Autoimmune Hemolytic Anemia: The Daily PANCE Blueprint
A 34-year-old woman with systemic lupus erythematosus presents with 2 weeks of fatigue, exertional dyspnea, and dark urine. She is pale and mildly jaundiced, and the spleen tip is palpable. Hemoglobin is 7.8 g/dL, the reticulocyte count is 9%, LDH is elevated, haptoglobin is undetectable, and the peripheral smear shows many spherocytes. Platelet count and coagulation studies are normal. Which of the following tests is most likely to establish the cause of her anemia?
A. Direct antiglobulin (Coombs) test
B. Osmotic fragility test
C. Hemoglobin electrophoresis
D. Glucose-6-phosphate dehydrogenase (G6PD) assay
E. Serum ferritin
Answer and topic summary
The answer is A. Direct antiglobulin (Coombs) test
The labs prove hemolysis (high reticulocytes, high LDH, absent haptoglobin), and spherocytes narrow the cause to two conditions: hereditary spherocytosis or warm autoimmune hemolytic anemia. The test that separates them is the direct antiglobulin (Coombs) test, which is positive for IgG (with or without C3) in warm AIHA and negative in hereditary spherocytosis. Warm AIHA is associated with lupus, chronic lymphocytic leukemia, lymphoma, and drugs such as methyldopa and penicillins; the spleen removes antibody-coated cells, leaving spherocytes. First-line treatment is glucocorticoids, with rituximab or splenectomy for refractory disease, plus folic acid. Osmotic fragility is abnormal with any spherocytes, so it cannot tell the two apart. Cold agglutinin disease is caused by IgM, so the DAT is positive for C3 only, often after Mycoplasma or EBV.
View blueprint lesson
Smarty PANCE Content Blueprint Review:
Covered under ⇒ PANCE Blueprint Hematology ⇒ ⇒
