Haemoglobin (Hb)

Understanding the marker

Haemoglobin carries oxygen inside red blood cells. Its concentration is a key part of the blood count and helps assess anaemia, also called a low blood count.

Hb is interpreted against the laboratory reference interval and together with the blood count, symptoms and medical history. A low result supports anaemia but does not identify its cause; a high result may require follow-up according to its magnitude and context.

What does high Haemoglobin (Hb) mean?

High haemoglobin is assessed with haematocrit, the red-cell count and fluid balance. The degree of elevation, previous results and symptoms help determine what investigation is needed.

What does low Haemoglobin (Hb) mean?

Haemoglobin below the appropriate threshold supports anaemia. The level, symptoms, red-cell size and relevant iron or vitamin tests help assess the cause and how promptly it needs attention.