Order Intrinsic Factor Blocking Antibody Test from JustLabs for $36 ($54 all-in for a single-test order: $36 + one $18 lab & physician order fee per order). Price includes lab processing at Quest Diagnostics. No insurance required.
Intrinsic factor blocking antibodies stop your body from absorbing vitamin B12, and they are the hallmark of pernicious anemia. A positive result is highly specific; a negative one does not rule the condition out, which is why it is often paired with a parietal cell antibody test.
Vitamin B12 cannot be absorbed on its own. Cells in the stomach lining release a protein called intrinsic factor, which binds B12 so the intestine can take it up. In pernicious anemia, the immune system makes antibodies that block intrinsic factor, and B12 deficiency follows no matter how much B12 is in your diet.
This test looks for those blocking antibodies. Quest notes they are found in roughly half of people with pernicious anemia. That makes the test a poor rule-out, but a strong rule-in: specificity is very high, so a positive result, together with low B12 and the right blood count picture, strongly supports the diagnosis.
Pernicious anemia is usually the end stage of autoimmune gastritis, a slow immune attack on the acid-producing part of the stomach. It is more common in people with other autoimmune conditions, especially autoimmune thyroid disease, and Quest notes that some people with thyroid autoimmunity test positive before they ever become B12 deficient.
Knowing the cause matters. Deficiency from diet often responds to ordinary supplements, while pernicious anemia means absorption itself is impaired, so B12 replacement is usually long term and is planned with a clinician. One timing rule applies: Quest asks that the sample not be collected within a week of a vitamin B12 injection, because high B12 levels in the blood can cause a false positive.
Price
$36
All-in
$54
incl. $18 lab & physician fee
Results
2-3 business days
Fasting
Not Required
What's Measured
What This Test Measures
This test detects intrinsic factor blocking antibodies in serum, using an immunoassay at Quest. These autoantibodies attach to the site on intrinsic factor that normally binds vitamin B12, preventing B12 from being absorbed. The result is reported as negative or positive.
Who Should Consider This Test
People with low or borderline vitamin B12, a raised methylmalonic acid, or anemia with large red blood cells who want to know whether the cause is autoimmune; people with symptoms of B12 deficiency such as fatigue, numbness or tingling, balance problems or a sore tongue; and people with autoimmune thyroid disease, type 1 diabetes or a family history of pernicious anemia who are being evaluated for it.
Health Insights
Conditions Screened
Related Symptoms
When to Get Tested
When a low B12, a high methylmalonic acid or an unexplained macrocytic anemia needs a cause, or when a clinician is evaluating you for autoimmune gastritis or pernicious anemia. If you receive vitamin B12 injections, schedule the draw at least one week after your most recent injection.
No fasting needed. How to prepare for your blood test →
Understanding Your Results
Negative means no intrinsic factor blocking antibodies were detected. Because only about half of people with pernicious anemia have these antibodies, a negative result does not rule the condition out; your clinician may look at parietal cell antibodies, gastrin, B12 and methylmalonic acid to complete the picture. Positive means blocking antibodies are present. Specificity is very high, so combined with low B12 and an anemia with large red cells it strongly supports pernicious anemia. A positive result in someone without deficiency yet can indicate a higher risk later. A positive result taken within a week or two of a B12 injection may be falsely positive. JustLabs results are informational; review them with a clinician, who will decide on confirmation and treatment.
What to Expect
After placing your order, we send it straight to Quest Diagnostics — there is no consent form to sign and no partner email to wait for. Your requisition is usually ready to download from your dashboard within about an hour, and you can book your blood draw at any Quest Diagnostics location.
The blood draw typically takes just a few minutes. Results are usually available within 2-3 business days and will appear in your secure JustLabs dashboard.
Our results include reference ranges and easy-to-understand indicators showing whether your values are within normal limits.
How much does the Intrinsic Factor Ab test cost?
The Intrinsic Factor Ab test costs $36 at JustLabs — $54 all-in, since the $18 lab & physician order fee is charged once per order, however many tests you add. The price is fixed before your blood draw; no insurance or doctor visit needed.
| Option | Price | Order all-in | Notes |
|---|---|---|---|
| Intrinsic Factor Ab at JustLabsDrawn at Quest Diagnostics | $36 | $54 | Includes the one $18 fee, charged once per order |
Paying with an HSA or FSA? See which lab tests qualify
Frequently Asked Questions
Hospital cash price: $150–$300
$36
+ $18 order fee · $54 all-inOne $18 fee per order covers your Quest blood draw and the independent physician order, however many tests you add.
- Results in 2-3 business days
- No fasting required
- Physician order included
No insurance needed · HSA/FSA eligible
- Physician-ordered
- CLIA-certified Quest lab
- Drawn at Quest Diagnostics
Need Help Choosing?
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