How reports print it
HCTHtHematocrit
What it shows
The share of blood volume taken up by red cells, in percent.
Units and conversion
Base unit: %.
- 1 L/L = 100 % · 1 % = 0.01 L/L
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, % |
|---|---|
| Men, 18–44 years | 39–49 |
| Women, 18–44 years | 35–45 |
| Men, 45–65 years | 39–50 |
| Women, 45–65 years | 35–47 |
| Men, 66 years and older | 37–51 |
| Women, 66 years and older | 35–47 |
Range source: Лаборатория Хеликс — Общий анализ крови (без лейкоцитарной формулы и СОЭ)
Good to know
Sometimes haematocrit is printed as a fraction: 0.42 L/L = 42%.
Why it can be higher
Common reasons discussed with a doctor. This is not a diagnosis.
- Dehydration
- Smoking
- Living at high altitude
- Increased red cell production — a doctor looks into it
Why it can be lower
- Blood loss
- Low iron, B12 or folate
- Pregnancy
- Excess fluid in the body
What to ask a doctor
- How does haematocrit fit with haemoglobin?
- Can how much I drink before the test affect it?
Whom to see
A GP or internist.