PSA is a single chain glycoprotein normally found in the cytoplasm of the epithelial cells lining the acini and ducts of the prostate gland. PSA is a neutral serine protease of 240 amino acids involved in the lysis of seminal coagulum.
PSA is detected in the serum of males with normal, benign hypertrophic and malignant prostate tissue. The fact that PSA is unique to prostate tissue makes it a suitable marker for monitoring men with cancer of the prostate. PSA is also useful for determining possible recurrence after therapy when used in conjunction with other diagnostic indices.
Measurement of serum PSA levels is not recommended as a screening procedure for the diagnosis of cancer because elevated levels are also observed in patients with benign prostatic hypertrophy. After radical prostatectomy PSA levels routinely fall to the undetectable range. If prostatic tissue remains after surgery or metastasis occurs PSA appears to be useful in detecting residual and early recurrence of tumor. Therefore, serial PSA levels can help determine the success of prostatectomy and the need for further treatment such as radiation, endocrine or chemotherapy and in the monitoring of the effectiveness of therapy.
< 40 years old: Less than 1.3 ug/L
40 – 50 years old: Less than 2.0ug/L
50 – 60 years old: Less than 3.0 ug/L
60 – 70 years old: Less than 4.0 ug/L
> 70 years old: Less than 4.5 ug/L
Three patient identifiers from:
- Date of birth
- NHS number
- Unit number
should match on the specimen and request form. This check may be performed prior to centrifugation by the Central Sort department.