Packed Erythrocyte Volumes (PEV) is a medical term used to describe the percentage of red blood cells in whole blood after it has been spun in a centrifuge. The word "erythrocyte" refers to a red blood cell and "packed" indicates that the cells have been dense, tightly packed. The pronunciation of "erythrocyte" is [ih-rith-ruh-sahyt] and "packed" is [pakt]. The IPA phonetic transcription shows that the stress falls on the second syllable of "erythrocyte" and the first syllable of "packed".
Packed erythrocyte volumes, also known as packed cell volume (PCV) or hematocrit, refers to a measurement used in medical and laboratory settings to determine the proportion of red blood cells (erythrocytes) in relation to the total volume of blood. It indicates the percentage of cellular components in a given volume of blood.
To determine packed erythrocyte volume, a small sample of blood is taken from a patient and placed in a specialized test tube known as a hematocrit tube. This tube is then centrifuged, causing the blood to separate into its different components based on density. As a result, the red blood cells settle at the bottom of the tube, while the plasma rises to the top. The packed erythrocyte volume is calculated by measuring the height of the red blood cells after centrifugation and dividing it by the total height of the whole blood sample.
The packed erythrocyte volume value is important in diagnosing various medical conditions, such as anemia, dehydration, polycythemia, and other blood disorders. A low packed erythrocyte volume may indicate conditions associated with low red blood cell count, such as anemia, hemorrhage, or overhydration. Conversely, a high packed erythrocyte volume may suggest conditions like polycythemia vera, a disorder characterized by excessive production of red blood cells.
The packed erythrocyte volume value is often used in conjunction with other blood parameters and clinical assessments to gain a comprehensive understanding of a patient's hematological status and aid in appropriate diagnosis and treatment.