📘 Chapter 13: Pathology of Blood and Urine
🩸 Pathology of Blood
The study of diseases related to blood is called “Pathology of Blood”. It involves examining the quality, quantity, function, and abnormalities of various blood components.
🔍 1. Hematological Tests
These are key diagnostic tests related to blood:
✅ (i) Hemoglobin Test (Hb Test)
This test measures the hemoglobin level in the body.
Normal Range:
- Male: 13.8 – 16 g/dl
- Female: 11.6 – 15 g/dl
- Children: 11.2 – 14.5 g/dl
Significance:
- Low Hb: Anemia, Leukemia (blood cancer)
- High Hb: Increased RBC concentration (Polycythemia)
✅ (ii) RBC Count (Red Blood Cells Count)
RBCs transport oxygen (O₂) and carbon dioxide (CO₂) in the body.
Normal Range:
- Male: 4.5 – 5.5 million/mm³
- Female: 3.5 – 5.5 million/mm³
- Children: 4.0 – 5.5 million/mm³
Significance:
- Low RBCs: Anemia, Leukemia
- High RBCs: Polycythemia
✅ (iii) Platelet Count
Platelets help in blood clotting and prevent excessive bleeding.
Normal Range: 1.5 lakh – 4.5 lakh / mm³ (150,000 – 450,000 / mm³)
Low Platelets:
- Dengue, Chikungunya, Leukemia, HIV, Pregnancy
High Platelets:
- Cancer, Iron deficiency, Bone marrow disorders
✅ (iv) Blood Sugar Levels
| Condition | Normal Range (mg/dl) |
|---|---|
| Fasting | 70 – 99 |
| After 2 hours (PP) | Less than 140 |
| Random | 110 – 140 |
✅ (v) Uric Acid Test
Normal Range: 2 – 6 mg/dl
High Uric Acid indicates:
- Gout
- Renal (Kidney) Failure
🧬 Lymphocytes and Platelets – Role in Health and Disease
🔹 Lymphocytes:
Lymphocytes are a type of WBC (White Blood Cell) involved in the immune system.
Types of Lymphocytes:
- B-Lymphocytes (B-cells): Produce antibodies against bacteria and viruses
- T-Lymphocytes (T-cells): Destroy infected and cancerous cells
Normal Count:
- B-Cells: 100–600 cells/mm³
- T-Cells: 500–1200 cells/mm³
High Lymphocyte Count (Lymphocytosis):
- Infections
- Autoimmune disorders
- Cancer
🔹 Platelets (Thrombocytes):
- Small, colorless cells involved in blood clotting
- Prevent bleeding and aid in wound healing
Key Functions:
- Vasoconstriction: Shrinks damaged blood vessels
- Coagulation: Helps in clot formation
- Fibrinolysis: Breaks down clots after healing
Abnormal Count:
- Low Platelets (Thrombocytopenia): Leads to poor clotting and internal bleeding
- High Platelets (Thrombocythemia): Risk of clot formation and stroke
🧪 Abnormalities in RBCs
🔹 Variation in Size (Anisocytosis):
- Normal size: 6–8 microns
- If RBCs vary in size, it is called Anisocytosis
🔹 Variation in Shape (Poikilocytosis):
- Normal RBCs are biconcave discs
- Abnormal shapes include: sickle-shaped, oval-shaped, etc.
🔹 Variation in Color:
- Color changes are due to hemoglobin level
- Low Hb = pale RBCs
- High Hb = dark red RBCs
⚠️ Disorders of Erythrocytes (RBCs):
- Anemia
- Iron Deficiency Anemia
- Megaloblastic Anemia (Vitamin B12/Folate deficiency)
- Hemolytic Anemia (destruction of RBCs)
- Red Cell Enzyme Deficiency
💧 Pathology of Urine
Urine is a liquid waste product formed by the kidneys and excreted through the urethra, a process called micturition.
🔹 Normal Constituents of Urine:
| Substance | Approximate Amount (per liter) |
|---|---|
| Water | 95% |
| Urea | 9.3 g |
| Chloride | 1.87 g |
| Sodium | 1.17 g |
| Potassium | 0.75 g |
| Creatinine | 0.67 g |
These are essential to assess kidney function, hydration status, and detect infections or metabolic issues.