Case 29

1. Presented by Eric A. Gehrie, MD and prepared by Lorraine N. Blagg, MA, MLS(ASCP)SBB

Clinical Vignette

A school aged child presented to the emergency department with dark urine and recent history of pneumonia which had been treated with acetaminophen, cefdinir, and ceftriaxone. The patient's urinalysis showed a 2+ with protein and a large amount of blood with six RBCs per high power field. The urine culture showed no growth. The hemoglobin was 10.3 g/dL, with a hematocrit 28.1%, a total bilirubin of 2.5 mg/dL, and a haptoglobin of <6 mg/dL. The patient's sample was initially too hemolyzed to analyze for lactate dehydrogenase (LDH) or creatine kinase (CK) but was repeated on a new sample with a LDH result of 1457 U/L and a CK of 2550 U/L. A direct antiglobulin test (DAT), serologic drug study and Donath-Landsteiner tests were ordered.

Direct Antiglobulin Test (DAT) Battery:

Serologic Drug study:

Donath-Landsteiner Test:


What is the most likely explanation of the patient's results?