It’s one of those basic, unquestioned rules of medicine: don’t eat anything for 8 to 12 hours before having a cholesterol test. But does having a blood test on an empty stomach make that big a difference?
And is it really the best way to see how much fat is really in your bloodstream on a day-to-day basis?
A new study in the journal Circulation (from the American Heart Association) says maybe the best time to poke that needle for a blood test is anytime.
Researchers followed more than 16,000 people over a 14 year period and found that there was little difference in accuracy of the tests and whether the patients actually lived longer (and healthier) based on fasting versus non-fasting blood testing.
In other words, it made no practical difference if someone starved for 12 hours or stopped for a burger and fries on the way to the doctor’s office before a blood test.
When you think about it, it may make sense to get a real time snapshot of what’s circulating in your blood. Most of us don’t fast for 12 hours during the course of a day or night, so having a blood test done under artificial circumstances may not really show how much fat is ordinarily running through your pipes. And that’s really what you want to know.
Seriously, I’d like to see what your blood fat levels are like on a real day in your life — one where you’ve maybe had a bag of chips — rather than measuring on an “artificial day” where you are on your best behavior.
Plus, think of the convenience. Typically the cholesterol (or lipid profile, as we call it) is a three step process.
You come in to see me. I say, “I think you need a cholesterol test. Come back on another morning after you’ve fasted.”
You return on another day, starving, with your sleeve rolled up.
Then after the results are back, I need to bring you back to the office, or call you, to explain the results — tell you what to if its elevated — plus talk to you about medication if it’s really elevated.
So maybe nailing you on the spot takes one of those steps away. But even that one step can be a nice thing to bail on and make you more likely to be tested.
Odds are your doctor may not buy into the idea of the non-fasting test. It’s not really in vogue, plus we miss out checking your blood glucose for diabetes by letting you eat.
Nonetheless, if it means we can get an idea of where you are blood fat-wise by checking it on the spot … that’s certainly better than hoping you’ll come back some inconvenient morning during your busy life.