Hematókrít

Hematókrít, or hematocrit, is the proportion of blood volume that consists of red blood cells. Expressed as a percentage, it reflects the mass of erythrocytes relative to the total blood volume and is a central value in the complete blood count (CBC).

Measurement is usually by centrifugation of a sample of anticoagulated blood in a capillary or microhematocrit tube, after which the packed cell volume is divided by the total volume. Automated hematology analyzers estimate hematocrit using impedance or optical methods, often as part of a CBC.

Normal values vary with age and sex and between laboratories. In healthy adults, typical ranges are roughly 40-54% for men and 36-46% for women; newborns often have higher values that decline with age. Values can be influenced by altitude, smoking, hydration status, pregnancy, and recent exercise, among other factors.

Clinical significance: A low hematocrit indicates reduced red cell mass or increased plasma volume, commonly due to anemia or blood loss. A high hematocrit can indicate polycythemia or dehydration. Hematókrít is interpreted alongside hemoglobin concentration and red blood cell count, and its evaluation may be affected by RBC size and distribution.

Limitations: Hematókrít is not a direct measure of red blood cell mass and can be influenced by sample handling and instrument calibration, as well as by acute shifts in plasma volume. It is most informative when considered within a broader hematologic assessment.