| Cause of anemia | Associated signs and symptoms (in addition to those caused by anemia) | Common laboratory findings |
| Causes associated with active SLE (other findings of active SLE are often present, such as fatigue, arthralgias or arthritis, mucocutaneous disease, nephritis, and/or hepatitis) |
| Anemia of chronic disease/anemia of inflammation (ACD/AI) | | - MCV normal or (less commonly) low
- Low reticulocyte count
- Blood smear unremarkable
- Adequate iron stores
- Elevations in ESR, CRP, and ferritin
|
| Autoimmune hemolytic anemia (AIHA) | - May be relatively asymptomatic or critically ill
- May have jaundice and/or dark urine if hemolysis is intravascular
- May have acrocyanosis in cold agglutinin disease (rare)
| - MCV high, low, or normal, RDW increased
- High reticulocyte count
- Blood smear may show spherocytes and/or RBC agglutination
- Increased indirect bilirubin and LDH
- Low haptoglobin
- Positive direct antiglobulin (Coombs) test
|
| Acquired aplastic anemia (autoimmune destruction of hematopoietic cells in the bone marrow) | - May have symptoms or complications related to other cytopenias (eg, infection with neutropenia, bleeding with thrombocytopenia)
| - MCV normal
- Very low reticulocyte count
- Blood smear with decreased WBCs and platelets, but RBCs are unremarkable
- Low WBC and platelet counts
|
| Thrombotic thrombocytopenic purpura (TTP) | - May have impaired kidney function, neurologic symptoms, gastrointestinal symptoms, and/or cardiac symptoms
| - MCV may be low if schistocytes are abundant; RDW increased
- High reticulocyte count
- Blood smear with schistocytes and reduced platelets
- Severe thrombocytopenia
- Increased indirect bilirubin and LDH
- Low haptoglobin
- Severely reduced ADAMTS13 activity (generally <10%)
|
| Catastrophic antiphospholipid syndrome (CAPS) | - Multiorgan involvement and/or failure due to diffuse coagulopathy
- Venous and/or arterial thromboembolism, often multiple and multifocal
| - MCV may be low if schistocytes are abundant; RDW increased
- High reticulocyte count
- Blood smear with schistocytes and reduced platelets
- May have concomitant disseminated intravascular coagulation
- 1 or more positive antiphospholipid antibodies (lupus anticoagulant, anticardiolipin, anti-beta2GPI)
|
| Medications used to treat SLE |
| Gastrointestinal blood loss with iron deficiency from NSAIDs and/or glucocorticoids | - May be associated with abdominal pain, nausea, hematemesis, and/or bloody stool
| - MCV low if iron deficiency, high if reticulocytosis
- High reticulocyte count unless iron deficiency develops
- Blood smear unremarkable
|
| Hemolysis from hydroxychloroquine (in people with G6PD deficiency) or dapsone | - May have jaundice and/or dark urine if hemolysis is severe
| - MCV low if microspherocytes, high if reticulocytosis
- High reticulocyte count
- Blood smear may show spherocytes, bite cells, or blister cells
- Increased indirect bilirubin and LDH
- Low haptoglobin
|
| Bone marrow suppression from hydroxychloroquine, methotrexate, azathioprine, mycophenolate, calcineurin inhibitors, and/or cyclophosphamide | - May have symptoms or complications related to other cytopenias (eg, infection with neutropenia, bleeding with thrombocytopenia)
| - MCV normal
- Low reticulocyte count
- Blood smear with decreased WBCs and platelets, but RBCs are unremarkable
- Low WBC and platelet counts
|
| Causes unrelated to SLE disease activity |
| Iron deficiency | - May have pica, restless legs syndrome, hair loss, headache, depression, irritability
| - MCV normal or low
- Low reticulocyte count
- Blood smear with microcytosis, target cells, hypochromia (if severe)
- Low serum ferritin (<30 ng/mL or <100 ng/mL with concurrent inflammation) and/or low transferrin saturation (TSAT; <20%)
|
| Vitamin B12 deficiency, including pernicious anemia, or folate deficiency | - May have glossitis, neuropsychiatric symptoms (eg, neuropathy, cognitive slowing, gait abnormalities), and/or changes in skin pigmentation
| - MCV high
- Reticulocyte count low
- Blood smear with megaloblastic changes (macrocytosis, hypersegmented neutrophils)
|
