Blood Laboratory Exercises – Review Flashcards

Identification of Formed Elements (Microscope & Model)

• Be able to visually distinguish each formed element on a blood smear slide and on the 3-D classroom model.
  • Erythrocyte (RBC)
  • Biconcave, anucleate, pink/red, most abundant.
  • Leukocytes (WBCs) – 5 distinct morphologies:
  • Neutrophil (granulocyte)
    • Multi-lobed nucleus (3-5 lobes), pale lilac granules.
  • Eosinophil (granulocyte)
    • Bilobed nucleus, large red-orange granules.
  • Basophil (granulocyte)
    • U/S-shaped nucleus often obscured, dark blue-black granules.
  • Lymphocyte (agranulocyte)
    • Large round nucleus, thin rim of cytoplasm; small & large forms.
  • Monocyte (agranulocyte)
    • Kidney/bean-shaped nucleus, abundant gray-blue cytoplasm.
  • Platelet (Thrombocyte)
  • Tiny purple specks; fragments of megakaryocytes.

Granulocytes vs. Agranulocytes

• Granulocytes: neutrophils, eosinophils, basophils
  • Contain visible cytoplasmic granules, lobed nuclei, short life span.
• Agranulocytes: lymphocytes, monocytes
  • Lack obvious granules, spherical/kidney nuclei, longer life span.

Exercise 20.3 – Determination of Leukocyte Counts

• Purpose
  • Detect infection, inflammation, allergic response, leukemia, immunodeficiency.
• Equipment / Procedure (Manual Differential)
  1. Obtain fresh EDTA blood.
  2. Prepare & stain smear (Wright, Giemsa).
  3. Under oil immersion, count 100 WBCs using battlement method.
  4. Record number of each type → calculate %.
• Normal Differential Percentages
  • Neutrophils ≈ 50\text{–}70\%
  • Lymphocytes ≈ 20\text{–}40\%
  • Monocytes ≈ 2\text{–}8\%
  • Eosinophils ≈ 1\text{–}4\%
  • Basophils ≈ 0.5\text{–}1\%
• Clinical Meaning of Deviations
  • ↑ Neutrophils → acute bacterial infection, stress; ↓ → aplastic anemia.
  • ↑ Lymphocytes → viral infection, chronic leukemia; ↓ → HIV, radiation.
  • ↑ Monocytes → chronic infection (TB), recovery phase; ↓ → corticosteroids.
  • ↑ Eosinophils → parasitic worms, allergies; ↓ → stress response.
  • ↑ Basophils → myeloproliferative disease, allergies; ↓ → acute infection.

Exercise 20.4 – Determination of Hematocrit

• Definition: Packed RBC volume as % of whole blood.
• Formula
  \text{Hematocrit (\%)} = \frac{\text{Height of RBC column}}{\text{Total height of blood column}} \times 100
• Equipment
  • Heparinized microcapillary tube, clay sealant, microcentrifuge, ruler or reader card.
• Normal Values
  • Males ≈ 42\text{–}52\%
  • Females ≈ 37\text{–}47\%
• Interpretation
  • Anemia = low hematocrit (< 37\% F, < 42\% M).
  • Causes: blood loss, iron/B₁₂ deficiency, marrow failure.
  • Polycythemia = high hematocrit (> 52\% M, > 47\% F).
  • Causes: dehydration, COPD, polycythemia vera, high altitude.
  • Plasma level (upper yellow layer) indicates hydration & protein status.

Exercise 20.5 – Determination of Hemoglobin Content

• Purpose: Quantify O₂-carrying protein; more direct than hematocrit.
• Common Classroom “Equipment”
  • Talquist paper/color scale OR spectrophotometer with Drabkin reagent.
• Procedure (Colorimetric)
  1. Prick finger, apply drop to Talquist paper.
  2. Compare dried spot to standard color chart → read g\/dL.
• Normal Ranges
  • Males 13\text{–}18\ g\/dL, Females 12\text{–}16\ g\/dL.
• Anemia Threshold
  • < 13\ g\/dL (M) or < 12\ g\/dL (F).

Exercise 20.7 – Determination of Blood Type (ABO & Rh)

• Key Serum Contents
  • Anti-A and/or Anti-B antibodies naturally present; Anti-D acquired.
• Reagents: Commercial antisera (Anti-A, Anti-B, Anti-D).
• Procedure
  1. Place separate drops of blood on typing card.
  2. Add one drop of each antiserum; stir with separate sticks.
  3. Observe for agglutination (clumping) within 2 min.
• Reading Results
  • Agglutination in Anti-A only → Type A.
  • Agglutination in Anti-B only → Type B.
  • Agglutination in both → Type AB.
  • No agglutination → Type O.
  • Agglutination in Anti-D → Rh⁺; none → Rh⁻.
• Definitions
  • Antigen (Ag): RBC surface glycoprotein (A, B, D).
  • Antibody (Ab): Plasma protein that binds specific Ag.
  • Agglutination: Antibody-mediated clumping of RBCs; indicator of reaction.
• Transfusion Compatibility(Must match both ABO & Rh unless emergent)
  • Type O⁻: universal donor of RBCs.
  • Type AB⁺: universal recipient of RBCs.
  • Example: Type A⁻ can receive A⁻ or O⁻; can donate to A⁺/A⁻/AB⁺/AB⁻.
  • Use cross-matching to confirm in practice.

Functional Summary of Formed Elements & Plasma

• Erythrocytes
  • Transport \text{O}2 via \text{Hb}; carry \text{CO}2 on globin chains; maintain pH (buffering).
  • Life span ≈ 120 days; removed by spleen/liver macrophages.
• Neutrophils
  • First responders; phagocytose bacteria; release lysozyme & defensins; form pus.
• Eosinophils
  • Combat multicellular parasites; modulate allergic responses; inactivate histamine.
• Basophils
  • Release histamine (vasodilator) & heparin (anticoagulant); intensify inflammation.
• Lymphocytes
  • B-cells → plasma cells → antibodies; T-cells → cell-mediated immunity; NK cells.
• Monocytes
  • Differentiate into macrophages in tissues; present antigens; chronic infection defense.
• Platelets
  • Adhere to damaged endothelium; release \text{ADP},\ \text{TxA}_2; form platelet plug; initiate clotting cascade.
• Plasma (55 % of whole blood)
  • \sim 92 % water + proteins (albumin, globulins, fibrinogen) + nutrients, wastes, hormones, gases; transports & buffers.

Ethical, Clinical & Real-World Connections

• Accurate blood counts prevent transfusion reactions, guide chemotherapy, detect anemia in pregnancy.
• Overuse of broad-spectrum antibiotics elevates eosinophils via drug allergies.
• Altitude training exploits physiologic polycythemia; EPO doping = ethical issue in sports.
• Rh incompatibility → hemolytic disease of the newborn; prevented with Rho(D) immune globulin.

Key Equations & Statistics (LaTeX Notation)

• Hematocrit: Hct = \frac{h{RBC}}{h{total}} \times 100
• Hemoglobin–O₂ capacity: 1\ g\ \text{Hb} \approx 1.34\ mL\ \text{O}_2
  (⇒ 15 g\/dL blood carries \approx 20\ mL\/dL O₂).
• Mean Corpuscular Volume: MCV = \frac{Hct (\% ) \times 10}{RBC (\times 10^6\/\mu L)}
  Used to classify anemias.

Study Tips & Mnemonics

• Never Let Monkeys Eat Bananas → Neutro- Lympho- Mono- Eosino- Baso- (relative abundance high → low).
• For ABO typing interpretation: "Agglutination with Antiserum means Antigen A present."
• Hematocrit & Hemoglobin roughly correlate: Hb\,(g\/dL) \approx Hct\,(\%) \/ 3.