When does the hemoglobin concentration of the blood increase or decrease? What is the function of RBCs? When does RBC count increase or decrease? What is the function WBCs? When does WBC count increase or decrease? What is the function of platelets? When does the platelets count increase or decrease? What indicated when MCV increases or decreases? What is indicated when MCH increases or decreases? What is indicated when MCHC increases or decreases? What is the difference between blood plasma & serum? When does packed cell volume increase or decrease? Which factors affect the accuracy of the test of RBC osmotic fragility? Which factors affect the osmotic fragility of RBCs?