TUESDAY, March 27 (HealthDay News) -- Aiming to cut back on unnecessary red blood cell transfusions, the American Association of Blood Banks has issued new recommendations that raise the bar for when patients should be considered in need of fresh blood.

The guidelines seek to clarify the level at which a patient's red blood cell count can be viewed as dangerously low, thereby triggering a transfusion.

An individual's red blood cell count level or "hemoglobin threshold" is deemed "healthy" when registering between 12 to 14 grams per deciliter. That hasn't changed.

However, until now physicians would sometimes view patients with a hemoglobin threshold of 9 or 10 as being anemic enough to require a transfusion.

But after an extensive review of the latest research, the association decided that such a "liberal" transfusion policy offered no additional protective health benefit to patients, and that most would do just as well if the threshold for transfusions was restricted to a lower level of 7 or 8 grams per deciliter in hospitalized, stable patients.

"We evaluated the medical evidence as to what patients are benefiting from more or less blood, and in what kind of circumstances and in what kinds of patients," said Dr. Jeffrey Carson, chairman of the recommendations committee. "And the evidence said that we can use less blood in certain settings: patients who are in the intensive care unit, patients who undergo most forms of surgery and even in patients who have preexisting heart problems."

Carson also serves as chief of the division of general internal medicine at University of Medicine & Dentistry of New Jersey-Robert Wood Johnson Medical School. The new guidelines appear online March 27 in the Annals of Internal Medicine.

Currently, red blood cell transfusion can become necessary when levels of hemoglobin -- which carries oxygen and is the principal ingredient in red blood cells -- drop below optimal levels of 12 to 14 grams per deciliter. This can happen, for example, as a result of blood loss in surgery.

At issue is the need to balance the potential benefits of transfusions against the potential risks. The association said that while transfusions can prolong a patient's lifespan, increase mobility and shorten hospital stays, there remains a relatively low but nonetheless present risk for infection, for "overloading" the patient with blood, and for allergic reactions or lung injuries.

"So the difference today," Carson added, "is that now we really have accumulated enough high quality evidence that we can be more definitive about what is best to do."

The expert panel analyzed research published between 1950 and 2011. The team stacked up red cell transfusion cases, the hemoglobin thresholds followed, and the amount of blood used in such transfusions against a range of related medical issues, including death, heart attacks, strokes, kidney failure, infection, bleeding, mental confusion, recovery time and hospital stay.

The result: Patients who underwent transfusions at higher hemoglobin levels of 9 or 10 grams per deciliter fared no better than those who underwent them at more restrictive levels of 7 or 8.

Though physicians are encouraged to judge on a case-by-case basis and also consider symptoms of anemia, the recommendations encourage doctors to only consider a transfusion at a hemoglobin level of 7 grams per deciliter for intensive care patients and at 8 for most other patients.

Dr. Darrell Triulzi, president of the blood bank association, suggested that the goal has been to find the sweet spot for patient care and public health.

"With transfusions, the risk that we used to be really concerned about was HIV and hepatitis infection," he noted. "But today that risk is very low. Less than one in a million. However, noninfectious risks of transfusion are far more common. Probably 10 to 100 times more common than any viral transfusion risk. So there's still good reason to not expose a patient to the risks of a transfusion without any evidence that they will benefit from it."

"And if anything," Triulzi said, "the research indicates that some patients might actually fare better without undergoing a transfusion, depending on their circumstance. And at the very least we know with certainty that at these lower thresholds they won't do worse."

At least one expert believes the new guidelines focus too little on the individual patient. Dr. Jean-Louis Vincent, professor of intensive care at Erasme Hospital Free University of Brussels, wrote in an accompanying journal editorial that basing the decision to transfuse on hemoglobin levels alone is insufficient.

"Transfusion decisions need to consider individual patient characteristics, including age and the presence of [coronary artery disease] to estimate a specific patient's likelihood of benefit from transfusion," Vincent wrote. "The decision to transfuse is too complex and important to be based guided by a single number."

More information

For more on blood transfusions, visit the U.S. National Heart, Lung, and Blood Institute.