The ratio of free to total PSA, which helps distinguish benign from malignant prostate disease.
The PSA free/total ratio is a calculated value, not a separate blood test. It divides free PSA by total PSA and is shown as a percentage.
It exists to add detail when total PSA is borderline. The ratio helps weigh whether a raised PSA is more likely from benign prostate enlargement or from something that needs a closer look.
This ratio is most useful when total PSA falls in the grey zone, often 4 to 10 µg/L, and the prostate exam is normal. A higher percentage of free PSA leans toward a benign cause such as BPH. A lower percentage raises the chance of prostate cancer.
The ratio is a probability tool, not a diagnosis. Your doctor uses it together with your age, PSA trend, and exam to decide whether further steps, such as imaging or biopsy, are worth considering.
Aniva reads your result against research-backed ranges, not just the lab's wide normal. The reference shown below is specific to this biomarker.
The ratio is given as a percentage. Ranges are guidance only and the exact cutoff depends on the assay.
| Free/total ratio | General interpretation |
|---|---|
| Higher (often above ~25%) | More likely benign |
| Lower (often below ~10 to 15%) | Higher chance of cancer, warrants review |
Used mainly when total PSA is 4 to 10 µg/L. Aligned to German laboratory practice (DGKL).
Because the ratio depends on both PSA measurements, anything that skews PSA, such as recent ejaculation, cycling, a prostate exam, infection, or 5-alpha-reductase drugs, can affect it. Delayed sample handling lowers free PSA and distorts the ratio. Different assays give different cutoffs.
Read together with total PSA, free PSA, and a clinical prostate exam.
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