What is the cause of this patient's elevated hemoglobin and hematocrit levels, despite symptoms suggestive of anemia of chronic disease?

Elevated Hemoglobin and Hematocrit in a Pre-Menopausal Woman

This patient does not have anemia—she has polycythemia (elevated hemoglobin 17.0 g/dL, hematocrit 51.2%, RBC 5.42) with concurrent low folate and low-normal B12, which requires investigation for secondary causes of erythrocytosis rather than treatment for anemia of chronic disease.

Key Laboratory Findings Analysis

Polycythemia, Not Anemia

• Hemoglobin is 17.0 g/dL (reference 11.1-15.9)—significantly elevated, not decreased 1
• Hematocrit is 51.2% (reference 34.0-46.6%)—markedly elevated 1
• RBC count is 5.42 (reference 3.77-5.28)—elevated 1
• The normal range for hemoglobin in women is <15.9 g/dL; this patient exceeds this by >1 g/dL 2

Iron Studies Are Normal

• Iron saturation 34% is normal (>20% excludes functional iron deficiency) 2
• TIBC 268 μg/dL is within normal range (250-450) 2
• Serum iron 92 μg/dL is normal (27-159) 2
• These values exclude both iron deficiency and anemia of chronic disease 2

Nutritional Deficiencies Present

• Folate 2.0 ng/mL is low (though specific reference range not provided, marked as "L") 1
• Vitamin B12 193 pg/mL is low-normal (marked as "L"), which may indicate early deficiency 1
• MCV 95 fL is high-normal, which can mask combined deficiency states where microcytosis from one deficiency is offset by macrocytosis from another 2

Clinical Context: Why This Matters

Chronic Disease Does Not Cause Polycythemia

• Anemia of chronic disease (from COPD, fibromyalgia) causes LOW hemoglobin with low serum iron, low transferrin saturation (<20%), and elevated ferritin (>100 μg/L) 2, 3
• This patient has the opposite: elevated hemoglobin with normal iron parameters 3, 4
• Inflammatory cytokines in chronic disease suppress erythropoietin production and inhibit erythropoiesis, leading to anemia, not polycythemia 3, 5

Secondary Polycythemia Differential

This patient requires evaluation for:

• Chronic hypoxemia from COPD (most likely given her history)—chronic low oxygen stimulates erythropoietin production 1
• Sleep apnea (common in women with obesity-related conditions)
• Smoking history (not documented but should be assessed)
• Renal pathology (though creatinine not provided, renal disease can cause inappropriate erythropoietin secretion) 1

The Folate/B12 Deficiency Paradox

• Combined folate and B12 deficiency with iron sufficiency can result in normal MCV because macrocytic tendency from vitamin deficiency is balanced 2
• RDW 13.0% is normal, which argues against significant combined deficiency causing red cell size variation 2
• The low folate/B12 is likely incidental to the polycythemia and related to poor dietary intake or malabsorption 1

Recommended Diagnostic Approach

Immediate Workup

1. Obtain arterial blood gas or pulse oximetry to assess for chronic hypoxemia from COPD 1
2. Measure serum erythropoietin level—elevated in secondary polycythemia, low in primary polycythemia vera 1
3. Complete smoking history and carbon monoxide level if actively smoking
4. Sleep study if clinical suspicion for sleep apnea

Nutritional Assessment

• Supplement folate (400-1000 mcg daily) and B12 (1000 mcg daily) given documented deficiencies 1, 4
• Recheck levels in 8-12 weeks to ensure repletion 1
• These deficiencies will not resolve the polycythemia but should be corrected independently 4

Hematology Referral Considerations

• If erythropoietin is inappropriately low with elevated hemoglobin, consider primary polycythemia vera and refer to hematology 1
• If no secondary cause identified, bone marrow evaluation may be needed 1

Common Pitfalls to Avoid

• Do not assume chronic disease causes all hematologic abnormalities—COPD causes polycythemia through hypoxemia, not anemia 3, 5
• Do not treat with iron—iron parameters are normal and iron supplementation in polycythemia is contraindicated 2, 5
• Do not ignore the elevated hemoglobin thinking it's "good" in someone with chronic disease—polycythemia increases blood viscosity and thrombotic risk 1
• Do not attribute everything to nutritional deficiency—the folate/B12 deficiency is real but unrelated to the polycythemia mechanism 1

Management Priority

The primary concern is identifying and managing the cause of polycythemia (likely COPD-related hypoxemia), while concurrently correcting the nutritional deficiencies with folate and B12 supplementation. 1, 4 The patient's chronic diseases predispose to anemia of chronic disease, but she paradoxically has the opposite problem, indicating a dominant secondary erythrocytosis process that overrides any inflammatory suppression of erythropoiesis.