Hematocrit is a term that refers to the volume of red blood cells present within the blood. This measurement is often used to assess a person's overall blood health or as a diagnostic tool to detect conditions such as anemia or polycythemia. While there aren't many synonyms for hematocrit in the strictest sense, there are numerous related terms that can help to expand one's understanding of this important blood parameter. Some of these related terms include blood volume, erythrocyte volume fraction, packed cell volume, and red cell volume. Other related measurements of blood health include hemoglobin levels, white blood cell count, platelet count, and blood viscosity.