The short explanation
Hb stands for haemoglobin, the protein in red blood cells that carries oxygen. A result below the lab's reference range means anaemia; how far below tells a clinician how significant it is. For non-pregnant adult women the WHO uses 12 g/dL as the usual cut-off, with a different one in pregnancy. The number alone does not tell you the cause. Other values on the same report — such as the size of the red cells (MCV) — and further tests like ferritin help work out whether it is iron, B12, folate or something else.
What depends on your situation
The parts of this that change from woman to woman. Uncertainty is stated, not hidden.
- How quickly it fell matters too. A low Hb that developed slowly is often better tolerated than the number suggests; one that dropped quickly needs faster attention. Labs vary slightly in their ranges, so read the number against the range printed beside it.
- Treatment and how quickly it should be repeated depend on the cause and how low it is.
What this answer cannot determine
The boundary of online education. These need a clinician who can see you.
- This cannot interpret your report or say what caused your anaemia. A clinician needs to read the whole blood count and your history together.
Questions for your clinician
Take these with you. You can add any of them to an appointment card.
- How low is my Hb, and how urgent is it?
- What do the other numbers on the report suggest about the cause?
- Do I need more tests, such as ferritin, B12 or a thalassaemia test?
- When should we repeat it to see if treatment is working?
When to seek help
Clinician-approved guidance for this topic. When in doubt, being seen is never the wrong choice.
- Get emergency care now (call 112 or 108) for fainting, chest pain, severe breathlessness, or signs of bleeding such as black stools or vomiting blood.
- See a clinician within days to go through a low result, sooner if you are pregnant or feel very unwell.
Sources
The evidence this explanation is built on.
- Hemoglobin test MedlinePlus (US National Library of Medicine)
- Anaemia World Health Organization
- Iron deficiency anaemia NHS
Who wrote and reviewed this
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- Author
- AskHer Editorial (AI-assisted draft) AskHer's editorial team — not an individual clinician Works in English, தமிழ், हिन्दी
- Clinical reviewer
- Nobody yet No clinician has signed this answer off, and no person on the editorial team has read it yet. That is what the “Written with AI assistance” label means. It is queued for an editor to read, and then for a clinician who works in this area. The sources it was drafted against are listed above.
- Review status
- Written with AI assistance — not yet reviewed by a person
- Last reviewed
- Not yet reviewed by a person
- Version
- 1
Correction history
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No corrections have been made since this answer was first published.
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