Management of Elevated Hemoglobin in a 15-Year-Old Female with Normal Iron Stores
This 15-year-old female does not have anemia or iron deficiency and requires evaluation for polycythemia, not iron deficiency anemia management. The hemoglobin of 156 g/L (15.6 g/dL) is elevated for a female, and the iron saturation of 0.86 (86%) is markedly elevated, indicating iron overload rather than deficiency 1.
Key Laboratory Interpretation
- Hemoglobin 156 g/L: This exceeds the WHO threshold for anemia in females (>120 g/L) and approaches polycythemia range (>160 g/L in females) 1
- RDW 11.2%: Normal, indicating uniform red cell size
- Iron 54.3 with saturation 0.86 (86%): Markedly elevated transferrin saturation (normal <45%) suggests either iron overload or a myeloproliferative disorder 1
Diagnostic Approach
Primary Consideration: Rule Out Polycythemia Vera
JAK2 mutation testing should be performed as the first-line investigation given the elevated hemoglobin in conjunction with other potential features of a myeloproliferative neoplasm 2, 3. The JAKPOT prediction rule suggests testing when patients have elevated RBC count, platelets >350×10⁹/L, or neutrophils >6.2×10⁹/L 2.
Complete blood count with differential is essential to evaluate for:
- Elevated platelet count (>350×10⁹/L) 2
- Elevated white blood cell count, particularly neutrophils (>6.2×10⁹/L) 2
- Red blood cell count >6.45×10¹²/L 2
Secondary Considerations
If JAK2 mutation is negative, evaluate for secondary causes of erythrocytosis 4, 3:
- Serum erythropoietin level (will be low in polycythemia vera, elevated in secondary causes) 3
- Oxygen saturation and pulmonary function
- Renal ultrasound to exclude renal tumors
- Sleep history for obstructive sleep apnea 3
Hemochromatosis screening should be considered given the markedly elevated iron saturation 1:
- HFE gene mutation testing (C282Y and H63D) 1
- Serum ferritin level 1
- Hepatic iron concentration if genetic testing is positive and ferritin >1,000 ng/mL 1
Critical Pitfalls to Avoid
Do not treat this as iron deficiency anemia - the iron studies clearly show iron overload, not deficiency 1. Iron supplementation would be contraindicated and potentially harmful 1.
Do not dismiss elevated hemoglobin in a young female - while less common than in males, polycythemia vera can present in adolescents and young adults, and early diagnosis is crucial to prevent thrombotic complications 3.
Recognize that normal hematocrit can mask polycythemia - in some cases, increased plasma volume can result in normal hemoglobin/hematocrit despite elevated red cell mass (inapparent polycythemia), though this patient's hemoglobin is already elevated 5.
Immediate Management
Refer to hematology for definitive evaluation if JAK2 mutation is positive or if clinical suspicion for myeloproliferative disorder remains high despite negative initial testing 4, 3. Bone marrow biopsy may be required for definitive diagnosis 3.
Avoid iron supplementation and vitamin C supplements until the diagnosis is clarified, as these could exacerbate iron overload if hemochromatosis is present 1.
Assess thrombotic risk factors including smoking, oral contraceptive use, and family history of thrombosis, as polycythemia vera significantly increases thrombotic risk 3.