PSA Standardization
PSA Sensitivity and Specificity
October 2009
The well known total PSA cutoff of 4.0 ng/mL was first proposed in 1986 from a study conducted by the company Hybritech, who evaluated a small population of 472 men without a history of prostate cancer.
A further screening study performed at Washington University involved 6630 men aged 50-74 years, and led to the approval of PSA by the US Food and Drug Administration for prostate cancer screening. This study clearly demonstrated the efficacy of the 4.0 ng/mL cutoff, which at the time, was considered an aggressive stance. A cutoff of 10.0 ng/mL was used commonly for triggering prostate biopsies in the early 1990’s.
Consequently, 4.0 ng/mL became well recognized as “the” biopsy cutoff, even though it was well known that men could have cancer with PSA values less than 4.0 ng/mL, and that values greater than 4 produced a 6/2% false-positive rate and detected only 20% of cases.
PSA Sensitivity and Specificity |
Jump to section:
- Introduction
- Elevated PSA Result on Screening
- Reasons for Ordering PSA1
- PSA Screening in the News
- Recommendations for Screening
- Arguments for Screening for Prostate Cancer
- Recommendations for Not Screening
- Arguments Against Screening for Prostate Cancer
- PSA Sensitivity and Specificity
- High-Grade Prostate Cancer is Not Rare When PSA =4.0 ng/mL6
- Increase Specificity Using PSA Velocity8
- Optimizing Clinical Sensitivity and Specificity: Age/Ethnic Reference Intervals9,10
- Utilization of Free/Total PSA Ratio11
- Why Aren't PSA Results Interchangeable?
- Development of PSA Standards
- Development of PSA Standards
- Effect of Analytical Bias on Classification Based on Fixed Criteria
- Analytical Difference: Results per 1000 Patients Tested13
- Hybritech vs. WHO Standardized Assays12,14
- Analytical Differences15
- CAP Proficiency Testing
- WHO 96/670 Total PSA Preparations16
- WHO Calibration/Concordance at 3.1 ng/mL Cutoff5
- WHO Calibration/Concordance at 3.1 ng/mL Cutoff5
- WHO Calibration/Concordance at 4.0 ng/mL Cutoff5
- Clinical Differences in PSA Screening14
- The Clinical Difference
- Fixed Thresholds Produce Problems for Biopsy Recommendations
- Effect on "Watchful Waiting"
- Effect on "Watchful Waiting"
- Adding Biological Variability into the Mix
- Futures in Prostate Cancer Testing?
- PSA Testing at Mayo
- Conclusions
- References
- References
- Questions?


