how do you calculate the fpsa/tpsa ratio?

Mel,   You’ve got the info you need, you just have the words jumbled up.   You are asking about the percent (or ratio) of free PSA in total PSA , and you already have your answer:   24%.   A standard PSA tests measures total PSA , but as you probably know, PSA can be high for both cancerous and non-cancerous causes…in other words, the PSA test is not very “specific” for prostate cancer.   We talked in a separate thread about how the PCA3 test can help determine whether someone with a moderately high PSA should go forward with a “uncomfortable” and costly biopsy.   The measure of free PSA percentage serves a similar purpose…to indicate whether a biopsy is warranted.   Total PSA is made up of two sub-types:   “free” and “bound” (or “complexed”) PSA .   PSA gets “bound” to proteins when PC is present.   Therefore, a low free PSA percentage suggests malignancy .   The percent free PSA is a refinement of the PSA test, but once again (like the PCA3 test) there is a wide “gray zone” which between the high and low results.   Dr William Catalona, who is recognized as the developer of the PSA screening test (and a practicing prostate surgeon in Chicago ) reported these stats: If the percentage of free PSA is higher than 25%, the likelihood of prostate cancer is about 8%. If the percentage of free PSA is less than 10%, then the likelihood of prostate cancer rises to 56%. At 24%, you are on the favorable side of the “gray zone", although I wish that your PCA3 result was better.   Keep in mind that both of these (PCA3 and % free PSA ) are simply indicators whether you should have a biopsy.   Someone does not definitively have PC until they get a biopsy result that says they do.   Good luck with your biopsy next week.