Is it necessary to be fasting when you have labs drawn? The dogmatic answer has long been yes, creating an uncomfortable, inconvenient situation for patients. They either have to return to the clinic a second time for labs or else uncomfortably fast until their doctor’s appointment. But a recent study published in JAMA Internal Medicine suggests that fasting likely isn’t necessary after all.
The study’s author looked at 3 meta-analyses (or collection of studies) and found the following:
-There wasn’t a significant difference in the cholesterol levels whether people fasted or not.
-Fasting and non-fasting lipid levels had the same predictive power for whether people would have an adverse cardiac event such as a heart attack.
For these reasons, clinical practice guidelines have changed to endorse non-fasting labs in most circumstances. The main situation when a person needs to do a fasting test is when the level of triglycerides (a type of bad cholesterol) is above 400. In this unusual circumstance, the lab should be repeated on a fasting basis.
This study’s conclusion, that people don’t need to usually fast for their labs, fits my practice. It’s news many patients will be glad to hear.
The study’s conclusions are linked here: