Laboratory Medicine
Test Directory / Prostate Specific Antigen
Prostate Specific Antigen
Brown clotted serum, gel barrier
| Test | Prostate Specific Antigen |
|---|---|
| Common Abbreviations | PSA |
| Profile | NA |
| Tube type | Brown clotted serum, gel barrier |
| Clinical Indication | Measurement of serum PSA in conjunction with Digital Rectal Exam (DRE) is used as an aid in the detection of prostate cancer in men. PSA can also be used to determine the prognosis in patients with prostate cancer and for surveillance and monitoring treatment following diagnosis. After radical prostatectomy PSA levels routinely fall to the undetectable range. If prostatic tissue remains after surgery or metastasis has occurred, PSA is useful in detecting residual and early recurrence of tumour. Serial PSA levels can help determine the success of prostatectomy and the need for further treatment. Benign conditions that can cause elevated PSA levels include benign prostatic hypertrophy, acute and chronic prostatitis, UTI and urinary retention. A number of urological manipulations such as TURP, prostate biopsy, prostate massage and ejaculation may give rise to transient elevated levels. |
| Specimen Type | Blood |
| Sample type | Serum |
| Minimum Volume | 0.5mL If requesting more than 10 tests please send an additional brown clotted serum sample. |
| Special Precautions | No special requirements |
| Stability | 24 hours at 20 - 25°C, 3 days at 2 - 8°C and 24 weeks at -20°C |
| Turnaround Time | Inpatient: 24 hours Outpatient/ GP: 24 hours |
| Laboratory | York and Scarborough |
| Reference Interval | NICE cut off points used as the reference limits: 40-49 years: < 2.0 ng/mL 50-59 years: < 3.0 ng/mL. 60-69 years: < 4.0 ng/mL. Age 70+: < 5.0 ng/mL |
| Limitations | Analysis should not be performed on haemolysed, icteric or lipaemic samples. The assay is unaffected by biotin (< 4912 nmol/L or < 1200 ng/mL) No interference was observed from rheumatoid factors up to a concentration of 1500 IU/mL. In vitro tests were performed on 16 commonly used pharmaceuticals. No interference with the assay was found. In addition, special cancer drugs were tested. No interference was found. In rare cases, high titres of antibodies to analyte specific antibodies, streptavidin or ruthenium can occur. Effects minimised by assay design |
| Notes |
