On call: Measuring the PSA Is fasting necessary?

Q. I have always had my blood tests taken the first thing in the morning, before I've had breakfast. We've just moved to a new home and I'll have a long commute to the hospital, so I'd like to eat before I start out. My cholesterol has always been great, so my doctor said a light breakfast won't interfere with cholesterol tests. But he didn't know if eating would change my PSA result. What do you think?

A. At last — a PSA question with a simple, un-equivocal answer: Breakfast will not affect your PSA result, nor will lunch or dinner. In June 2005, doctors proved the point by measuring PSA levels three times over the course of a single day in 80 patients with an average age of 62 years. The samples were obtained before breakfast, after breakfast, and after lunch — and there were no changes in the PSA results.