A 10 year old girl presents with fever, vomiting, and mild generalized abdominal pain for 3 days. No other symptoms were present. Her medical, surgical, family, and birth histories are unremarkable, while her growth and development have been normal so far. She is on a standard adult diet. A complete blood count is significant for a Hb of 3.1 g/dL, MCV of 131 fL, and reticulocyte count of 10%. A liver profile reveals a serum bilirubin level of 5.1 mg/dL, with direct bilirubin amounting to 1.2 mg/dL.
The peripheral blood film reveals the presence of macrocytosis, polychromasia, anisocytosis, and microspherocytosis.
Lactate Dehydrogenase (LDH): 521 IU/L (105-333) Urine Urobilinogen: 14 mg/dL (0-8)
- Strongly Positive for IgG - Negative for C3d
- Positive at 37 °C - Negative at 4 °C