Physician Frequently Asked Questions

Understanding the ExoDx Prostate Test for risk assessment of High Grade Prostate Cancer

The ExoDx Prostate Test came back at “Higher Risk” but a biopsy result came back negative. How should I interpret this result?

The purpose of the EPI test is to rule out patients who don’t need a biopsy. If a patient is below the 15.6 cut-point, the chance of finding HGPCa is < 11%


What is the Negative Predictive Value (NPV)?

Negative Predictive Value is a statistical measure that says how confident we are about a negative outcome. In the case of The EPI-CE Test, an NPV of 89% means we are 89% certain that the patient will not have HGPCa at a cut point of 15.6 or less.


What is the sensitivity of The EPI Test?

The sensitivity of The EPI Test is 92%. The sensitivity measures the proportion of actual GG2 (GS7) and above that are correctly identified as positive.


What is the cut-point used to determine high risk vs. lower risk?

The EPI Test has been validated using a cut point of 15.6 to determine when patients are at lower risk for high grade prostate cancer, defined as Gleason 7(3+4) / Grade Group 2 or higher. Patients with an EPI score below this cut point have a very low risk (11%) of not having high grade prostate cancer.


Does The EPI Test distinguish between GG1/GS6 and GG2/GS7 and higher prostate cancer?

Yes. The EPI Test is optimized as a rule out test to distinguish high grade prostate cancer (defined as GG2/GS7 and above) from low grade prostate cancer. Patients above the cut-point of 15.6 are associated with high risk of high grade prostate cancer. Patients below the cut-point of 15.6 are associated with lower risk of high grade prostate cancer.


Why do I need to use your collection cup?

The prostate biomarkers we are looking for have the highest concentration in the “First Catch” urine sample which is the first 15mLs of the void and is mostly from the prostate. Urine for isolation of exosomal RNA must be the first catch with a minimum volume of 10mL and a maximum of 50ml, derived from the intended use population. To maximize urine input consistency, Exosome Diagnostics recommends collection of urine in a dedicated, validated collection device such as the ColliPee Device (Novosanis, Cat # N00055.  Order a kit.


Which RNA biomarkers are analyzed?



What should I do if the patient voided 30 minutes ago?

Please have the patient wait at least one full hour since last void before providing a new sample. The ExoDx Prostate Test is most accurate when there is sufficient signal in the urine sample, which occurs with the First Catch.

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