What are the implications and recommended next steps for a 54-year-old female with hemoglobin (Hb) of 15.8 and hematocrit (Hct) of 47.1?

Evaluation of Elevated Hemoglobin and Hematocrit in a 54-Year-Old Female

This 54-year-old female has borderline elevated hemoglobin (15.8 g/dL) and hematocrit (47.1%), which fall within the normal physiological range for healthy women but warrant confirmation with repeat testing and clinical correlation to exclude early erythrocytosis or secondary causes. 1

Understanding the Laboratory Values

Normal Reference Ranges:

• For adult females, the typical hemoglobin range is 14.0 ± 2.0 g/dL and hematocrit is 41 ± 5% 2
• The World Health Organization defines anemia in women ≥15 years as hemoglobin <12 g/dL 2
• This patient's values (Hb 15.8 g/dL, Hct 47.1%) are at the upper end of normal but do not meet criteria for erythrocytosis 1

Erythrocytosis Thresholds:

• True erythrocytosis in women is defined as hemoglobin >16.5 g/dL or hematocrit >49.5% 1
• This patient falls just below these thresholds 1

Recommended Initial Approach

Confirm the Values:

• Repeat hemoglobin and hematocrit measurements, as a single measurement is not reliable for establishing a diagnosis 1
• If values remain stable and below erythrocytosis thresholds, serial monitoring every 3-6 months is appropriate 1

If Values Are Persistently Elevated or Rising:

Complete the initial laboratory workup: 1

• Complete blood count with red cell indices (MCV, MCH, MCHC, RDW)
• Reticulocyte count
• Serum ferritin and transferrin saturation
• C-reactive protein (CRP)

Key Diagnostic Considerations:

1. Relative vs. Absolute Polycythemia:

   • Assess hydration status, as dehydration can cause hemoconcentration and falsely elevated values 1
   • Diuretic use can cause relative polycythemia through plasma volume depletion 1

2. Secondary Causes to Evaluate: 1

   • Smoking history: Carbon monoxide exposure stimulates erythropoietin production causing "smoker's polycythemia" 1
   • Sleep apnea: Nocturnal hypoxemia drives erythropoietin production 1
   • Chronic lung disease: COPD or other pulmonary conditions causing chronic hypoxia 1
   • Medications: Testosterone therapy (even topical) can cause erythrocytosis 1

3. Primary Polycythemia Vera (if values exceed thresholds):

   • JAK2 mutation testing (exon 14 and exon 12) should be performed if hemoglobin exceeds 16.5 g/dL or hematocrit exceeds 49.5% 1
   • Up to 97% of polycythemia vera cases carry JAK2 mutations 1

Age-Related Considerations

Important caveat: While some sources suggest hemoglobin may decline slightly with age in men, hemoglobin concentrations in women remain stable between ages 20-80 years 2

• Anemia is not a normal consequence of aging and should always be investigated 2
• The lowest acceptable hemoglobin level in women is 11.0 g/dL, regardless of age 3

When to Refer to Hematology

Immediate referral is indicated if: 1

• JAK2 mutation is positive
• Hemoglobin >20 g/dL or hematocrit >65% with symptoms of hyperviscosity
• Unexplained splenomegaly
• Associated thrombocytosis or leukocytosis suggesting myeloproliferative disorder

Common Pitfalls to Avoid

• Do not assume these values are "normal for her" without excluding secondary causes 1
• Do not perform therapeutic phlebotomy unless hemoglobin exceeds 20 g/dL and hematocrit exceeds 65% with hyperviscosity symptoms 1
• Do not overlook coexisting iron deficiency, which can mask the degree of erythrocytosis 1
• Hemoglobin is more reliable than hematocrit for monitoring, as hematocrit can falsely increase by 2-4% with prolonged sample storage 2

Practical Management Algorithm

For this specific patient (Hb 15.8, Hct 47.1):

1. Repeat measurements in 1-2 months 1
2. If stable and <16.5 g/dL hemoglobin: Monitor every 6 months 1
3. If rising or exceeds 16.5 g/dL: Complete full workup including JAK2 testing 1
4. Evaluate for secondary causes: smoking, sleep apnea, medications, chronic lung disease 1
5. If all workup negative and values stable: Continue observation with annual monitoring 1