Fingerprick PSA Test: Clear Benefits, but Also a Few Concerns

Gerald Chodak, MD


May 06, 2019

This transcript has been edited for clarity.

Hello. I'm Dr Gerald Chodak for Medscape. Today's topic is on a new, office-based prostate-specific antigen (PSA) test called the Sangia Total PSA Test, which was recently approved by the US Food and Drug Administration (FDA). It only requires a fingerstick to obtain whole blood, and the results are available in about 15 minutes or less.

The studies that were done demonstrated that it was a reliable test, with a low coefficient of variation.[1] When compared with an approved, commercially available PSA test, the results were very similar.

The test uses a cut-off of 4 ng/mL, and in doing that, it has an 85% sensitivity and a positive predictive value of 60%. If it is combined with an abnormal digital rectal exam, the positive predictive value goes up to 70%. It appears to be a very useful test.

Also, if men have a Gleason score of 6 or less, then about 36% would have a falsely negative result. For men with a Gleason score of 7 or higher, only 18% will have a falsely negative result.

What does this mean for patients? Clearly, it has a potential benefit in that men can go in, see the doctor, get the result, and have a discussion right away about what that result means. For men who have had negative PSA tests and have had to wait several days to either get a phone call, or even worse, go back into the office, this will be much more convenient.

However, there is a potential that the test may not be used as appropriately as is desirable. Current guidelines recommend that patients and doctors have a discussion about the pros and cons of PSA testing before the test is done. In other words, shared decision making should take place.

Will the easy availability make that discussion even less likely to occur, even though it probably doesn't occur very often right now? Also, what about finances? We don't know yet how much is involved in acquiring the technology or how much space is needed in a doctor's office. Certainly, there will be ways that doctors could share a machine, share the results, and get this done.

Will it be a moneymaker in some way? Will there be a profit associated with it so that more tests are ordered, even in men who probably shouldn't have the test done anymore? Clearly, these are questions that need to be addressed as the technology is acquired and incorporated into clinical practice.

The bottom line, however, is that this is certainly going to offer many men a more convenient way to receive their PSA test.

I look forward to your comments. Thank you.


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