How low does your Hb need to be before they do a blood transfusion?

The decision to transfuse blood is based on a number of factors, including the patient's overall health, the cause of the anaemia, and the severity of the symptoms. There is no one specific Hb level that triggers a blood transfusion. In general, however, a transfusion may be considered if the Hb level drops below 7-8 g/dL (70-80 g/L) in adults. In some cases, a transfusion may be given at a higher Hb level if the patient is symptomatic or if there is a concern that the anaemia is causing organ damage.

Children and pregnant women may require blood transfusions at higher Hb levels due to their increased oxygen demands. Additionally, patients with certain medical conditions, such as heart disease or lung disease, may also require transfusions at higher Hb levels.

The decision to transfuse blood is a complex one and should be made on a case-by-case basis by a qualified healthcare professional.