When is blood test recommended for anaemia?

Anaemia means the blood is carrying less oxygen than the body needs, often because haemoglobin or red blood cells are low. Tiredness, breathlessness on exertion, headaches, paleness, dizziness, or a fast heartbeat can lead to testing, although these symptoms have other causes too. A clinician may use a full blood count to check haemoglobin and the size and number of blood cells. Further tests can look for iron, vitamin deficiency, inflammation, kidney problems, or blood loss. The result is interpreted alongside your symptoms and medical history.

Tell the clinician about heavy or prolonged periods, digestive symptoms, recent illness, dietary restrictions, pregnancy, long-term conditions, and medicines such as anti-inflammatory painkillers. Mention any previous anaemia and bring relevant results if available. Ask whether you need to fast; many blood counts do not require fasting, but other tests taken at the same visit may. Do not start iron or vitamin supplements before discussing the plan, because the cause still needs to be established and supplements can affect interpretation.

Seek urgent medical help for severe breathlessness at rest, chest pain, fainting, new confusion, a very fast or irregular heartbeat with weakness, or bleeding that will not stop. Black or bloody stools, vomiting blood, or rapidly worsening symptoms also need prompt assessment. Mild tiredness can wait for a planned appointment, but persistent symptoms should not be self-treated indefinitely without checking what is causing them.

Ask which blood tests are planned, whether you need preparation, when results will be reviewed, and what further assessment is needed if haemoglobin is low.