Web: | mayocliniclabs.com |
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Email: | mcl@mayo.edu |
Telephone: | 800-533-1710 |
International: | +1 855-379-3115 |
Values are valid only on day of printing. |
If the vitamin B12 concentration is less than 150 ng/L, then the intrinsic factor blocking antibody (IFBA) test is performed. If IFBA result is negative or indeterminate, then the gastrin test is performed.
If the vitamin B12 concentration is 150 to 400 ng/L, then the methylmalonic acid (MMA) test is performed. If the MMA result is greater than 0.40 nmol/mL, then the IFBA test is performed.
See Vitamin B12 Deficiency Evaluation in Special Instructions.
Patient Preparation:
1. This test should not be ordered on patients who have received a vitamin B12 injection within the last 2 weeks.
2. Patient should be fasting for 8 hours.
3. If medically feasible, proton pump inhibitor (omeprazole, lansoprazole, dexlansoprazole, esomeprazole, pantoprazole, and rabeprazole) therapy should be discontinued 1 week before measurement of serum gastrin levels.
4. Drugs that interfere with gastrointestinal motility (eg, opioids) should be discontinued for at least 2 weeks before serum gastrin testing.
Container/Tube:
Preferred: Red top
Acceptable: Serum gel
Specimen Volume: 4 mL
Collection Instructions:
1. Divide specimen into 3 plastic vials, 1 containing 1 mL (label as PAGAS), 1 containing 1.5 mL (label as PAMMA), and 1 containing 1.5 mL (label as B12PA).
2. Band specimens together.
If not ordering electronically, complete, print, and send a Benign Hematology Test Request Form (T755) with the specimen.
Gross hemolysis | Reject |
Gross lipemia | OK |
Gross icterus | Reject |
Specimen Type | Temperature | Time | Special Container |
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Serum | Frozen (preferred) | 30 days | |
Refrigerated | 24 hours |