Blood Test

Hemoglobin (Hb) Test

Name: Hemoglobin Test: Normal Range & Low | HealthReview
Creator: Suman Konda
Published: 2026-07-05

Haemoglobin is the protein in red blood cells that carries oxygen to every cell in your body. A low result means anaemia; a high result can indicate dehydration or a blood disorder.¹

Written by Suman Konda, Clinical Pharmacist · Based on peer-reviewed sources · Editorial policy · Not medical advice

Last reviewed and updated: 26 September 2026 · How we check our content

Quick answer

Haemoglobin is the oxygen-carrying protein in red blood cells; normal is 13.5-17.5 g/dL in men, 12.0-15.5 in women, and 11.0 or above in pregnancy. Low haemoglobin is anaemia, most often from iron deficiency, and causes fatigue and breathlessness. High haemoglobin can reflect dehydration, smoking or lung disease. Below 8 g/dL needs urgent assessment.

What is haemoglobin?

Haemoglobin (Hb or Hgb) is the iron-containing protein inside red blood cells that binds to oxygen in the lungs and delivers it throughout the body. It also carries carbon dioxide back to the lungs. The haemoglobin test is part of a Complete Blood Count (CBC) and is the primary test for diagnosing anaemia.

Haemoglobin normal range

Group	Normal Range (g/dL)	Interpretation
Adult men	13.5 – 17.5	Normal
Adult women	12.0 – 15.5	Normal
Pregnant women	≥ 11.0	Acceptable in pregnancy²
Children (6-12 yrs)	11.5 – 15.5	Normal
Severe anaemia	< 8.0 (any adult)	Urgent assessment

Key points

Haemoglobin is the iron-containing protein inside red blood cells that carries oxygen; low haemoglobin is called anaemia.
Normal ranges: adult men 13.5-17.5 g/dL, adult women 12.0-15.5 g/dL, pregnant women 11.0 or above, children (6-12 years) 11.5-15.5 g/dL.
The commonest cause of anaemia worldwide is iron deficiency, from poor diet, blood loss (heavy periods, GI bleeding) or poor absorption.
Other causes include B12 or folate deficiency, chronic kidney disease, chronic inflammation, thalassaemia and haemolysis.
High haemoglobin can reflect dehydration, smoking, high-altitude living or chronic lung disease; very high levels thicken the blood and raise clot and stroke risk.
Mild anaemia may cause few symptoms; moderate causes fatigue and breathlessness on exertion, while severe anaemia (below 8 g/dL) needs urgent assessment.

LOW Haemoglobin: Anaemia

Low haemoglobin is called anaemia. The most common cause worldwide is iron deficiency due to poor diet, blood loss (heavy periods, GI bleeding) or poor absorption. Other causes: vitamin B12 or folate deficiency (megaloblastic anaemia), chronic kidney disease, chronic inflammatory conditions, thalassaemia and haemolytic anaemia. Symptoms include fatigue, weakness, pale skin, shortness of breath, dizziness and rapid heartbeat.

HIGH Haemoglobin: Polycythaemia

High haemoglobin (polycythaemia or erythrocytosis) causes include dehydration, high-altitude living, smoking, chronic lung disease (COPD) and polycythaemia vera (a bone marrow condition). Very high Hb thickens the blood and raises clot, stroke and heart attack risk.

Grades of anaemia

Severity	Hb (g/dL)	Typical symptoms
Mild	10 – 12 (women) / 10 – 13.5 (men)	Few or none
Moderate	8 – 9.9	Fatigue, breathlessness on exertion
Severe	< 8	Breathlessness at rest, chest pain
Critical	< 6.5	Emergency: may need transfusion

Questions to ask your doctor

What type of anaemia do I have?
Do I need iron, B12 or folate supplements?
Should I have ferritin and iron studies?
Do I need a colonoscopy to check for GI bleeding?
When should I retest?

Haemoglobin at a glance: the compiled numbers

Haemoglobin cutoffs differ by age, sex and pregnancy — here are the typical adult bands, compiled from this page's range tables:

Group	Typical range*	Unit
Adult men	13.5–17.5	g/dL
Adult women	12.0–15.5	g/dL
Pregnant women	11.0 and above considered acceptable	g/dL
Children (6–12 yrs)	11.5–15.5	g/dL
Severe anaemia (any adult)	Below 8.0 — urgent assessment	g/dL
Typical cost (as part of CBC)	&rupee;250–500	per CBC panel

*Ranges vary between labs; pregnancy and altitude shift them — the interval printed on your own report governs. Prices are approximate bands and vary by city and lab.

Haemoglobin myths vs facts

Haemoglobin is India's most-discussed blood number, and the folklore is thick. Here is what the evidence actually says:

MYTH Low haemoglobin just means eat more iron.

Fact: Iron deficiency is the commonest cause, but B12/folate deficiency, thalassaemia trait, chronic disease and blood loss all lower haemoglobin by different routes — and iron doesn't fix those. The MCV and the cause come before the supplement.

MYTH A normal haemoglobin rules out anaemia's causes.

Fact: Early iron deficiency shows low ferritin with normal haemoglobin — stores empty months before anaemia appears. A normal Hb is the end of the story only if iron studies agree.

MYTH High haemoglobin is always healthy.

Fact: High values appear in dehydration (concentrated blood), smoking, lung disease and high altitude — and in polycythaemia. Context decides whether it's fitness or a flag.

MYTH Beetroot and pomegranate fix anaemia fast.

Fact: No food corrects true iron deficiency quickly — diet supports recovery but treatment is iron replacement and finding the cause. Foods help maintain; they rarely rescue.

What matters most with your haemoglobin result

How far below the range? 11.8 against a 12.0 cutoff is borderline; below 8.0 needs urgent assessment — the distance matters more than the flag.
Read the MCV next. Low MCV points toward iron deficiency or thalassaemia trait; high MCV toward B12/folate — the index classifies what the headline only hints at.
Find the leak or the cause. Low iron without a cause found — heavy periods, gut loss, poor intake — means the anaemia returns after treatment. Cause-finding is the treatment.
Thalassaemia trait is common. In India, trait screening (HPLC) matters before iron-loading someone whose microcytosis is genetic, not nutritional. Discuss the full picture with your doctor.

Frequently Asked Questions

What does a low haemoglobin level mean?

Low haemoglobin indicates anaemia, reducing the blood's oxygen-carrying capacity and causing fatigue, pallor, and breathlessness. Further tests identify the type and cause, most commonly iron deficiency.

What causes a high haemoglobin level?

High haemoglobin can result from dehydration, smoking, living at altitude, or certain lung and bone-marrow conditions. Repeat testing and context help determine the cause.

How is haemoglobin different from ferritin?

Haemoglobin measures the oxygen-carrying protein in red cells, while ferritin reflects iron stores: ferritin often falls before haemoglobin does, giving an earlier warning of iron deficiency.³

My Hb is 10.5 but I feel fine. Do I need treatment?

Mild anaemia often causes few symptoms, but the number still deserves an explanation — the next step is finding the type and cause (iron studies, B12, and in India, considering thalassaemia trait), not automatically starting iron. Discuss the workup with your doctor rather than treating the number blindly.

Can I raise my haemoglobin with diet alone?

Diet helps when the cause is iron deficiency, but food alone is slow and cannot fix B12 deficiency, blood loss or thalassaemia trait. The right approach depends on the cause, which is why testing comes before treatment — discuss a plan with your doctor.

Why is my Hb normal but my ferritin low?

Iron stores deplete before haemoglobin falls — ferritin is the early warning, Hb the late one. Low ferritin with normal Hb means iron deficiency without anaemia yet, and it still deserves attention. Discuss it with your doctor rather than waiting for anaemia to develop.

Does smoking really raise haemoglobin?

Yes. Carbon monoxide from smoking reduces oxygen delivery, and the body compensates by making more red cells, raising Hb. It usually normalises after quitting — another reason a high Hb in a smoker needs context before conclusions.

How much does the Hemoglobin test cost in India?

There is no single fixed price — it varies by city, lab, and whether the test is ordered alone or as part of a panel. NABL-accredited labs usually publish their rates online, so it is worth comparing a couple near you. Whatever you pay, the reference range printed on your own report is what counts — discuss the result with your doctor.

Pharmacist's practical notes

The MCV line is where haemoglobin interpretation happens: microcytic (low MCV) versus macrocytic (high MCV) anaemias are different diseases with different treatments, and iron given for a B12 problem — or vice versa — wastes months. If your report flags low Hb, the next line to read is MCV, then ferritin or B12 as the pattern suggests.

Iron supplements are finicky — absorption is blocked by several common medicines, antacids and even tea/coffee taken together — so ask your pharmacist about timing and spacing. And they take months to rebuild stores: stopping when you feel better, before ferritin normalises, is why anaemia so often returns.

In India

In India, haemoglobin is reported in g/dL as part of a CBC, which typically costs &rupee;250–500, varying by city and lab. Thalassaemia screening (HPLC/electrophoresis) is widely available, which matters given how common the trait is.

Where possible, choose a NABL-accredited lab. Anaemia is highly prevalent — but the cause still needs finding, not assuming.

References

Sources cited on this page. PubMed links open the original abstract.

World Health Organization. Haemoglobin concentrations for the diagnosis of anaemia and assessment of severity. WHO/NMH/NHD/MNM/11.1. WHO Press. 2011;:1–6.
Shi H, Chen L, Wang Y, et al. Severity of Anemia During Pregnancy and Adverse Maternal and Fetal Outcomes. JAMA Netw Open. 2022;5(2):e2147046. PMID 35113162 · doi:10.1001/jamanetworkopen.2021.47046
Al-Naseem A, Sallam A, Choudhury S, Thachil J. Iron deficiency without anaemia: a diagnosis that matters. Clin Med (Lond). 2021;21(2):107–113. PMID 33762368 · doi:10.7861/clinmed.2020-0582

Haemoglobin structure and oxygen delivery

Haemoglobin (Hb) is a protein made of four globin chains (two alpha and two beta in adult HbA), each carrying a haem group that can bind one oxygen molecule. Each red blood cell contains approximately 270 million haemoglobin molecules, enabling each cell to carry approximately 1 billion oxygen molecules. This extraordinary oxygen-carrying capacity is what makes blood so much more efficient at delivering oxygen than plasma alone.

Oxygen binds cooperatively: binding of the first oxygen molecule changes haemoglobin's shape, making subsequent binding easier (the "sigmoidal oxygen-dissociation curve"). This property means haemoglobin efficiently loads oxygen in the lungs (high pO₂) and efficiently unloads it in tissues (low pO₂, lower pH, higher CO₂, the Bohr effect), where oxygen demand is greatest.

Interpreting haemoglobin, what the number tells and doesn't tell you

Haemoglobin is measured in grams per litre (g/L) or grams per decilitre (g/dL). Normal ranges:

Adult men: 130–170 g/L (13–17 g/dL)
Adult women: 120–155 g/L (12–15.5 g/dL)
Pregnant women: Below 110 g/L is anaemia (haemodilution physiologically lowers Hb in pregnancy)
Newborns: 140–200 g/L (fetal haemoglobin, HbF, which has higher affinity for oxygen than adult HbA, appropriate for placental extraction of oxygen)

Haemoglobin level alone does not fully characterise anaemia, the MCV, MCH, and blood film provide essential additional information about the type of anaemia (see the FBC section). Important caveats:

Haemoglobin can be falsely elevated in dehydration (haemoconcentration) or in polycythaemia vera
Haemoglobin can be falsely low in overhydration or due to laboratory dilution artefact
A "normal" haemoglobin does not exclude iron deficiency, iron stores can be depleted for months before haemoglobin falls

Haemoglobin variants, HbS, HbC, and thalassaemia

Mutations in the globin genes produce variant haemoglobins with different clinical consequences:

HbS (sickle cell haemoglobin): A point mutation (glutamate → valine at position 6 of the beta chain) causes HbS to polymerise under low oxygen conditions, distorting red cells into a sickle shape. Sickle cells block small blood vessels, causing vaso-occlusive pain crises, stroke, acute chest syndrome, and organ damage. HbSS (sickle cell disease) is a severe chronic condition; HbAS (sickle cell trait) is generally asymptomatic but can be identified by newborn screening (Guthrie test) or haemoglobin electrophoresis.
HbC: Another beta-chain variant; milder sickling in HbSC compound heterozygosity.
Alpha and beta thalassaemia: Reduced production (not structurally abnormal) of alpha or beta chains. Alpha thalassaemia trait causes mild microcytic anaemia; beta thalassaemia major (two copies of beta-zero mutation) requires lifelong blood transfusion or bone marrow transplant.

Medical Disclaimer: This page is for general educational purposes only and does not constitute medical advice. Always consult a qualified doctor for diagnosis and treatment decisions.