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The appropriate lower limit for the percent free prostate-specific antigen reflex range
G D Carlson1, C B Calvanese, S J Childs
1DIANON Systems, Stratford, Connecticut 06615, USA.
Urology
|September 8, 1998
Summary
The study determined that a total prostate-specific antigen (PSA) level of 4.0 ng/mL is the lowest threshold where percent free PSA can effectively differentiate between benign and malignant prostate conditions, aiding in diagnosis.
Area of Science:
- Urology
- Oncology
- Biochemistry
Background:
- Percent free prostate-specific antigen (PSA) is crucial for differentiating benign from malignant prostate disease.
- Its utility is established above 4.0 ng/mL total PSA, but the lower limit remains unclear.
Purpose of the Study:
- To determine the lower limit for the percent free PSA reflex range.
- To define the threshold where percent free PSA reliably distinguishes between benign and malignant prostate conditions.
Main Methods:
- Analysis of 479 men with total PSA ≤ 4.0 ng/mL.
- Comparison of percent free PSA distributions in benign versus malignant cases using biopsy results.
- Statistical analysis including Mann-Whitney U test, ANOVA, and logistic regression.
Main Results:
- The lowest total PSA value where percent free PSA distributions differed between benign and malignant cases was 4.0 ng/mL.
- Percent free PSA at 4.0 ng/mL total PSA was found to predict malignant disease.
Conclusions:
- The established lower limit for the percent free PSA reflex range is 4.0 ng/mL.
- This threshold is critical for accurate prostate cancer diagnosis in men with lower PSA levels.
