Hematocrit
The percentage of blood volume made up of red blood cells.
| Typical reference range (male) | 38.5–50 % |
| Typical reference range (female) | 35–45 % |
Ranges vary by laboratory, method, age and sex: always use the range printed on your own report. Why labs differ.
What it measures
Hematocrit is the proportion of whole blood occupied by red cells. It is usually calculated from RBC count and MCV and typically runs about three times the hemoglobin value.
Why it matters
Like hemoglobin, it identifies anemia and erythrocytosis. Values above ~52-54% raise concern for blood thickening and clotting risk, a key safety metric during testosterone therapy.
What a high result can mean
Causes include dehydration, testosterone or EPO use, smoking, sleep apnea, altitude, chronic lung disease and polycythemia vera.
What a low result can mean
Low hematocrit indicates anemia or overhydration, with the same causes as low hemoglobin.
What affects the result
Strongly affected by hydration. Testosterone dose and formulation influence the increase. Interpret with hemoglobin and RBC indices.
Units and conversion
Usually reported in %.
- From L/L: multiply by 100 to get %
- From fraction: multiply by 100 to get %
Also called on lab reports
Hct, Haematocrit, PCV, Packed Cell Volume
Related tests: Red Blood Cells
This page is educational and does not replace advice from a healthcare professional.