What blood type do you administer?

HCDFRS administers Low Titer Type O+ Whole Blood (LTO+WB). Here’s why:

  • Low Titer: Contains low levels of antibodies, making it safe to transfuse to a patient with any blood type.
  • Type O+: Type O blood is known as the universal donor, meaning it can be transfused to any patient. O+ blood is much more commonly available than O-. Only 7% of the U.S. population has O- blood type, compared to 37% who are O+. 
  • Whole Blood: Contains all blood components (red blood cells, plasma, and platelets) in one product.

LTO+WB is a U.S. Food and Drug Administration (FDA) and Association for the Advancement of Blood & Biotherapies (AABB) approved blood product for emergency release in life-threatening situations where blood is needed immediately and the patient's blood type is unknown. It is in use at the R Adams Cowley Shock Trauma Center, the Johns Hopkins Hospital Trauma Center, and more than 100 other trauma centers in the U.S.

What is the Whole Blood Program, and who is eligible?

The Whole Blood Program allows specially trained HCDFRS paramedics to administer whole blood transfusions to patients who have sustained significant blood loss through suspected traumatic injury and/or internal bleeding.

Prehospital whole blood may be administered to select patients over one year old with significant bleeding (traumatic, obstetric, gastrointestinal, etc.) and signs of hemorrhagic shock. To determine eligibility for the Whole Blood Program, HCDFRS clinicians follow Maryland Emergency Medical Services Clinician Protocols, issued annually by the Maryland Institute for Emergency Medical Services (MIEMSS). Whole blood is safe for administration to patients of all ages and blood types, including children and pregnant women.

Why do field blood transfusions matter?

The timely administration of whole blood to a patient with significant blood loss is an essential step in increasing survivability. In injuries with high volumes of blood loss, some of the best medicine we can provide to our patients is stopping the bleed and/or replacing the blood they’ve lost from their injury and getting them to the hospital.

A growing body of data shows better outcomes for patients who receive blood in the field, prior to arriving at the hospital. Evidence suggests early whole blood administration (less than 35 minutes from injury) in severely injured trauma patients can increase survivability.[i] EMS crews can get the blood on board sooner than waiting for that patient to arrive to the hospital, which improves outcomes.[ii]

A 2022 study in the Journal of American College of Surgeons determined that whole blood increased 30-day survival by 60% and reduced the need for 24-hour blood products by 7%.[iii] Prehospital whole blood is permitted by the AABB standards.[iv]

Are whole blood transfusions safe?

Whole blood transfusions have been utilized as far back as 1917. All whole blood that is administered is low in titer level of anti-A and anti-B antibodies, making it safer for administration and less likely for a transfusion reaction to occur. Prehospital administration of whole blood is being utilized safely in dozens of EMS systems throughout the country and nearly half of trauma centers. Adverse severe reactions are rare.

How is it made?

Blood is collected from volunteer donors, screened for disease, and verified to have non-significant levels (low titers) of antibodies against Type A or B blood. White blood cells are filtered out, but the blood is left whole, with plasma and platelets to promote clotting and red blood cells to carry oxygen.

Can patients refuse or opt out of the Whole Blood Program?

Conscious patients can refuse a blood transfusion at any time. For unconscious patients, providers will check for relevant medical identification, including alert tags, for any patient directives before issuing whole blood.

Is it safe to give Rh+ blood to patients who are Rh-?

Since the patients who are eligible for a whole blood transfusion are typically at risk of imminent death, the risk/benefit consideration falls in favor of RH- patients receiving RH+ blood.[v] The risk of complications is very low.

What about women of childbearing age who are Rh-?

Since the patients who are eligible for a whole blood transfusion are typically at risk of imminent death, the risk/benefit consideration falls in favor of a LTO+WB transfusion.

Is whole blood safe for children?


Does this interfere with the administration of other blood products or medication?


Can patients who receive LTO+WB get additional medication or blood products at the hospital?


What if patient has a transfusion reaction after being dropped off at the hospital?

Prehospital transfusion reactions are rare but are a possibility. EMS clinicians will treat any reactions accordingly, including the administration of emergency medications. The blood bank and the department will coordinate with the receiving hospital. In addition, the EMS crew will leave the blood tubing, which will be sent for testing.



[i]. Shackelford SA, Del Junco DJ, Powell-Dunford N, et al. Association of Prehospital Blood Product Transfusion During Medical Evacuation of Combat Casualties in Afghanistan With Acute and 30-Day Survival. JAMA. 2017;318(16):1581-1591.


[ii]. Braverman MA, Smith A, Pokorny D, et al. Prehospital whole blood reduces early mortality in patients with hemorrhagic shock. Transfusion. 2021;61 Suppl 1:S15-S21. doi:10.1111/trf.16528


[iii]. Brill JB, Tang B, Hatton G, Mueck KM, McCoy CC, Kao LS, Cotton BA. Impact of Incorporating Whole Blood into Hemorrhagic Shock Resuscitation: Analysis of 1,377 Consecutive Trauma Patients Receiving Emergency-Release Uncrossmatched Blood Products. J Am Coll Surg. 2022 Apr 1;234(4):408-418. doi: 10.1097/XCS.0000000000000086.


[iv]. http://www.strac.org/files/Prehospital/WholeBlood/LTOWB-press-release-from-THOR-8-Jan[23454].pdf


[v]. McCoy CC, Montgomery K, Cotton ME, Meyer DE, et al. Can RH+ whole blood be safely used as an alternative to RH- product? An analysis of efforts to improve the sustainability of a hospital's low titer group O whole blood program. J Trauma Acute Care Surg. 2021;91(4):627-633.


[vi]. Perea LL, Moore K, Hazelton JP. Whole blood resuscitation is safe in pediatric trauma patients: A multicenter study. The American Surgeon. February 13, 2023. [Epub ahead of print]. https://doi.org/10.1177/00031348231157864


[vii]. Morgan KM, Yazer MH, Triulzi DJ, Strotmeyer S, Gaines BA, Leeper CM. Safety profile of low- titer group O whole blood in pediatric patients with massive hemorrhage. Transfusion. 2021;61(Suppl 1):S8-S14

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