Hemoglobin (HGB)
Blood count (CBC) ·Also called: HGB, Hb, haemoglobin, blood pigment
What it is
Haemoglobin is the pigment that makes blood red. Each red cell is packed with it, and each molecule can pick up oxygen in the lungs and release it in the tissues. The analyser measures the total amount present in the sample rather than counting cells.
Why your vet measures it
Two pets can have a similar red cell count but different haemoglobin, because the cells can be under-filled — most often when iron is short. Haemoglobin is therefore the truest single measure of oxygen delivery, and it moves in step with haematocrit in most healthy animals.
What a high result can mean
- Dehydration concentrating the blood
- Splenic contraction from stress or excitement at the clinic
- A sustained response to low blood oxygen in chronic heart or lung disease
What a low result can mean
- Anaemia of any cause — bleeding, destruction, or underproduction
- Iron deficiency, usually from slow chronic blood loss such as gastrointestinal bleeding or parasites
- Chronic kidney disease, which reduces the hormone signal that tells the marrow to make red cells
Dogs and cats differ
In cats, haemolysis of the sample during collection is a common source of a falsely raised reading, because feline red cells are fragile and feline blood draws are often slower. Your vet may repeat the test rather than act on a single odd value.
Questions worth asking your vet
- Does the haemoglobin match the red cell count and haematocrit, or is one out of step?
- Could the sample quality have affected this number?
- Should we check iron status if it is low?
Related terms
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