Monday, June 29, 2009


You're doing lab medicine and get the two blood smears shown above. Your attending tells the team to order a historically important test. The team gives the patient 2mcg oral radio-labeled drug A and 1000 mcg intramuscular non-labeled A. Urine is collected and the excretion of radio-labeled A is low (<8% of the administered dose).

The team then repeats this test but also gives oral drug B along with the oral drug A, followed by the intramuscular non-labeled A. The urine collection now shows normal excretion of the radio-labeled molecule A (8-35%).

Challenge: What is the diagnosis and how is the coin shown above related?

First image is in the public domain (photoshopped by me), second and third images shown under Fair Use.


tree said...

Vitamin B12 deficiency, Schilling test (schilling coin)

Anonymous said...

schilling test to test for causes of B12 deficiency (leading to megaloblastic anemia)

a s(c)hilling for your thoughts on whether this is correct.

Alex said...

b12 def?

Craig Chen said...

haha yes! Nice job! One of those outdated tests they teach to first and second years.

The coin shown is an Austrian schilling; the test described in the Schilling test. The second image shows macroovalocytes; the third image shows a hypersegmented neutrophil. This is pernicious anemia (antibodies to intrinsic factor) causing vitamin B12 (cobalamin) deficiency. Here, molecule A is cobalamin. The first test suggests pernicious anemia or intestinal malabsorption; the second test with the addition of intrinsic factor (molecule B) confirms pernicious anemia.

Sources: UpToDate; Wikipedia, second and third images originally by Dr. Stanley Schrier.