By Dr. Brian McDonough, Medical Editor

PHILADELPHIA (CBS) – According to new guidelines being published in the Annals of Internal Medicine, the American Association of Blood Banks recommends physicians consider transfusing at a hemoglobin threshold of 7 to 8 g/dl.

READ MORE: 14-Year-Old Boy Shot Nearly 20 Times, Killed While Waiting For SEPTA Bus In North Philadelphia, Police Say

Those numbers are not as important as the fact that there are recommended guidelines and they are not liberal. They want physicians to be more careful about blood transfusions.

READ MORE: Police Investigating 'Suspicious' Deaths Of 2 Men Found In Box Truck In Northeast Philadelphia

A 20-member panel of experts looked at data from 1950 to 2011 to see what works best and avoid unnecessary transfusions.

MORE NEWS: Crash Involving Tractor-Trailer, SUV Closes Route 130 North In Burlington County

The researchers examined things like overall mortality, non-fatal myocardial infarction, cardiac events, pulmonary edema, stroke, blood clots, kidney failure and many more areas. This is a great example of what we call evidence-based medicine, where decisions are made based on looking at large amounts of data.