Question

An unconscious patient is rushed into the emergency room and needs a fast blood transfusion. Because there is no time to check her medical history or determine her blood type, which type of blood should you, as her doctor, give her? A. A- B. AB + C. O+ D. O-

Short answer

D. O-

Step-by-step solution

Understand Blood Types and Transfusion Compatibility

Blood transfusions need to be compatible with the recipient’s blood type. An incorrect match can cause an adverse reaction. Blood types include A, B, AB, and O, and each type can be positive (+) or negative (-) based on the Rh factor.

Determine the Universal Donor Type

The universal donor blood type is O negative (O-) because it lacks A, B, and Rh antigens on the surface of the red blood cells, thereby minimizing the risk of an immune reaction regardless of the recipient's blood type.

Evaluate the Given Options

Review the blood type options provided: A-, AB+, O+, and O-. Since O- is the universal donor, it can be safely given to any patient in an emergency situation without prior blood type testing.

Key concepts

universal donor

When it comes to blood transfusions, compatibility is crucial. Some patients require an immediate transfusion, but there isn't always time to determine their exact blood type. In these urgent cases, we rely on the universal donor blood type, O negative (O-). O- blood lacks A, B, and Rh antigens on the surface of red blood cells. This means it is less likely to cause an immune reaction in any recipient. Generally, hospitals and emergency rooms keep a supply of O- blood for emergencies. This allows doctors to administer it quickly and safely until the patient's specific blood type can be identified.

Rh factor

The Rh factor is an important part of blood type compatibility. It refers to the presence or absence of a specific protein on the surface of red blood cells. If your blood has this protein, you are Rh positive (+). If it lacks this protein, you are Rh negative (-). The Rh factor can significantly affect transfusion compatibility. For example, if an Rh-negative person receives Rh-positive blood, their immune system may react negatively. Because of this, O- blood, which is Rh-negative, is often used in emergencies. It minimizes the risk of any Rh-related complications.

blood types

Blood types are divided into four main categories: A, B, AB, and O. These categories are determined by the presence or absence of specific antigens on the surface of red blood cells.

A person with type A blood has A antigens. Type B has B antigens. AB blood has both A and B antigens. Type O blood, on the other hand, has neither A nor B antigens. This makes type O the universal donor for the antigen categories because it doesn't have these markers that can trigger an immune response.

Each blood type can be either positive or negative, depending on the Rh factor. This results in eight possible blood types: A+, A-, B+, B-, AB+, AB-, O+, and O-. When matching blood for transfusions, both the ABO type and Rh factor must be compatible to ensure patient safety. Understanding these basics helps explain why O- blood is crucial in emergency transfusions.