In Vivo Non Imaging Procedures:

SINGLE SCHILLING TEST

INDICATIONS

• Rule out pernicious anemia
   
• Identify malabsorption syndrome unrelated to IF deficiency
   

RADIOPHARMACEUTICAL

• *Co-B₁₂ for first stage of test
   
• *Co-B₁₂ + Intrinsic Factor Capsule for second stage
   

PROCEDURE

STAGE 1

• *Co-B₁₂ capsule given orally, followed by IM injection of 1 mg non-radioactive Vitamin B₁₂. This non-radioactive Vitamine B₁₂ is given to block B₁₂ binding sites in the liver.  If not administered, essentially all the radioactive B₁₂ localizes in the liver and little or none is excreted in the urine, invalidating the test.

• Competent 24 hr urine collection

• Determination of % excretion in urine.
   
• If normal value obtained (>10%), test completed; no further action required.

 

 

STAGE 2

• If excretion from Part 1 Schilling Test is < 6%, then 3-5 days later another capsule of *Co-B₁₂ is administered orally along with a capsule containing 1 NF unit of Intrinsic Factor
   

• This capsule is then followed by IM injection of 1 mg non-radioactive Vitamin B₁₂.

• Another competent 24 hr urine collection is then performed by patient and % excretion in urine is determined.
   

INTERPRETATION

 % Excretion

Part 1	Part 2	Interpretation
>10	-----	normal
<6	<6	Malabsorption Syndrome unrelated to intrinsic factor
<6	6-12	Pernicious Anemia

 

LIMITATIONS

• False positives from incomplete urine collection
   
• False negatives if other radioisotopes "on board"
   
• False negatives if patient is on Vitamin B₁₂ therapy