Anemia Definition in Adult Males
Anemia in adult males is defined as a hemoglobin level below 13.5 g/dL, and this threshold should trigger diagnostic evaluation and workup for underlying causes. 1
Diagnostic Threshold
- Hemoglobin <13.5 g/dL in adult males ≥18 years of age constitutes anemia and warrants further investigation 1
- This threshold is based on the 5th percentile of hemoglobin values from the NHANES III dataset of the US population 1
- No downward adjustment should be made for age in males, even though mean hemoglobin decreases in men over 60 years, because lower levels often indicate concurrent pathological conditions 1
Important Clinical Context
When This Definition May Not Apply
The standard hemoglobin threshold of <13.5 g/dL may not be appropriate in males with: 1
- Living at high altitude
- Active smoking
- Age ≥70 years
- Non-Caucasian race
- Chronic lung disease
- Hemoglobinopathy
Comparison to WHO Criteria
- The WHO defines anemia as hemoglobin <13.0 g/dL in adult males 1
- The more conservative threshold of <13.5 g/dL is recommended because it identifies patients earlier who are most likely to have pathological processes contributing to low hemoglobin and who will benefit from evaluation 1
Screening Recommendations
- All patients with chronic kidney disease should have hemoglobin measured at least annually, regardless of CKD stage or cause 1
- More frequent monitoring is indicated for patients with diabetes, greater disease burden, unstable clinical course, or evidence of previous hemoglobin decline 1
- Anemia develops early in CKD and is nearly universal in stage 5 CKD 1
Clinical Significance
- Anemia in adult males typically indicates an underlying pathological process requiring investigation 1
- Iron deficiency is the most common cause of anemia worldwide, accounting for approximately half of all anemia cases 2
- In adult males, iron deficiency anemia should prompt gastrointestinal evaluation for occult blood loss, as menstrual loss is not a factor 2, 3