Differential Count and Blood Smear Preparation NOTES PDF

Differential Count and Blood Smear Preparation Differential Count a.k.a. leukocyte differential count, peripheral differential, white blood cell morphology, WBC differential, diff Formal name: White Blood Cell Count Differential Differential Count normally...

Differential Count and Blood Smear Preparation Differential Count a.k.a. leukocyte differential count, peripheral differential, white blood cell morphology, WBC differential, diff Formal name: White Blood Cell Count Differential Differential Count normally run as part of CBC determine the relative no. of each type of WBC present in peripheral blood expressed as: percentage (relative numbers of each type of WBC in relationship to the total WBC) absolute value (percentage x total WBC) Uses of Differential Count assesses the ability of the body to respond to and eliminate infection detects the severity of allergic and drug reactions detects the response to parasitic and other types of infection essential in evaluating the reaction to viral infections evaluates response to chemotherapy identify various stages of leukemia  Manual Differential Count Approximates the WBC ct # WBC / hpf WBC/mm3 2-4 4,000-7,000 4-6 7,000-10,000 7-10 10,000-13,000 10-20 13,000-18,000 Differential Count Five basic white blood cell types: Neutrophils Lymphocytes Monocytes Eosinophils Basophils Neutrophils a.k.a. : Segmented Neutrophils, Segs, Polymorphonucleocytes, Polymorphonuclear Neutrophils, Polys, PMNs the most common of the WBCs and serve as the primary defense against infection Neutrophils Neutrophilia typical response to infection or serious injury : bacterial infection inflammatory disease : appendicitis various bone marrow disorders : chronic myelogenous leukemia Stab Band/staff cells seen early in the response to infection “shift to the left” = can be the earliest sign of a WBC response, even before the WBC becomes elevated Eosinophils Eos play a role in allergic disorders and in combating parasitic infections Eosinophils Eosinophilia increase in response to allergic disorder; allergies inflammation of the skin scarlet fever parasitic infections increase in response to various bone marrow disorders: eosinophilic leukemia Eosinophils Eosinopenia Stress Steroid exposure Anything that may suppress WBC production generally Lymphocytes Lymphs play both an immediate and delayed role in response to infection or inflammation Lymphocyte Lymphocytosis Viral infections Infectious mononucleosis Lymphocytic leukemia Cancer of the bone marrow (CLL) Radiation therapy Monocytes Monos cells respond to inflammation, infection and foreign bodies by ingesting and digesting the foreign material Monocyte Monocytosis increase in response to infection of all kinds as well as to inflammatory disorders Brucellosis Tuberculosis certain malignant disorders, including leukemia : Monocytic leukemia Monocyte Subacute bacterial endocarditis Typhoid fever Rickettsial infections Collagen disease Hodgkin’s disease Gaucher’s disease Basophils Basos Basophilia Leukemia chronic inflammation the presence of a hypersensitivity reaction to food radiation therapy Differential Count Four General Steps: 1. Prepare blood smear. 2. Stain the smear. 3. Count the cells. 4. Report. I. Blood Smear Preparation I. Blood Smear Preparation Types of Blood Smear: cover glass smear wedge smear spun smear buffy coat smear thick blood smear I. Blood Smear Preparation Methods: 2-Coverslip Method (Ehrlich’s Method) Two-glass slide Method (Wedge Method) Glass slide - Coverslip Method (Beacom’s Method) Spinner’s Method I. Blood Smear Preparation Prerequisites for proper blood smear: 1. Slides and coverslips should be clean and free from grease. 2. The size of the blood drop should not be too large or too small. 3. Smearing should be done quickly before coagulation sets in. 4. Proper angle and pressure of the spreader should be observed as to produce an ideal smear. I. Blood Smear Preparation Factors that differentiate the thickness of blood smear: Size of the drop Angle between the slide and spreader Speed of spreader Pressure of spreader I. Blood Smear Preparation Features of a Well-stained (Wedge) Peripheral Blood Film: The film is 2/3 to ¾ the length of the slide. The film is finger-shaped, very slightly rounded at the feather edge, not bullet shaped; this provides the widest area for examination. The lateral edges of the film are visible. The film is smooth without irregularities, holes, or streaks. When the slide is held up to the light, the thin portion (feather edge) of the film has a “rainbow” appearance. The whole drop of blood is picked up and spread. I. Blood Smear Preparation Pros and Cons of Coverslip vs Slide: 1. “Perfect coverslip” smears are better than “perfect slide”smears because leucocytes are more evenly distributed. 2. It is difficult to make consistently “perfect” coverslip smears because blood is thick and viscous, and coverslips are fragile. I. Blood Smear Preparation Pros and Cons of Coverslip vs Slide: 3. Anyone can easily learn to make “perfect” slide smears. 4. The average quality of slide smears is better than that of average coverslip smears. I. Blood Smear Preparation Methods of Drying Blood Smear: 1. air drying 2. use of low flame like bunsen burner 3. use of oven 4. immersion in methyl alcohol or absolute alcohol for 1-2 minutes