CBC Interpretation
Introduction to CBC
Definition and Components
A Complete Blood Count (CBC) is a laboratory test that evaluates the cellular components of blood. It provides crucial diagnostic and monitoring insights for various hematologic and systemic disorders. The major components include:
-
Red Blood Cell (RBC) Parameters
- RBC count
- Hemoglobin (Hgb)
- Hematocrit (Hct)
- RBC indices: MCV, MCH, MCHC, RDW
-
White Blood Cell (WBC) Parameters
- Total WBC count
- Differential WBC count (Neutrophils, Lymphocytes, Monocytes, Eosinophils, Basophils)
-
Platelet Parameters
- Platelet count
- Mean Platelet Volume (MPV)
- Platelet Distribution Width (PDW)
Indications and Clinical Uses
- Anemia Evaluation
- Infection and Inflammation (WBC abnormalities)
- Bone Marrow Disorders (Leukemia, Myelodysplastic Syndromes)
- Clotting and Bleeding Disorders (Thrombocytopenia, Thrombocytosis)
- Systemic Conditions (Liver disease, Renal failure, Autoimmune disorders)
 |
| CBC/CBP report |
Red Blood Cells (Erythrocytes) & Indices
1. RBC Count
- Measures the number of circulating red blood cells (millions per microliter of blood).
- Normal range:
- Men: 4.7–6.1 million/µL
- Women: 4.2–5.4 million/µL
- Children: 4.1–5.5 million/µL
- Elevated RBC count (Polycythemia): Dehydration, COPD, high altitude, polycythemia vera
- Low RBC count (Anemia): Blood loss, hemolysis, bone marrow failure
2. Hemoglobin (Hgb) & Hematocrit (Hct)
Hemoglobin (Hgb)
- The oxygen-carrying protein in RBCs
- Normal range:
- Men: 13.8–17.2 g/dL
- Women: 12.1–15.1 g/dL
Hematocrit (Hct):
- Measures the proportion of blood volume occupied by RBCs
- Normal range:
- Men: 42–52%
- Women: 37–47%
3. Red Cell Indices
Mean Corpuscular Volume (MCV) – Size of RBCs
- Normal: 80–100 fL
- Microcytic Anemia (MCV < 80 fL) → Iron deficiency, thalassemia
- Macrocytic Anemia (MCV > 100 fL) → B12/Folate deficiency, alcoholism
Mean Corpuscular Hemoglobin (MCH)
- Normal: 27–31 pg/cell
- Low: Hypochromic anemias
- High: Macrocytosis
Mean Corpuscular Hemoglobin Concentration (MCHC)
- Normal: 32–36 g/dL
- Low: Hypochromic anemias
- High: Spherocytosis
Red Cell Distribution Width (RDW) – RBC Size Variation
- Normal: 11.5–14.5%
- Increased RDW: Iron deficiency, mixed anemia types
4. Reticulocyte Count (Bone Marrow Activity Indicator)
- Normal: 0.5–2.5%
- High: Hemolysis, blood loss
- Low: Bone marrow suppression
White Blood Cells & Differential Count
1. Total WBC Count
- Normal: 4,000–11,000/µL
- Leukocytosis (>11,000/µL): Infection, leukemia, stress
- Leukopenia (<4,000/µL): Bone marrow suppression, viral infections
2. Differential WBC Count
- Neutrophils (55–70%) – Bacterial infections
- Lymphocytes (20–40%) – Viral infections, chronic conditions
- Monocytes (2–8%) – Chronic infections, TB
- Eosinophils (1–4%) – Allergies, parasitic infections
- Basophils (<1%) – Allergies, chronic inflammation
3. Neutrophil-to-Lymphocyte Ratio (NLR) in Disease Prognosis
- Higher NLR: Predicts worse prognosis in infections, cancer
Platelet Count & Function
1. Platelet Count
- Normal: 150,000–450,000/µL
- Thrombocytosis (>450,000/µL): Inflammation, malignancy
- Thrombocytopenia (<150,000/µL): ITP, DIC, leukemia
2. Platelet Indices
- Mean Platelet Volume (MPV): 7.5–11.5 fL
- Platelet Distribution Width (PDW): Increased in platelet disorders
Peripheral Blood Smear Correlation
- RBC Morphology: Target cells (Thalassemia), Schistocytes (DIC)
- WBC Abnormalities: Blast cells (Leukemia), Toxic granulation (Infection)
- Platelet Morphology: Giant platelets (ITP), Clumping
Interpretation in Specific Clinical Scenarios
1. Infection & Inflammation Patterns
- High neutrophils (Bacterial), High lymphocytes (Viral)
2. Anemia Workup
- Microcytic: Iron deficiency
- Normocytic: Chronic disease
- Macrocytic: B12/Folate deficiency
3. Bone Marrow Disorders
- Leukemia, Myelodysplasia
4. Platelet Disorders
- ITP, TTP, DIC
Conclusion & Further Workup
- Additional Tests: Bone marrow biopsy, Iron studies, Vitamin B12/Folate
- Role in Disease Monitoring: Chronic anemia, leukemia
No comments:
Post a Comment