What should you know about a low HGB blood test?

Haemoglobin carries oxygen in red blood cells. A low result can occur when the body lacks iron, folate, or vitamin B12, when blood is being lost, or when red cells are not produced effectively. Anaemia is a common clinical label for low haemoglobin, but its cause still needs identifying.

Heavy periods, bleeding from the digestive tract, pregnancy, long-term inflammation, kidney disease, and inherited blood conditions may be considered. Coeliac disease and Crohn's disease can reduce absorption of nutrients. Symptoms may include tiredness, breathlessness on exertion, dizziness, paleness, headache, or a fast heartbeat, although some people have no symptoms.

Book a clinician review to discuss the result and the rest of the full blood count. Mention bleeding, periods, diet, pregnancy, digestive symptoms, medicines, and previous results. The assessment may include iron stores, vitamin levels, kidney function, and tests for bleeding, depending on your history.

Take supplements only when advised, because treatment depends on the cause. Keep the follow-up appointment even if you feel well; gradual changes can be easy to overlook.

Seek emergency help for chest pain, severe difficulty breathing, fainting, confusion, or a very fast or irregular heartbeat with weakness. Contact a clinician promptly for black stools, blood in the stool or vomit, heavy unexpected bleeding, or rapidly worsening dizziness. Urgency depends on symptoms as well as the HGB result.

Ask how low the result is compared with your previous tests, which type of anaemia is being considered, and whether bleeding or nutrient absorption needs investigation. Ask when repeat blood testing is needed and which symptoms should bring forward your review.