Ans. c. High packed cell volume Packed cell volume Packed cell volume (PCV) or hematocrit determines the percentage of red blood cells in the plasma. Decrease in hematocrit PCV in the early hours after acute hemorrhage is usually the result of volume resuscitation rather than ongoing blood loss. The body adjusts to severe hemorrhage by expanding the circulating volume at the expense of extravascular fluid. However, within several hours after hemorrhage plasma volume begins to increase due to shift of interstitial fluid into vascular space RBCs cannot be replaced quickly as the bone marrow takes approximately ten days to produce mature RBCs. As a result PCV done several hours after bleeding episode will show more accurate picture of the hematocrit (Le. decreased PCV). The changes in hematocrit show poor correlation with blood volume deficits and erythrocyte deficits in acute hemorrhage. Mean corpuscular volume MCV, MCH and MCHC normal: Normocytic, normochromic anemia, most often caused by acute blood loss Decreased MCV, MCH, and MCHC: Microcytic, hypochromic anemia, most often caused by iron deficiency Increased MCV, variable MCH and MCHC: Macrocytic anemia, most often caused by Vitamin 113,2 deficiency (due to pernicious anemia) and folic acid deficiency Reticulocyte count Causes of Reticulocytosis (Increased RBC Production): Acute blood loss or hemorrhage Post-splenectomy Acute hemolytic anemia (Microangiopathic anemia): Autoimmune hemolytic anemia Hemoglobinopathy (Sickle cell anemia, Thalassemia major) Post-anemia treatment: Folate supplementation, Iron supplementation, Vitamin B1, Neutrophil count Neutrophil count is increased in response to trauma and stress.