Is a hemoglobin consistently ranging from 15.8 to 17 g/dL considered persistently elevated in a female patient?

Hemoglobin 15.8-17 g/dL in Females: Not Persistently Elevated

A hemoglobin consistently ranging from 15.8 to 17 g/dL in a female patient is NOT considered normal—this represents persistently elevated hemoglobin that warrants evaluation for polycythemia vera or secondary causes of erythrocytosis.

Normal Hemoglobin Thresholds for Females

• The World Health Organization and multiple clinical guidelines define the upper limit of normal hemoglobin in women as <16.5 g/dL 1
• The WHO specifically defines anemia as hemoglobin <12 g/dL in women, establishing the normal range implicitly between 12-16.5 g/dL 1
• Values of 15.8-17 g/dL consistently exceed the 99th percentile for females and meet criteria for further investigation 1

Clinical Significance of This Range

This hemoglobin range (15.8-17 g/dL) meets the major criterion for polycythemia vera evaluation in females, as the WHO diagnostic criteria define elevated hemoglobin as ≥16.5 g/dL in women 1. Your patient's values consistently exceed this threshold.

Key Diagnostic Considerations

• Polycythemia vera workup is indicated: The revised WHO criteria require hemoglobin ≥16.5 g/dL in women as a major criterion, which your patient meets 1
• JAK2 mutation testing should be performed: Approximately 95% of polycythemia vera cases carry the JAK2V617F mutation 1
• Exclude secondary causes: Before diagnosing primary polycythemia, rule out hypoxia, high-altitude residence, sleep apnea, chronic lung disease, renal tumors, or inappropriate erythropoietin production 1

Diagnostic Algorithm

1. Confirm persistent elevation: Document hemoglobin ≥16.5 g/dL on at least two separate occasions 1

2. Order JAK2V617F mutation testing: This is now a major diagnostic criterion for polycythemia vera 1

3. Measure serum erythropoietin level: Low levels support polycythemia vera; elevated levels suggest secondary erythrocytosis 1

4. Consider bone marrow biopsy if JAK2 positive: Look for hypercellularity with trilineage growth (panmyelosis) with prominent erythroid, granulocytic, and megakaryocytic proliferation 1

5. Evaluate for secondary causes if JAK2 negative: Check arterial oxygen saturation, carboxyhemoglobin level, abdominal imaging for renal masses, and sleep study if clinically indicated 1

Common Pitfalls to Avoid

• Do not dismiss elevated hemoglobin as "high normal": Values consistently ≥16.5 g/dL in women require investigation regardless of whether the patient is symptomatic 1
• Iron deficiency can mask polycythemia vera: If ferritin is low, the WHO criteria require demonstrating that hemoglobin remains elevated after iron replacement therapy before excluding polycythemia vera 1
• Relative polycythemia (Gaisböck syndrome) must be excluded: Some patients have reduced plasma volume rather than true erythrocytosis, though this still represents pathology requiring evaluation 2

When to Refer to Hematology

Immediate hematology referral is warranted when hemoglobin persistently exceeds 16.5 g/dL in women, particularly if accompanied by:

• Splenomegaly 1
• Thrombocytosis (platelets >400 × 10⁹/L) 1
• Leukocytosis (WBC >12 × 10⁹/L) 1
• Pruritus after bathing 1
• History of thrombotic events 1