Sample Clinical Cases for CBC Interpretation
Here are 5 real-world cases demonstrating different CBC abnormalities and how they guide diagnosis. Each case includes patient history, CBC findings, interpretation, and next steps.
🩸 Case 1: Microcytic Anemia (Iron Deficiency Anemia)
Patient Presentation
- Age/Sex: 42-year-old female
- Symptoms: Fatigue, dizziness, pallor, and heavy menstrual periods
- History: Vegetarian diet, no significant weight loss, no gastrointestinal symptoms
CBC Findings
| Parameter | Result | Normal Range |
|---|---|---|
| Hemoglobin (Hb) | 9.2 g/dL | 12-16 g/dL (F) |
| Hematocrit (Hct) | 30% | 36-46% |
| MCV | 72 fL | 80-100 fL |
| MCH | 24 pg | 27-33 pg |
| RDW | 17% | 11.5-14.5% |
| WBC | 6,200/µL | 4,000-11,000/µL |
| Platelets | 480,000/µL | 150,000-450,000/µL |
Interpretation & Diagnosis
🔹 Microcytic, hypochromic anemia with high RDW → Suggestive of Iron Deficiency Anemia
🔹 High platelets (reactive thrombocytosis) seen in chronic blood loss
Next Steps
✅ Order Iron Studies:
- Serum Ferritin ↓ (low iron stores)
- Serum Iron ↓ (low iron levels)
- TIBC ↑ (high iron-binding capacity)
✅ Confirm Underlying Cause:
- In women, heavy menstruation is common → Manage with iron supplementation
- In men/postmenopausal women, rule out GI bleeding (colonoscopy if necessary)
🩸 Case 2: Normocytic Anemia (Anemia of Chronic Disease – ACD)
Patient Presentation
- Age/Sex: 68-year-old male
- Symptoms: Fatigue, mild shortness of breath, joint pain
- History: Longstanding rheumatoid arthritis
CBC Findings
| Parameter | Result | Normal Range |
|---|---|---|
| Hemoglobin (Hb) | 10.8 g/dL | 13-17 g/dL (M) |
| Hematocrit (Hct) | 34% | 39-50% |
| MCV | 88 fL | 80-100 fL |
| MCH | 30 pg | 27-33 pg |
| RDW | 12% | 11.5-14.5% |
| WBC | 7,800/µL | 4,000-11,000/µL |
| Platelets | 420,000/µL | 150,000-450,000/µL |
Interpretation & Diagnosis
🔹 Normocytic anemia with normal RDW → Suggestive of Anemia of Chronic Disease (ACD)
🔹 Chronic inflammation leads to iron sequestration, preventing erythropoiesis
Next Steps
✅ Check Iron Studies:
- Ferritin ↑ (acute phase reactant)
- Serum Iron ↓ (iron trapped in macrophages)
- TIBC ↓ (low iron transport)
✅ Management:
- Treat underlying rheumatoid arthritis
- Consider erythropoietin-stimulating agents if severe
🩸 Case 3: Macrocytic Anemia (Vitamin B12 Deficiency)
Patient Presentation
- Age/Sex: 58-year-old male
- Symptoms: Fatigue, tingling in hands and feet, difficulty walking
- History: Chronic alcohol use, vegan diet
CBC Findings
| Parameter | Result | Normal Range |
|---|---|---|
| Hemoglobin (Hb) | 8.9 g/dL | 13-17 g/dL |
| Hematocrit (Hct) | 29% | 39-50% |
| MCV | 112 fL | 80-100 fL |
| MCH | 35 pg | 27-33 pg |
| RDW | 19% | 11.5-14.5% |
| WBC | 3,900/µL | 4,000-11,000/µL |
| Platelets | 120,000/µL | 150,000-450,000/µL |
Interpretation & Diagnosis
🔹 Macrocytic anemia with high RDW + Neurological symptoms → Suggestive of Vitamin B12 Deficiency
🔹 Mild leukopenia & thrombocytopenia → Suggests bone marrow suppression
Next Steps
✅ Check Vitamin Levels:
- Serum B12 ↓
- Serum Folate Normal
✅ Confirm Cause:
- Intrinsic factor antibodies (to rule out pernicious anemia)
- Schilling test (historical)
✅ Management:
- B12 injections (if neurological symptoms present)
- Address alcoholism and dietary deficiencies
🩸 Case 4: Leukocytosis (Acute Leukemia)
Patient Presentation
- Age/Sex: 27-year-old male
- Symptoms: Fatigue, fever, recurrent infections, bleeding gums
- History: No significant past medical history
CBC Findings
| Parameter | Result | Normal Range |
|---|---|---|
| Hemoglobin (Hb) | 7.5 g/dL | 13-17 g/dL |
| Hematocrit (Hct) | 23% | 39-50% |
| MCV | 88 fL | 80-100 fL |
| WBC | 85,000/µL | 4,000-11,000/µL |
| Platelets | 32,000/µL | 150,000-450,000/µL |
Interpretation & Diagnosis
🔹 Marked leukocytosis with anemia and thrombocytopenia → Highly suggestive of Acute Leukemia
🔹 Blasts likely present on peripheral blood smear
Next Steps
✅ Confirm Diagnosis with:
- Peripheral Smear → Look for blast cells
- Bone Marrow Biopsy → Needed for leukemia classification
- Flow Cytometry → Differentiates AML vs. ALL
✅ Management:
- Urgent hematology referral
- Induction chemotherapy
🩸 Case 5: Thrombocytopenia (Immune Thrombocytopenic Purpura – ITP)
Patient Presentation
- Age/Sex: 32-year-old female
- Symptoms: Easy bruising, petechiae, heavy menstrual bleeding
- History: Recent viral illness
CBC Findings
| Parameter | Result | Normal Range |
|---|---|---|
| Hemoglobin (Hb) | 12.2 g/dL | 12-16 g/dL |
| Hematocrit (Hct) | 38% | 36-46% |
| WBC | 6,400/µL | 4,000-11,000/µL |
| Platelets | 22,000/µL | 150,000-450,000/µL |
Interpretation & Diagnosis
🔹 Isolated thrombocytopenia → Suggestive of Immune Thrombocytopenic Purpura (ITP)
🔹 Post-viral autoantibody destruction of platelets
Next Steps
✅ Rule Out Secondary Causes:
- HIV, Hepatitis B/C
- Bone Marrow Biopsy (if atypical findings)
✅ Management:
- First-line: Corticosteroids
- If severe bleeding: IVIG or platelet transfusion