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.

FIGURE For a differential white blood cell count, (A) the slide is examined under oil immersion. (B) Cells are viewed using a bright light and 100× magnification.

FIGURE 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.

PROCEDURE 48-4 (continued) Preparing Slides FIGURE E Wright’s staining process.

PROCEDURE 48-4 (continued) Preparing Slides FIGURE F Wright’s staining process.

PROCEDURE 48-4 (continued) Preparing Slides FIGURE G Wright’s staining process.

PROCEDURE 48-4 (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 Phagocytosis. The cell engulfs and digests a bacterium.

FIGURE 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 high- density 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

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 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.