Normocytic Hypochromic Anemia with Lymphopenia: Iron Deficiency Anemia
This 47-year-old man has iron deficiency anemia (IDA) despite a normal MCV, and requires immediate iron studies (ferritin, transferrin saturation) followed by gastrointestinal evaluation to identify the source of blood loss.
Why This is Iron Deficiency Anemia
The laboratory pattern is classic for early or evolving IDA:
- Low MCH (25.4) and low MCHC (30.6) indicate hypochromia—the hallmark of iron deficiency 1
- Normal MCV (83.2) does not exclude IDA; microcytosis develops later in the disease progression
- MCH is actually more sensitive than MCV for detecting iron deficiency and decreases earlier in the disease course 1
- The combination of normocytic anemia with hypochromia (low MCH/MCHC) represents the transition phase before frank microcytosis develops
The isolated lymphopenia (783) is likely incidental and not the primary pathology driving this anemia picture.
Immediate Diagnostic Workup
Order these iron studies now:
- Serum ferritin (most specific test; <30 μg/L confirms IDA, <45 μg/L highly suggestive) 2, 1
- Transferrin saturation (confirmatory, especially if ferritin equivocal)
- Reticulocyte count (assess bone marrow response)
Critical caveat: If the patient has any inflammatory condition, ferritin may be falsely normal up to 100 μg/L. In this scenario, transferrin saturation or soluble transferrin receptor becomes essential 2.
Source Identification (Mandatory in Adult Men)
In a 47-year-old man, IDA is gastrointestinal blood loss until proven otherwise 1. This age and sex combination demands:
Bidirectional endoscopy (upper and lower GI):
- Evaluate for occult GI malignancy (colorectal cancer, gastric cancer)
- Assess for peptic ulcer disease, gastritis, angiodysplasia
- Test for Helicobacter pylori infection 2
- Consider celiac disease screening (tissue transglutaminase antibody)
Additional history to obtain:
- NSAID use (peptic ulcer disease)
- Aspirin or anticoagulant use
- Any overt GI bleeding (melena, hematochezia, hematemesis)
- Dietary iron intake assessment
- Family history of GI malignancy or celiac disease
Iron Replacement Strategy
Start oral iron immediately while awaiting endoscopy (treatment can be both diagnostic and therapeutic):
- Ferrous sulfate, ferrous fumarate, or ferrous gluconate (least expensive, equally effective) 2
- Dosing: Take on empty stomach if tolerated; with meals if GI side effects occur
- Add 500 mg vitamin C to enhance absorption 2
- Expect Hgb rise ≥10 g/L within 2 weeks if truly iron deficient 1—this response confirms the diagnosis even if iron studies were equivocal
Switch to IV iron if:
- Intolerable GI side effects (nausea, constipation, abdominal pain)
- No response to oral iron after 4-6 weeks
- Malabsorption suspected (celiac disease, inflammatory bowel disease)
- Severe anemia requiring rapid correction 2
The Lymphopenia Issue
The absolute lymphocyte count of 783 (normal ~1000-4800) with normal WBC (8.9) is mild and likely secondary:
- Chronic illness/anemia can cause mild lymphopenia
- Nutritional deficiencies (iron, B12, folate) affect lymphocyte production
- Monitor with repeat CBC after iron repletion
- Only pursue lymphopenia workup if it persists after anemia correction or worsens
Common Pitfalls to Avoid
- Don't dismiss IDA because MCV is normal—hypochromia (low MCH/MCHC) precedes microcytosis 1
- Don't skip GI evaluation in adult men—this is the highest-risk group for GI malignancy
- Don't accept "normal" ferritin at face value—inflammation can mask iron deficiency up to ferritin 100 μg/L 2
- Don't get distracted by the lymphopenia—address the anemia first, reassess lymphocytes after treatment