Exam 1 Review:  Chapter 17:  Hematology Testing

phlebotomist - A technician who draws blood for analysis or transfusion.

buffy coat - The thin pale (white, gray or yellow) layer of white blood cells and platelets which is found on top of the mass of red blood cells when whole blood is centrifuged.

hematocrit (HCT) - The percentage by volume of packed red blood cells in a given sample of blood after centrifugation; the average for healthy adults is 45%.  aka PCV = packed cell volume

reticulocyte count - A clinical laboratory hematology test which measures the percentage of reticulocytes (slightly immature red blood cells) in blood; a special stain is used to identify reticulocytes, because they contain remnants of RNA; the count is elevated after hemorrhage or in most anemias, and is depressed in nutritional deficiencies.

differential white blood cell count - A clinical laboratory hematology test which measures the relative numbers of the five basic classes of white blood cells (WBCs) in the blood; it also includes information about abnormal cell structure and the presence of immature cells; the test is useful in the diagnosis and management of infections, leukemias and lymphomas, and various other diseases; reference ranges for healthy adults are neutrophils 60-70%, eosinophils 2-4%, basophils 0.5-1.0%, lymphocytes 20-25%, and monocytes 3-8%.

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