What does a hemoglobin concentration of 17 g/dL indicate?

Hemoglobin 17 g/dL: Clinical Interpretation

A hemoglobin of 17 g/dL falls within the normal range for adult males (upper limit ~17.0 g/dL at 97.5th percentile) but is elevated for adult females and warrants clinical evaluation to exclude polycythemia vera or secondary causes of erythrocytosis. 1, 2

Normal Reference Ranges by Sex

• Adult males: Normal hemoglobin ranges up to approximately 17.0 g/dL, with anemia defined as <13.5 g/dL 3
• Adult females: Normal hemoglobin ranges up to approximately 15.5 g/dL, with anemia defined as <12.0 g/dL 3
• Postmenopausal females: Average hemoglobin 15.5 ± 2.0 g/dL 4

When to Investigate Further

For Adult Males with Hb 17 g/dL

This value sits at the upper limit of normal and requires evaluation if accompanied by a sustained increase of ≥2 g/dL from the patient's previous baseline, as this meets WHO criteria for possible polycythemia vera. 3, 2

• Order complete blood count with differential, reticulocyte count, serum ferritin, transferrin saturation, and JAK2 mutation testing if there is documented baseline increase or clinical features suggesting myeloproliferative disease 1, 4
• Consider secondary causes including smoking (increases Hb by 0.3-1.0 g/dL), altitude (increases Hb by 0.2-4.5 g/dL depending on elevation), sleep apnea, COPD, or testosterone use 1, 4

For Adult Females with Hb 17 g/dL

This value is clearly elevated and requires immediate investigation, as it exceeds the normal range and approaches the WHO diagnostic threshold for polycythemia vera (≥16.5 g/dL). 3, 2

• Obtain JAK2 V617F mutation testing immediately, as this is found in >90% of polycythemia vera cases 3, 4
• Measure serum erythropoietin level to differentiate primary (low EPO) from secondary (normal/high EPO) causes 3, 2
• Evaluate for iron deficiency, which can mask polycythemia vera by lowering hemoglobin below diagnostic thresholds 2, 4

Diagnostic Algorithm for Polycythemia Vera

WHO criteria require BOTH major criteria plus ≥1 minor criterion, OR the first major criterion plus ≥2 minor criteria: 3, 2

Major Criteria

1. Hemoglobin ≥18.5 g/dL (men) or ≥16.5 g/dL (women), OR hemoglobin ≥17 g/dL (men) or ≥15 g/dL (women) with documented sustained increase of ≥2 g/dL from baseline 3, 2
2. Presence of JAK2 V617F or JAK2 exon 12 mutation 3, 2

Minor Criteria

1. Bone marrow biopsy showing hypercellularity with trilineage growth (panmyelosis) 3, 2
2. Serum erythropoietin level below normal reference range 3, 2
3. Endogenous erythroid colony formation in vitro 3, 2

Secondary Causes to Exclude

Before diagnosing primary polycythemia vera, systematically evaluate for secondary causes: 4

• Hypoxic causes: Obstructive sleep apnea, COPD, cyanotic congenital heart disease, high altitude residence 4
• Non-hypoxic causes: Renal cell carcinoma, hepatocellular carcinoma, testosterone therapy, erythropoietin-producing tumors 4
• Relative polycythemia: Dehydration, diuretic use, stress polycythemia (Gaisböck syndrome) 4

Management Considerations

If Polycythemia Vera is Confirmed

Maintain hematocrit strictly below 45% through therapeutic phlebotomy to reduce thrombotic risk, as demonstrated by the CYTO-PV trial showing significant reduction in thrombotic events (2.7% vs 9.8%, P=0.007). 4

• Initiate low-dose aspirin (81-100 mg daily) as second cornerstone of therapy for thrombosis prevention 4
• Refer to hematology for ongoing management and consideration of cytoreductive therapy 4

If Secondary Erythrocytosis is Identified

Treat the underlying condition rather than performing phlebotomy, as the elevated hemoglobin represents a compensatory physiological response. 4

• Smoking cessation for smoker's polycythemia 4
• CPAP therapy for obstructive sleep apnea 4
• Dose adjustment or discontinuation of testosterone if causative 4
• Therapeutic phlebotomy is indicated ONLY when hemoglobin >20 g/dL and hematocrit >65% with symptoms of hyperviscosity 4

Critical Pitfalls to Avoid

• Never perform aggressive phlebotomy without adequate volume replacement, as this increases hemoconcentration and stroke risk 4
• Do not overlook coexisting iron deficiency, which can mask polycythemia vera and requires cautious supplementation with close monitoring 2, 4
• Avoid repeated routine phlebotomies in secondary erythrocytosis, as this causes iron depletion, decreased oxygen-carrying capacity, and paradoxically increases stroke risk 4
• Do not use standard polycythemia vera diagnostic thresholds at high altitude without adjustment, as physiologic adaptation can increase hemoglobin by 0.2-4.5 g/dL depending on elevation 4, 5