How reports print it
What it shows
The protein in red blood cells that carries oxygen from the lungs to every tissue. One of the main values of a complete blood count.
Units and conversion
Base unit: g/L.
- 1 g/dL = 10 g/L · 1 g/L = 0.1 g/dL
Typical ranges
Your laboratory’s range comes first — it is printed on the report next to the result. Below is one laboratory’s adult range with its method: a reference, not a rule.
| Who | Range, g/L |
|---|---|
| Men, 18–44 years | 132–173 |
| Women, 18–44 years | 117–155 |
| Men, 45–65 years | 131–172 |
| Women, 45–65 years | 117–160 |
| Men, 66 years and older | 126–174 |
| Women, 66 years and older | 117–161 |
Range source: Лаборатория Хеликс — Общий анализ крови (без лейкоцитарной формулы и СОЭ)
Guideline thresholds
They apply on top of the range, for adults outside pregnancy. They are a reason to talk to a doctor, not a conclusion.
- WHO (2024): the haemoglobin cut-off for adults aged 15–65 is 120 g/L for non-pregnant women and 130 g/L for men.
- Guideline on haemoglobin cutoffs to define anaemia in individuals and populations — World Health Organization, 2024
Critical values
Urgent thresholds per the source below: ≤ 70 g/L or ≥ 200 g/L. If your report has such a value, see a doctor today; if you feel unwell right now, call 103 or 112.
- Critical values comparison: a College of American Pathologists Q-Probes survey of 163 clinical laboratories — Archives of Pathology & Laboratory Medicine, 2007
Good to know
In 2024 WHO updated haemoglobin cut-offs for adults aged 15–65: 120 g/L for non-pregnant women and 130 g/L for men; smoking raises the cut-off by 3–6 g/L. Some laboratories print haemoglobin in g/dL, others in g/L: 13.5 g/dL = 135 g/L.
Why it can be higher
Common reasons discussed with a doctor. This is not a diagnosis.
- Dehydration: with less fluid the blood is more concentrated
- Smoking
- Living at high altitude
- Conditions in which the bone marrow makes more red cells — a doctor looks into them
Why it can be lower
- Blood loss, including heavy periods
- Low iron, vitamin B12 or folate
- Pregnancy: plasma volume grows faster than the red cell count
- Chronic inflammatory and kidney conditions
What to ask a doctor
- Is it worth checking ferritin, B12 and folate?
- How does this result compare with my earlier tests?
- When does a repeat test make sense?
Whom to see
A GP or internist; with marked changes, a haematologist on referral.