Haemoglobin
Amount iron carried by red blood cells. Lack of haemoglobin is called anaemia.

Heparin
Anti coagulant given to prevent the blood clotting, given as prophylaxis to prevent veno-occlusive disease.

Hickman line
Long term catheter, which is inserted into a large vein to facilitate administration of treatment.

Hodgkins Disease
Disease involving the lymph glands