Red blood cell distribution width and small cells, causing the RDW to be elevated. An elevated RDW (red blood cells of unequal sizes) is known as anisocytosis. An elevation in the RDW is not characteristic of all anemias. Anemia of chronic disease, hereditary spherocytosis, acute blood loss, aplastic anemia (anemia resulting from an inability of the bone marrow to produce red blood cells), and certain hereditary hemoglobinopathies (including some cases of thalassemia minor) may all present with a normal RDW. The "width" in RDW-CV is sometimes thought to be "misleading," since it in fact is a measure of deviation of the "volume" of RBCs, and
Blood red dark red state, but quickly oxygenates upon exposure to air, turning a brighter shade of red. This happens more quickly with smaller volumes of blood such as a pinprick and less quickly from cuts or punctures that cause greater blood flows such as a puncture in the basilic vein: all blood collected during a phlebotomy procedure is deoxygenated blood, and it does not usually have a chance to become oxygenated upon leaving the body. Arterial blood, which is already oxygenated, is also already a brighter shade of red— this is the blood see from a pulsating neck, arm, or leg