What is the diagnosis and recommended management for a patient with a white blood cell count of 9.85 ×10⁹/L, red blood cell count of 3.27 ×10¹²/L, hemoglobin 7.4 g/dL, hematocrit 25 %, mean corpuscular volume 76.5 fL, mean corpuscular hemoglobin 22.6 pg, and mean corpuscular hemoglobin concentration 29.6 g/dL?

Microcytic Anemia - Iron Deficiency Anemia

This patient has severe microcytic anemia (Hb 7.4 g/dL, MCV 76.5 fL) consistent with iron deficiency anemia and requires immediate serum ferritin testing to confirm the diagnosis, followed by comprehensive gastrointestinal evaluation to identify the source of blood loss, which is the most common cause in adults. 1

Diagnosis

The laboratory values reveal:

• Severe anemia: Hemoglobin 7.4 g/dL (well below normal range for either sex)
• Microcytosis: MCV 76.5 fL (below normal range of ~80-100 fL)
• Hypochromia: MCH 22.6 pg and MCHC 29.6 g/dL (both reduced)
• Normal WBC: 9.85 ×10⁹/L (rules out concurrent infection or hematologic malignancy)

Microcytosis with low MCH and MCHC is characteristic of iron deficiency, though thalassemia and anemia of chronic disease must be considered in the differential 1.

Confirm Iron Deficiency

Serum ferritin is the most powerful test for iron deficiency 1:

• Ferritin <12 μg/dL is diagnostic of iron deficiency
• Ferritin 12-100 μg/dL may still indicate iron deficiency if concurrent inflammation, malignancy, or liver disease is present
• Ferritin >100 μg/dL essentially excludes iron deficiency

If ferritin is equivocal (12-100 μg/dL), consider:

• Transferrin saturation <30% supports iron deficiency 1
• Therapeutic trial of oral iron for 3 weeks (diagnostic and therapeutic)
• Red cell distribution width (RDW) may be elevated, especially if combined deficiency exists 1

Rule Out Alternative Causes

Critical pitfall: Do not assume thalassemia without laboratory confirmation, even in high-risk ethnic groups 1. In thalassemia, the RBC count is typically elevated (not 3.27 as in this case), which helps distinguish it from iron deficiency.

Management Algorithm

1. Immediate Assessment (Based on Patient Demographics)

For men and post-menopausal women: Gastrointestinal blood loss is the most common cause 1. Asymptomatic gastric and colonic carcinoma may present with iron deficiency anemia, making exclusion of malignancy the prime concern 1.

For pre-menopausal women: Menstrual blood loss is most common, but GI evaluation is still required if dietary history and menstrual history don't fully explain the severity.

2. Required Investigations

In the absence of overt blood loss or obvious cause, all patients should undergo 1:

• Upper GI endoscopy with small bowel biopsies (to exclude coeliac disease, which causes 2-3% of iron deficiency anemia cases) 1
• Colonoscopy or barium enema (to exclude colonic cancer/polyps, angiodysplasia)

The order of investigations depends on local availability and patient age—in elderly patients, colonic investigation is likely more productive 1.

Upper GI endoscopy reveals a cause in 30-50% of patients 1.

3. History and Physical Examination - Key Details

Document specifically:

• Dietary history: Iron-deficient diet (though borderline deficient diets are common and should not preclude full GI investigation) 1
• NSAID/aspirin use: Stop if possible, but their use should not deter investigation 1
• GI symptoms: Upper or lower (though symptoms rarely correlate with findings) 1
• Family history: Thalassemia, sideroblastic anemia, telangiectasia, bleeding disorders 1
• For women: Menstrual history

4. Treatment

Once iron deficiency is confirmed:

First-line: Oral iron supplementation 2

• Recent evidence supports intermittent dosing as effective as daily dosing with fewer side effects 2

Second-line: Intravenous iron for patients who:

• Cannot tolerate oral iron
• Cannot absorb oral iron (e.g., coeliac disease, gastric surgery)
• Do not respond to oral iron
• Contemporary IV formulations have rare allergic reactions 2

5. Common Pitfalls

• Do not assume dietary deficiency alone explains this degree of anemia—full GI investigation is still required 1
• Do not let anticoagulant use deter investigation 1
• Mild anemia is not less indicative of important disease than severe anemia—investigate regardless of severity 1
• Do not presume haemoglobinopathy without laboratory confirmation 1

6. Prognosis

Treatment of the underlying cause will cure the anemia, but even when no cause is detected, the long-term outlook is good 1.