotrexate and cyclophosphamide, can have unpredictable effects on PSA levels, either raising or lowering levels, reports Lab Tests Online.
Additional Factors
Certain rigorous physical activities, such as riding a bicycle, can temporarily increase PSA levels, according to Lab Tests Online. In men older than 50, ejaculation can raise PSA levels for up to two days, reports Johns Hopkins University. Another confounding factor is that blood PSA levels tend to increase as men age, although at different rates in different men. Additionally, race may impact PSA levels, although doctors do not know exactly the extent to which race is a factor, the National Cancer Institute notes.
