Lecture Notes: Routine Lab Work and Blood Tests

Introduction

• Purpose of labs:
  • Diagnose causes of symptoms (fatigue, weight loss, etc.)
  • Assess blood loss
  • Perform DNA testing
  • Diagnose blood disorders (anemia, leukemia)
  • Pre-surgery screening
  • Monitor treatment/medication response
• Typical lab process: Tourniquet, disinfection, needle, blood draw, analysis

Complete Blood Count (CBC)

• Components of CBC:
  • White Blood Cells (WBC or Leukocytes): Fight infection (normal range: 5,000 to 10,000)
  • Red Blood Cells (RBC or Erythrocytes): Transport oxygen/CO2, live 100-120 days
  • Hemoglobin (Hgb): Transports oxygen/CO2
  • Hematocrit (HCT): Measures RBC mass
  • Platelets (Thrombocytes): Clotting and bleeding control
• Red Blood Cell Indices:
  • MCV (Mean Corpuscular Volume): Size of RBC
  • MCHC (Mean Corpuscular Hemoglobin Concentration): Hemoglobin concentration
  • MCH (Mean Corpuscular Hemoglobin): Hemoglobin weight
  • RDW (Red Blood Cell Distribution Width): Abnormal cell size variability
  • MPV (Mean Platelet Volume): Platelet production index
• CBC Variability:
  • Affected by medications, body mass, dehydration, disease processes
• Differential White Blood Cell Count:
  • Granulocytes: Neutrophils, Basophils, Eosinophils
  • Agranulocytes: Lymphocytes, Monocytes
• WBC Lifespan: 13-20 days, excreted in stool
• WBC Function: Phagocytosis to fight infection

Major CBC Components Overview

• RBC: Decreased in anemia, increased in overproduction, high altitudes
• Hemoglobin: Normal range: 12-16 (females), 14-17 (males)
• Hematocrit: Percentage of RBCs, normal range: 42-52% (males), 36-48% (females)
• Platelets: Normal range: 140,000-400,000, vital for clotting
• WBC: Normal range: 5,000-10,000, elevated in infection/injury

Electrolyte and Metabolic Panels

• Electrolyte Panel: Assesses Sodium, Potassium, Chloride, Bicarbonate
• Comprehensive Metabolic Panel (CMP):
  • Includes Electrolyte Panel + Creatinine, Glucose, BUN, Calcium
  • Further includes Albumin, Alkaline Phosphatase, ALT, AST, Total Bilirubin, Total Protein
  • Requires fasting (10-12 hours)
  • Glucose: Normal fasting <100, diabetes >126 on 2 occasions
  • Calcium: Normal 8.8-10.4, low levels cause tetany, high levels cause cardiac issues
  • Albumin: Evaluates nutritional status
  • Sodium: Normal 136-145, affects water and acid-base balance
  • Potassium: Important for heart function, nerve/muscle function
  • Carbon Dioxide: Indicates blood alkalinity/acidity
  • Chloride: Part of acid-base balance
  • BUN (Blood Urea Nitrogen): Hydration indicator, affected by kidney function
  • Creatinine: Specific kidney function indicator, higher in males

Conclusion

• Refer to lab handbooks for detailed information.
• This lecture covers CBC and CMP, foundational for understanding lab work.