At what haemoglobin level is a blood transfusion most beneficial?

A blood transfusion is most beneficial when the haemoglobin level is below 70 g/L. This threshold is based on clinical guidelines that indicate a haemoglobin level in this range represents a significant decrease in the oxygen-carrying capacity of the blood. Patients with such low haemoglobin levels are at higher risk for symptoms of anemia, such as fatigue, weakness, and increased heart strain due to inadequate oxygen supply to tissues.

Transfusing blood at haemoglobin levels below 70 g/L can effectively alleviate these symptoms, improve overall oxygen delivery within the body, and reduce the risk of complications associated with severe anemia. Most clinical practices endorse this threshold as a criterion for when to consider transfusion, focusing on patient safety and optimizing physiological function.

In contrast, higher levels of haemoglobin, such as above 100 g/L or above 120 g/L, typically indicate adequate oxygenation, meaning that blood transfusions may not be necessary or beneficial in those cases, as they would not provide significant improvement in the patient’s condition. The range between 70 g/L and 100 g/L does see transfusions used occasionally, but only based on specific clinical scenarios or patient needs, rather than as a standard practice.