Key Takeaways:
- O-negative "universal donor" blood is in chronically short supply in the U.S., raising concerns for emergency care and patient safety.
- Because anesthesiologists administer up to 60% of blood transfusions, they play a key role in conserving this limited resource.
- Changes in transfusion practice, along with increased blood donation, will help preserve O-negative blood supplies, anesthesiologists say.
CHICAGO — As blood banks across the U.S. report dangerously low supplies of O-negative blood (red blood cells) — commonly called the "universal donor" — anesthesiologists are calling for increased donation and changes in how hospitals use the "universal donor" blood type, according to a new Innovation in Practice article published online in Anesthesiology Open , an official journal of the American Society of Anesthesiologists (ASA).
Type O-negative blood can be given to patients of any blood type, making it essential in emergencies when a patient's blood type is unknown. Yet only about 8% of White/Caucasian individuals have this rare blood type, and the rates in other racial/ethnic groups are even lower, underscoring the need to carefully preserve this limited resource.
"O-negative blood is critical when patients need immediate transfusions before their blood type can be confirmed, such as during trauma care or other life-threatening emergencies," said study lead author Brent R. Lee, M.D., MPH, FASA of North American Partners in Anesthesia. "Because anesthesiologists administer up to 60% of all blood transfusions in the United States, they play a key role in preserving and promoting responsible management of this scarce resource."
The chronically low supply of O-negative blood could be completely drained in situations with high blood demand, such as mass casualty events, compromising patient safety, according to Dr. Lee and his colleagues.
The U.S. is experiencing one of the more significant blood donation shortage periods in recent years due to severe winter weather and cancelled blood drives, according to the American Red Cross. The authors stress the need to strengthen public awareness about the importance of blood donation — particularly by those with O-negative and O-positive blood. From March 1 – 31, 2026, the Red Cross is urging people to donate to recover the blood supply by offering a $15 Amazon gift card to each donor for donations made through March.
Type O-negative blood is critical for emergency use in patients whose blood type is unknown because it lacks antigens that can cause potentially serious reactions in people with other blood types. This is particularly important for women with childbearing potential, since it prevents potential Rhesus factor D (RhD)-mismatches in the blood that could be harmful to babies in future pregnancies. RhD is the inherited protein found on the surface of red blood cells that determines if a person's blood type is positive or negative.
Despite its critical role in emergency care, demand for O-negative blood outpaces the supply. Several factors contribute to this imbalance, including overuse of O-negative blood in situations where other blood types could be used.
The authors outline several strategies to conserve O-negative blood supplies:
- Use more readily available O-positive blood units for all male patients, as well as for female patients without reproductive potential (typically those aged 50 years or older) when blood type is unknown.
- Implement established blood-conservation techniques in high-risk bleeding scenarios such as cell salvage, point-of-care viscoelastic testing and administration of pharmacologic hemostatic agents (e.g., tranexamic acid).
Along with ASA, Dr. Lee and colleagues support the "Empower Group O Care" initiative of the American Red Cross — emphasizing the need to "Start Smart and Switch Sooner" when performing transfusions to patients of unknown blood type. Key recommendations include:
- Start emergency transfusions with O-positive blood in males and female patients beyond childbearing potential when blood type is unknown.
- Perform blood typing and crossmatching as early as possible to minimize the use of O-negative blood units.
- Reduce the inappropriate use of O-negative blood, particularly after the patient's blood type has been determined.
- Collaborate with blood bank and other hospital stakeholders to prioritize switching to type-specific blood.
"In collaboration with other specialties and national organizations, anesthesiologists play a key role in alleviating chronic blood shortages and preserving the availability of O-negative blood for those who need it most," Dr. Lee said. "It is imperative that we maximize the benefits of blood transfusion, while strengthening the security of the nation's blood supply."
THE AMERICAN SOCIETY OF ANESTHESIOLOGISTS
Founded in 1905, the American Society of Anesthesiologists (ASA) is an educational, research and scientific society with more than 60,000 members organized to advance the medical practice of anesthesiology and secure its future. ASA is committed to ensuring anesthesiologists evaluate and supervise the medical care of all patients before, during, and after surgery. ASA members also lead the care of critically ill patients in intensive care units, as well as treat pain in both acute and chronic settings.
