Hemoglobin
Hemoglobin is the oxygen-carrying protein in red blood cells. Population levels are consistently higher in males than females, with a gradual decline in both sexes after age 60.
Unit: g/dL · 12 slices · age and sex · 1 source
Filed under panels: Complete Blood Count · topics: Hematology
Hemoglobin concentration reflects the oxygen-carrying capacity of blood. It is measured directly on whole blood as part of the complete blood count. Values differ substantially by sex due to the effects of testosterone on erythropoiesis and menstrual iron losses in females. Age-related changes include a decline in older adults related to reduced erythropoietin production and chronic disease prevalence.
Population Distribution
Browse by Demographic
| Age (years) | male (g/dL) | female (g/dL) |
|---|---|---|
| 20-29 | 13.6–16.9 (15.2) | 11.5–15 (13.4) |
| 30-39 | 13.4–16.8 (15.1) | 11.1–15 (13.3) |
| 40-49 | 13.5–16.8 (15.1) | 10.5–15.2 (13.5) |
| 50-59 | 13.3–16.8 (15.3) | 11.5–15.2 (13.7) |
| 60-69 | 12.3–17 (14.9) | 11.7–15.4 (13.6) |
| 70+ | 11.6–16.7 (14.5) | 11.4–15.4 (13.5) |
Frequently Asked Questions
Why do males have higher hemoglobin than females?
Testosterone stimulates erythropoiesis (red blood cell production), and males do not experience menstrual blood loss. Both factors contribute to higher hemoglobin concentrations in males throughout adulthood.
Why does hemoglobin decline with age?
Kidney function declines gradually with age, reducing erythropoietin production. The prevalence of chronic conditions that suppress red blood cell production also increases. Both contribute to lower population hemoglobin levels in older age groups.
Why are these population percentiles, not clinical reference ranges?
Clinical reference ranges are derived from a selected population of presumed-healthy individuals and are designed to flag potential pathology. Population percentiles from NHANES describe the distribution in the general US population, including individuals with subclinical conditions. Both are useful and answer different questions.