Practical exclusions to diagnose UAA
| Potential cause of anemia . | Definition . |
|---|---|
| Nutritional deficiencies | Nutrient levels below reference range |
| Iron deficiency∗ | Ferritin <50 ng/mL |
| B12 deficiency | <200, <300 μmol/L with elevated MMA |
| Folate deficiency | < Lower limit of normal |
| Blood loss | Positive history of blood loss or positive fecal occult blood |
| Anemia of inflammation | Presence of known inflammatory condition that commonly causes anemia Iron studies with low iron, elevated ferritin, low/normal TIBC |
| Anemia of CKD† | Estimated GFR <30 mL/min per 1.73 m2 |
| Thyroid disease | TSH <0.1 or >10 ng/mL |
| Medications | Review medication list for medications that cause myelosuppression or drug-induced hemolysis |
| Hemolytic disorders | Review family history, hemolysis labs, and peripheral smear |
| Warm or cold AIHA | Positive direct antiglobulin test |
| Hemoglobinopathies (eg, SCD or thalassemia) | Sickled cells, target cells, and or hemoglobin C crystals on blood film, confirm diagnosis Positive diagnosis by hemoglobin electrophoresis, HPLC, or genetic testing MCV <80 fL, no iron deficiency is consistent with α- or β-thalassemia, confirm if possible |
| Membranopathy (eg, hereditary spherocytosis) | Abnormal red cell morphology on peripheral smear and inherited red cell membrane genetic defect |
| Hematologic malignancy | MDS is diagnosed if MDS diagnostic criteria are met Diagnostic findings on BM or ancillary testing. Suspect if more severe anemia, other cytopenias, or macrocytosis |
| Potential cause of anemia . | Definition . |
|---|---|
| Nutritional deficiencies | Nutrient levels below reference range |
| Iron deficiency∗ | Ferritin <50 ng/mL |
| B12 deficiency | <200, <300 μmol/L with elevated MMA |
| Folate deficiency | < Lower limit of normal |
| Blood loss | Positive history of blood loss or positive fecal occult blood |
| Anemia of inflammation | Presence of known inflammatory condition that commonly causes anemia Iron studies with low iron, elevated ferritin, low/normal TIBC |
| Anemia of CKD† | Estimated GFR <30 mL/min per 1.73 m2 |
| Thyroid disease | TSH <0.1 or >10 ng/mL |
| Medications | Review medication list for medications that cause myelosuppression or drug-induced hemolysis |
| Hemolytic disorders | Review family history, hemolysis labs, and peripheral smear |
| Warm or cold AIHA | Positive direct antiglobulin test |
| Hemoglobinopathies (eg, SCD or thalassemia) | Sickled cells, target cells, and or hemoglobin C crystals on blood film, confirm diagnosis Positive diagnosis by hemoglobin electrophoresis, HPLC, or genetic testing MCV <80 fL, no iron deficiency is consistent with α- or β-thalassemia, confirm if possible |
| Membranopathy (eg, hereditary spherocytosis) | Abnormal red cell morphology on peripheral smear and inherited red cell membrane genetic defect |
| Hematologic malignancy | MDS is diagnosed if MDS diagnostic criteria are met Diagnostic findings on BM or ancillary testing. Suspect if more severe anemia, other cytopenias, or macrocytosis |
AIHA, autoimmune hemolytic anemia; GFR, glomerular filtration rate; HPLC, high-performance liquid chromatography; MMA, methylmalonic acid.
Ferritin levels in older adults and people with conditions such as chronic heart failure may experience absolute iron deficiency at ferritin levels up to 100 μg/L (or up to 300 μg/L if their TSAT is <20%).
CKD is more likely to be the cause of anemia when eGFR is <30 mL/min per 1.73m2; however, is still a possible diagnosis when the eGFR is <60 mL/min per 1.73m2. In older adults, the eGFR cutoff for excluding UAA is 30 mL/min per 1.73m2 if reversible causes are excluded.