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Haemoglobin

Anemia Biomarker

Sample Needed

Collection Type: Blood

Body System

Related System: Anemia

Overview

Haemoglobin is the oxygen-carrying protein inside red blood cells that binds oxygen in the lungs and delivers it to tissues. The haemoglobin test measures the concentration of this protein in whole blood and is a key marker of red cell mass and oxygen-carrying capacity. It is used to detect and monitor anaemia (low haemoglobin) and polycythaemia (high haemoglobin). Symptoms that commonly prompt testing include fatigue, pallor, shortness of breath, rapid heartbeat, dizziness, or unexplained weakness. Normal haemoglobin varies by age, sex, pregnancy status, altitude, and smoking: males typically have higher values than females, pregnant women have physiologically lower concentrations, and infants/children have different age-specific norms.

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Test Preparation

No special preparation is required

Why Do I Need This Test

Profile: Included in the Anemia profile.
Symptoms prompting the test: fatigue, pallor, breathlessness, tachycardia, lightheadedness, or suspected bleeding.
Conditions diagnosed/monitored: iron‑deficiency anaemia, vitamin B12/folate deficiency, haemolytic anaemia, chronic disease anaemia, acute blood loss, and polycythaemia.
Reasons for abnormal levels: blood loss, nutrient deficiencies, bone marrow disease, chronic inflammation, dehydration, living at high altitude, smoking, or inherited haemoglobin disorders.
Family history of thalassemia or sickle cell disease increases the need for testing.

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Understanding Test Results

Values below the sex-specific cutoffs indicate anaemia: haemoglobin <13.0 g/dL in men and <12.0 g/dL in non-pregnant women is diagnostic for anaemia.
Severity categories commonly used: mild ~10.0–12.9 g/dL (men) or 10.0–11.9 g/dL (women); moderate 8.0–9.9 g/dL; severe <8.0 g/dL lower levels raise concern for significant functional impairment and need urgent evaluation.
Low Hb suggests iron deficiency, chronic disease, haemolysis, bone marrow disorders, or acute blood loss; rapid falls indicate active bleeding or haemolysis.
Elevated values above typical upper limits (e.g., >17 g/dL in men, >15 g/dL in women) suggest relative hemoconcentration (dehydration), chronic hypoxia, smoking-related erythrocytosis, or primary polycythaemia (polycythaemia vera); very high levels (>20 g/dL) increase risk of hyperviscosity and thrombotic events and require prompt assessment.
Interpretation should be combined with red cell indices, reticulocyte count and clinical context.

Normal Range

Men: 13.8-17.2 g/dL OR 138-172 g/L Women (non-pregnant): 12.1-15.1 g/dL OR 121-151 g/L Pregnant women: ≥11.0 g/dL OR ≥110 g/L (lower reference) Children: age-dependent; typical range ~11.0-16.0 g/dL OR 110-160 g/L

FAQs

Q: What is a normal level of hemoglobin?

A: Normal hemoglobin varies by age, sex and pregnancy. Typical adult male: about 13.8–17.2 g/dL; adult female: about 12.1–15.1 g/dL. Pregnant women are often considered normal at ≥11.0 g/dL. Children’s normal values depend on age (roughly 11–16 g/dL across childhood with higher newborn values). Lab-specific ranges may differ, so discuss results with your healthcare provider.

Q: What happens if haemoglobin is low?

A: Low haemoglobin (anaemia) reduces blood’s oxygen-carrying capacity, causing fatigue, weakness, shortness of breath, dizziness, pale skin, rapid heartbeat and chest discomfort. Cognitive function, exercise tolerance and immune response may worsen; severe or prolonged low haemoglobin can impair organ function, increase infection risk, and in extreme cases lead to heart failure. Causes and treatment vary and need medical evaluation.

Q: How can I raise my hemoglobin fast?

A: To raise hemoglobin quickly, eat iron-rich foods (red meat, liver, poultry, fish, lentils, beans, spinach) with vitamin C sources (oranges, bell peppers) to boost absorption; avoid tea/coffee at meals. Take prescribed oral iron supplements (or IV iron for severe deficiency) and correct B12/folate if low. Get blood tests and follow your doctor’s guidance to treat underlying causes.

Q: What is haemoglobin in blood?

A: Haemoglobin is an iron-containing protein in red blood cells that binds and transports oxygen from the lungs to tissues and carries some carbon dioxide back to the lungs. It gives blood its red colour and is essential for cellular respiration. Haemoglobin levels indicate oxygen-carrying capacity; low levels cause anaemia, while high levels may reflect dehydration or other conditions.

Q: What is a serious hemoglobin level?

A: Hemoglobin below about 7–8 g/dL in adults is typically considered severe and may require urgent treatment (often transfusion or hospital care). Levels under 7 g/dL commonly prompt transfusion consideration. Warning signs include chest pain, severe breathlessness, fainting, rapid heartbeat, confusion, or very low blood pressure. Anyone with these values or symptoms should seek immediate medical evaluation.

Q: How to treat low hemoglobin?

A: Treat low hemoglobin by identifying and addressing the cause with a healthcare provider. Common treatments include iron supplementation and dietary changes (iron-rich foods plus vitamin C), vitamin B12 or folate replacement when deficient, treating bleeding sources, and using erythropoiesis-stimulating agents for chronic disease. Severe cases may need blood transfusion. Regular blood tests monitor response and dosing.