BiomarkersHemoglobin

Blood & iron

Hemoglobin

The oxygen-carrying protein in red blood cells

On your report it may say: Hb, Hgb, Haemoglobin

Hemoglobin carries oxygen around your body. A low level means anaemia, which is very common in India, especially in women. Anaemia has many causes, so hemoglobin alone can't tell you which nutrient, if any, is missing.

Updated 2026-10-26

Typical ranges · g/dL

Women

Low below 12
In range 12–15.5
High 15.5+

Men

Low below 13.5
In range 13.5–17.5
High 17.5+

g/L = g/dL × 10

In pregnancy, below 11 g/dL counts as anaemia.

Ranges vary by lab, age and sex. The range printed on your report applies.

If it's low

You have fewer oxygen carriers than normal (anaemia). The cause needs to be found.

Common causes

  • Iron deficiency
  • B12 or folate deficiency
  • Heavy periods or blood loss
  • Chronic illness or kidney disease
  • Inherited conditions such as thalassaemia trait

What you might notice

  • Tiredness
  • Breathlessness on exertion
  • Pale skin
  • Fast heartbeat
  • Headaches

If it's high

High hemoglobin can come from dehydration, smoking or living at altitude, and occasionally from blood disorders.

Common causes

  • Dehydration
  • Smoking
  • High altitude
  • Testosterone therapy
  • Lung or blood disorders

What you might notice

  • Headaches
  • Dizziness
  • Often none

Testing

Who should test
Everyone as part of a routine CBC, especially women, pregnant women and anyone tired or pale.
How to prepare
No fasting needed.
When to retest
4–8 weeks after starting treatment for anaemia.

What can help

Food sources

Iron-rich foods (see ferritin)B12 and folate foods

See a doctor about any low result, so the cause is found before treating it.

Common questions

Does low hemoglobin always mean low iron?

No. B12, folate, blood loss, illness and inherited traits can all lower it.

Why doesn't SYNC suggest iron from this?

Because the cause has to be confirmed first, usually with ferritin.

Explore further

Sources

  1. MedlinePlus (US National Library of Medicine): Hemoglobin test
  2. NIH Office of Dietary Supplements: Iron fact sheet for health professionals

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For general education only, not medical advice. Ranges shown are typical for adults; the range printed on your lab report applies. Talk to a qualified doctor about your results.