Assessment of Hematocrit 46.5%
A hematocrit of 46.5% is within the normal physiological range for most adults and does not require treatment. This value falls well below the thresholds that define true erythrocytosis and does not meet criteria for therapeutic intervention.
Normal Reference Ranges
For adult males and post-menopausal females, the normal hematocrit is 47 ± 6% (range approximately 41-53%), while menstruating females have a normal hematocrit of 41 ± 5% (range approximately 36-46%). 1
The physiological range of hematocrit in healthy adults extends from approximately 36-48%, with values varying by sex, age, and physiological factors. 1
True erythrocytosis requiring diagnostic evaluation is defined by hematocrit >55% in men or >49.5% in women, making your value of 46.5% clearly below these thresholds. 1
Clinical Significance of This Value
A hematocrit of 46.5% represents a normal physiological state and does not indicate polycythemia vera or secondary erythrocytosis. 1
Within-subject biological variation of hematocrit is approximately 3%, meaning natural fluctuations can cause a relative change of approximately 12% between measurements taken days to months apart. 2
Seasonal variation can lower population mean hematocrit by approximately 3% in summer compared to winter due to hemodilution in warm weather, with some studies showing up to 7% variation. 2
When Intervention Would Be Indicated
Therapeutic phlebotomy is indicated only when hemoglobin exceeds 20 g/dL AND hematocrit exceeds 65%, with documented symptoms of hyperviscosity after excluding dehydration. 1, 3
For confirmed polycythemia vera specifically:
The National Comprehensive Cancer Network recommends maintaining hematocrit strictly below 45% through therapeutic phlebotomy to reduce thrombotic risk, based on the CYTO-PV trial showing reduced cardiovascular death and major thrombosis (2.7% vs 9.8%, P=0.007). 1, 3
A slightly lower target of approximately 42% is recommended for women and African Americans due to physiological differences in baseline hematocrit values. 3
Common Pitfalls to Avoid
Do not perform routine phlebotomy in patients with hematocrit values in the normal range, as this causes iron depletion, decreased oxygen-carrying capacity, and paradoxically increases stroke risk. 1
Do not confuse relative polycythemia (from dehydration or plasma volume depletion) with true erythrocytosis—hydration status should always be assessed before pursuing extensive workup. 1
Hemoglobin is more reliable than hematocrit for monitoring, as hematocrit can falsely increase by 2-4% with prolonged sample storage while hemoglobin remains stable. 1
Recommendation
No treatment or further diagnostic workup is needed for a hematocrit of 46.5% in an asymptomatic individual. This value represents normal physiology and falls well within expected ranges for healthy adults.