Match each patient's clinical presentation with the most appropriate confirmatory diagnostic test.
- A 35-year-old woman with a history of systemic lupus erythematosus presents with worsening fatigue and scleral icterus. Labs show a hemoglobin of 7.8 g/dL, mean corpuscular volume of 105 fL, and an elevated reticulocyte production index. Peripheral smear reveals microspherocytes.Direct antiglobulin (Coombs) test
- A 52-year-old man is evaluated for progressive fatigue and intermittent morning dark urine. He recently developed acute abdominal pain, and imaging confirmed thrombosis of the portal and mesenteric veins. Complete blood count shows pancytopenia.Flow cytometry for CD55 and CD59 expression
- A 22-year-old man is treated with nitrofurantoin for uncomplicated cystitis. Three days later, he develops sudden-onset jaundice, back pain, and hemoglobinuria. Peripheral smear shows eccentrocytes and bite cells.Glucose-6-phosphate dehydrogenase enzyme assay
- A 15-year-old boy presents with right upper quadrant pain. Ultrasound reveals multiple pigment gallstones. Physical examination is notable for splenomegaly. His father had a cholecystectomy at age 25. Labs show an elevated mean corpuscular hemoglobin concentration (MCHC).Eosin-5'-maleimide (EMA) binding test
- A 45-year-old woman presents to the emergency department with altered mental status and fever. Laboratory evaluation reveals a platelet count of 22,000/mm³, hemoglobin of 8.2 g/dL, creatinine of 2.1 mg/dL, and elevated lactate dehydrogenase. Schistocytes are prominent on the peripheral smear.ADAMTS13 activity assay
Answer
The presentations match as follows: SLE with spherocytes matches Direct antiglobulin test; Pancytopenia with portal vein thrombosis matches Flow cytometry for CD55 and CD59; Hemolysis post-nitrofurantoin matches G6PD enzyme assay; Pigment gallstones with high MCHC matches EMA binding test; Altered mental status with schistocytes matches ADAMTS13 activity assay.
Each clinical presentation contains classic pathognomonic findings that map to a highly specific diagnostic test for a particular hematologic disorder. The SLE patient with spherocytes has AIHA (Direct Coombs). The patient with pancytopenia and portal vein thrombosis has PNH (CD55/CD59). The patient with acute hemolysis after nitrofurantoin has G6PD deficiency (G6PD assay). The adolescent with pigment gallstones and high MCHC has hereditary spherocytosis (EMA binding). The patient with schistocytes, thrombocytopenia, and confusion has TTP (ADAMTS13).
Step-by-Step Solution
Key Concept
Clinical presentations and confirmatory diagnostics of hemolytic anemias and thrombotic microangiopathies