PCV stands for Packed Cell Volume, which is a measurement of the proportion of blood that is made up of cells. It is usually reported as a percentage and is measured by taking a small blood sample and spinning it in a centrifuge, which causes the red blood cells to separate from the plasma, the liquid part of your blood. A PCV test is done to diagnose anemia or polycythemia in patients, and it is generally done along with a full blood count test that is conducted to estimate the need for any blood transfusions and monitor the effectiveness of treatment. A lower number of the PCV means that the red blood cell count is less, which can be due to many reasons such as blood loss, cell destruction, and less bone marrow production. An increased PCV generally means that the person is dehydrated, and there is a higher number of RBC production. Polycythemia Vera (PCV) is a rare blood disorder in which the body makes too many red blood cells, leading to a thickening of the blood. It can be associated with an elevated platelet count and an enlarged spleen. This slow-developing disease is linked to a mutation in the gene JAK2, which regulates the production of blood cells.