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Formed Elements and Associated Tests • Leukocyte or White Blood Cell (WBC) Count – Complete WBC count includes the total number of all types of white blood cells in a microliter of blood – Normal WBC or leukocyte counts in adults range from approximately 4.5 to 11 thousand/mm3 Formed Elements and Associated Tests • Leukocyte or White Blood Cell (WBC) Count – Elevated level usually indicates infection – If grossly elevated, leukemia could be the cause Formed Elements and Associated Tests • Leukocyte or White Blood Cell (WBC) Count – Low level usually indicates a viral infection or autoimmune deficiency – Extreme bacterial infection also can destroy enough white blood cells to significantly reduce their numbers Formed Elements and Associated Tests • Leukocyte or White Blood Cell (WBC) Count – Manual method is through use of hemocytometer – MAs require further training to perform manual WBC count in a medical laboratory Formed Elements and Associated Tests • Differential White Blood Cell Count – Determines the percentages of each type of leukocyte in a given sample – Most commonly performed by the automated analyzer Formed Elements and Associated Tests • Differential White Blood Cell Count – Types of leukocytes that are counted are neutrophils, eosinophils, basophils, lymphocytes, and monocytes – Results may be read as percentages or as numbers in a given quantity depending on the laboratory and equipment being used. count, (A) the slide is examined under oil immersion. (B) Cells are viewed using a bright light and 100× magnification. FIGURE 48-13 Types of white blood cells. Preparing Slides • Refer to Procedure 48-4: Preparing Slides for details about this technique. • MAs require further training to perform this test in a medical laboratory; it is commonly performed in an educational setting to further understanding. PROCEDURE 48-4 Preparing Slides FIGURE A Blood smear. PROCEDURE 48-4 (continued) Preparing Slides FIGURE B Blood smear. PROCEDURE 48-4 (continued) Preparing Slides FIGURE C Blood smear. PROCEDURE 48-4 (continued) Preparing Slides FIGURE D Blood smear. (continued) Preparing Slides FIGURE E Wright’s staining process. (continued) Preparing Slides FIGURE F Wright’s staining process. (continued) Preparing Slides FIGURE G Wright’s staining process. (continued) Preparing Slides FIGURE H Wright’s staining process. Formed Elements and Associated Tests • Neutrophils – Act as the body's primary defense and make up the largest percentage of white blood cells – Granules are neutral in color on laboratory-stained slides Formed Elements and Associated Tests • Neutrophils – Phagocytosis • The process in which the neutrophil surrounds, swallows, and digests the bacteria – Segmented • Mature cells with a nucleus that is divided into multiple segments connected by small thin threads Formed Elements and Associated Tests • Neutrophils – Nonsegmented neutrophils • Immature cells; also called stabs or bands – Nicknamed a "shift to the left" and indicates an early white blood cell response Formed Elements and Associated Tests • Neutrophils – Tend to increase in response to infection; may also increase from hemorrhage, cancer, poisoning, hemolysis, and inflammation – Tend to decrease in response to a virus or serious bacterial infection FIGURE 48-14 Phagocytosis. The cell engulfs and digests a bacterium. FIGURE 48-15 Band and segmented neutrophils. Formed Elements and Associated Tests • Eosinophils – White blood cells assumed also to be produced by the bone marrow – A large number can indicate a parasitic condition or the presence of certain allergic conditions – Have granules that produce a red color on laboratory-stained slides – Make up less than 3 percent of white blood cell volume Formed Elements and Associated Tests • Basophils – Thought to be produced by the bone marrow – Produce heparin – Increased amounts may be found in patients who have had their spleen removed or in patients with excessive exposure to radiation. Formed Elements and Associated Tests • Basophils – Contain the vasodilator histamine – Appear in tissues where an allergic reaction is occurring Formed Elements and Associated Tests • Basophils – Concentration of basophils may contribute to the severity of allergic reactions – Normal laboratory results generally show basophils as less than 1 percent of white blood cell volume. Formed Elements and Associated Tests • Lymphocytes – White blood cells produced in the bone marrow and in the lymphoid tissue – Primary function is to produce antibodies against foreign substances – Small and large, and can proliferate into B and T cells Formed Elements and Associated Tests • Lymphocytes – B cells may convert into plasma cells – T cells can produce helper cells, cytotoxic cells, and suppressor cells Formed Elements and Associated Tests • Lymphocytes – Do not have granules and are nonsegmented – Make up the second largest volume of white blood cells, comprising 25 to 30 percent – To diagnose an individual with HIV, testing is performed to evaluate the type and amount of T cells present. Formed Elements and Associated Tests • Monocytes – White blood cells formed in the bone marrow from stem cells; assist in phagocytosis – Ingest foreign particles or bacteria that the neutrophils are unable to digest – Assist in cleaning up cellular debris that may have been left from the infection Formed Elements and Associated Tests • Monocytes – Increase is seen in patients with tuberculosis, typhoid, and Rocky Mountain spotted fever – In a typical adult, make up 3 to 7 percent of the total white blood cell volume Formed Elements and Associated Tests • Platelets and Coagulation Studies – Platelets (thrombocytes): the smallest cells found in the blood; formed in the bone marrow – Live for about ten days and are continuously reproduced – Assist in the clotting of blood to stop bleeding or assist in healing Formed Elements and Associated Tests • Platelet Counts – Typically between 150,000 and 400,000 platelets/mm3 in adults – Testing is typically performed in an outside laboratory or by automated testing. Formed Elements and Associated Tests • Platelet Counts – Over 750,000 (thrombocytosis) – Less than 50,000 (thrombocytopenia) – Severely low counts can lead to internal bleeding and even death Formed Elements and Associated Tests • Prothrombin Time (PT, Protime) International Normalized Ratio (INR)/(PT/INR) – PT • coagulation test that measures the amount of time it takes to form a clot Formed Elements and Associated Tests • Prothrombin Time (PT, Protime) International Normalized Ratio (INR)/(PT/INR) – INR • Standard protocol that allows specimens performed at different laboratories to have consistent results • Does not reveal specific bleeding disorders in patients with liver failure or other systemic diseases Formed Elements and Associated Tests • Prothrombin Time (PT, Protime) International Normalized Ratio (INR)/(PT/INR) – Typically used to screen patients with symptoms of bleeding – Protime for an average healthy adult will show clotting at 10–14 seconds – Higher than 30 seconds (or 4.5 INR) indicates a risk for bleeding; more than 40 seconds is considered critical Formed Elements and Associated Tests • Prothrombin Time (PT, Protime) International Normalized Ratio (INR)/(PT/INR) – Elevated levels seen in patients with severe bone marrow depression, cancer, liver or collagen diseases, pancreatitis, disseminated intravascular coagulation, and toxic shock syndrome Formed Elements and Associated Tests • Prothrombin Time (PT, Protime) International Normalized Ratio (INR)/(PT/INR) – Decreased levels seen in patients with myocardial infarction, multiple myeloma, pulmonary embolus, or thrombophlebitis Formed Elements and Associated Tests • Partial Thromboplastin Time (PTT) – Determines the length of time it takes for a fibrin clot to form – Can help to determine which specific clotting factors are affected – Commonly used to determine the effectiveness of anticoagulant therapy Formed Elements and Associated Tests • Partial Thromboplastin Time (PTT) – Helps to screen for bleeding tendencies and identify more precise causes – Normal findings are typically 60–70 seconds. Other Blood Tests • Common panels include the lipid panel and the liver panel • Lipid panel – Cholesterol, triglycerides, and highdensity lipoproteins (HDL) • Liver panel – SGOT and SGPT • CBC • Coagulation studies Other Blood Tests • Refer to the following tables in the student text: – Table 48-1: Common Blood Test Groups – Table 48-2: Common Laboratory Tests and Their Normal Values – Table 48-3: Common Blood Chemistry Tests TABLE 48-1 Common Blood Test Groups TABLE 48-2 Common Laboratory Tests and Their Normal Values TABLE 48-3 Common Blood Chemistry Tests TABLE 48-3 (continued) Common Blood Chemistry Tests TABLE 48-3 (continued) Common Blood Chemistry Tests Other Blood Tests • Comprehensive Metabolic Panel (CMP) – Screening tool used to: • Evaluate organ function • Check for common disorders • Monitor the progress of current conditions and response to medications – Includes 14 essential tests included among the basic metabolic panel, renal panel, liver function tests, and electrolytes Other Blood Tests • Comprehensive Metabolic Panel (CMP) – Abnormality in any area may indicate a need for further, more-specific testing – Recommended that the patient fast for 12 hours before testing – Normal values can be found in Table 483 Common Blood Chemistry Tests Other Blood Tests • Glucose – A simple sugar required by all body cells to produce energy; circulates in the blood – Used to give energy to the cells Other Blood Tests • Glucose – Hyperglycemia • When glucose cannot get into the cells for consumption, it builds up in the blood and clogs up the organs – Critical, life-threatening levels above 700 mg/dL while fasting Other Blood Tests • Glucose – Hypoglycemia (low blood sugar) • Can happen rapidly and can become lethal before treatment may be considered – Suspected blood glucose abnormalities are always treated as if they are low, until blood testing can be performed.