HCT stands for hematocrit and is defined as the percentage of red blood cells in the blood. Synonyms for HCT include packed cell volume (PCV), erythrocyte volume fraction (EVF), and red cell volume. These terms are commonly used in medical settings, and they all refer to the same measure of the volume of red blood cells in the blood. Hematocrit is an important component of a complete blood count (CBC) test, which is used to evaluate overall health and diagnose various medical conditions. The use of different terms for HCT allows medical professionals to communicate effectively and accurately when discussing blood related issues.