Serum prostate-specific antigen: hourly change/24 hours compared with prostatic acid phosphatase

Area of Science:

• Urology
• Biochemistry
• Clinical Chemistry

Background:

• Prostate-specific antigen (PSA) and prostate-advising phosphatase (PAP) are biomarkers used in prostate health assessment.
• Understanding the normal physiological variations of PSA and PAP is crucial for accurate interpretation of diagnostic levels.

Purpose of the Study:

• To investigate simultaneous hourly changes in serum PSA and PAP levels over a 24-hour period in individuals without prostatic disease.
• To determine if PSA or PAP levels exhibit diurnal variations.

Main Methods:

• Serum samples were collected hourly over 24 hours from 19 urologic patients without prostatic disease.
• Serum PSA levels were measured using Hybritech PSA-R Kits.
• Serum PAP levels were measured using an enzyme immunoassay (EIA) method.

Main Results:

• Serum PSA levels showed minimal variation and no significant diurnal pattern in 84% of patients, with a mean of 0.907 ng/mL.
• Serum PAP levels demonstrated diurnal variations in 5 patients, independent of PSA levels.
• Marked PSA variations occurred in 3 older patients, coinciding with PAP diurnal changes or constant high PAP levels.
• PSA levels did not significantly increase after prostatic massage and returned to baseline within 24 hours in most cases.

Conclusions:

• Serum PSA is a stable biomarker with no significant diurnal variation in men without prostate disease.
• Serum PAP levels exhibit diurnal variations, independent of PSA, suggesting different regulatory mechanisms.
• The findings are important for establishing appropriate cut-off levels for PSA and understanding its behavior post-prostate manipulation.