What is psa test?

The prostate-specific antigen (PSA) test is a blood analysis used to help diagnose prostate cancer. It identifies the levels of this prostate protein in the blood, which can suggest the possible presence of the disease. It’s a supportive diagnostic tool, but not a definitive test. To accurately determine if a patient with an altered PSA test result has prostate cancer, a prostate biopsy is required.

The prostate is a glandular organ in the male reproductive system, located under the bladder. It produces a protein called prostate-specific antigen (PSA), which is found mainly in seminal fluid and, to a lesser extent, in the blood.

When the PSA level in the blood increases, the chances of having prostate cancer also rise. Generally, a measurement greater than 4 ng/mL is considered a possible indicator of this oncological condition, although it isn’t always the case. This alteration can be caused by other factors, such as:

• Benign prostatic hyperplasia
• Prostatitis
• Certain medications
• Being an older adult
• Urological procedures
• Hormone therapy
• Having ejaculated the day before the test

Types of PSA Tests

There are two main types of PSA tests:

• Total PSA: Identifies the complete level of PSA present in the blood.
• Free PSA: Measures the presence of PSA not attached to blood proteins. The result is the proportion of free-circulating PSA compared to the total PSA level.

When a total PSA result is greater than 4 ng/mL, a free PSA test is recommended to determine if a prostate biopsy is necessary to check for cancer. For a free PSA test, a level below 10% increases the possibility of having prostate cancer.

Prostate cancer typically develops slowly and doesn’t usually metastasize. It often doesn’t show clear signs for years and doesn’t cause problems. Many people live with prostate cancer and don’t know they have it.

Preparing for the Test

You should not have ejaculated within 24 hours before the test, as this can alter the results.

Limitations of the PSA Test

• It’s not possible to pinpoint the exact source of PSA alterations, as there can be various causes, not just prostate cancer.
• It doesn’t distinguish between a slow-growing, non-metastatic prostate cancer and one that progresses and spreads quickly. Therefore, you could receive oncological treatment for a cancer that wouldn’t cause serious health problems, and the side effects of treatment could include:
  • Erectile dysfunction
  • Urinary incontinence
  • Fecal incontinence

Our Clinical Laboratory offers an integrated service with a multidisciplinary group of health professionals who support clinical diagnosis. Our goal is to provide the tools that allow a doctor to gather information to study, prevent, diagnose, and give you the best treatment.

Related Centers and Departments:

Internal medicine
Radiology and Molecular Imaging
Clinical Laboratory

Fuentes:

• elsevier.es
• topdoctors.es
• radiologyinfo.org
• msdmanuals.com
• mayoclinic.org
• medlineplus.gov
• medigraphic.com
• Sánchez-Lastra KY, García-Cortéz ÁE, González-Ávalos RM, et al. Incidencia y agresividad del cáncer de próstata por antígeno prostático específico y tacto rectal en el Hospital Regional “Lic. Adolfo López Mateos”. Rev Mex Urol. 2021;81(5):.
• Pérez L, García-Perdomo HA. Detección de antígeno prostático específico (PSA) para el cáncer de próstata (CaP): recomendaciones principales. Rev Mex Urol. 2021;81(2):1-7.
• Reyes-Sánchez EA, Reyes AJE, Rodríguez SY, et al. Detección de cáncer de próstata incidental con resección transuretral de próstata en pacientes con síntomas de tracto urinario inferior y antígeno prostático específico elevado del Hospital General de México. Rev Mex Urol. 2019;79(4):1-9.
• Sagué LJL, Proaño LS, Doimeadiós RZ. Papel del antígeno prostático específico en el cribado masivo o individual. Correo Científico Médico. 2019;23(1):210-221.