1. What is PSA Doubling Time?

Definition: PSA doubling time is the time it takes for prostate-specific antigen (PSA) levels in the blood to double.

Purpose: It's an important marker in prostate cancer monitoring, with shorter doubling times often indicating more aggressive disease.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( T_d \) — PSA doubling time (days)
• \( t \) — Time interval between measurements (days)
• \( PSA_2 \) — Final PSA level (ng/mL)
• \( PSA_1 \) — Initial PSA level (ng/mL)

Explanation: The formula calculates how quickly PSA is rising by determining the time needed for a doubling at the current rate of increase.

3. Importance of PSA Doubling Time

Details: PSA doubling time helps clinicians assess prostate cancer progression and make treatment decisions. Generally:

• <3 months: High-risk feature
• 3-12 months: Intermediate risk
• >12 months: Lower risk

4. Using the Calculator

Tips: Enter the time between PSA tests (in days) and both PSA values. All values must be positive numbers, and PSA₂ must be different from PSA₁.

5. Frequently Asked Questions (FAQ)

Q1: What if my PSA decreased?
A: The calculator will show a negative value, indicating PSA is decreasing rather than doubling.

Q2: How many PSA measurements are needed?
A: While two points give a doubling time, more measurements provide a more reliable trend.

Q3: What's considered a normal PSA level?
A: Typically <4 ng/mL, but varies by age and other factors. Consult your doctor.

Q4: Does this replace medical advice?
A: No, this is for informational purposes only. Always consult a healthcare professional.

Q5: How accurate is PSA doubling time?
A: It's most reliable when using the same lab and assay method for consistency.