Hi all those who can understand results and what they mean.
My Intrinsic factor antibody blood test result was 0.99 U/ml which was described as Normal - No Action The reference given was <1.20U/ml also a note saying method and reference change as of 05/03/15
At the time of the test I had been taking sublingual B12 which had raised my B12 up from 178 to 452 ng/L ref range 150-900ng/L
I can believe I do not have PA but cannot understand why my B12 had dropped to 178 which was tested a month after taking B12 for a month, so it may have been much lower?
Most of my classic B12 deficiency symptoms started a couple of years after having a very traumatic appendectomy when I wonder if a good part of my ileum may have been cut out as my gastric problems started then. As a side question is there any way of finding out for sure?
Thanks for any input.
Written by
jointpain
To view profiles and participate in discussions please or .
IFA is a good test for showing that you do have PA - it tends not to give false positives (unless done to close to supplementation).
However, it is a really bad test for showing that you don't have PA as it gives false negatives 40-60% of the time depending on the exact test method - so a negative is a long way from showing that you don't have PA.
if nitrous oxide was used as an anaesthetic during the surgery that may well have inactivated your stores of B12 - the body normally rebuilds them quite quickly but if you have an absorption problem you may not have been able to rebuild them - which would explain the symptoms starting at that point.
Thank you Gambit62 I had the appendectomy in 1996 a long time ago! Since then I have been too regular a visitor to the doctors, in light of the possibility that the IFA test is wrong I wanted to know how close a call is it? Like, am I easily normal on the borderline normal it is the numbers I don't understand. I don't want to go back and say my result at 0.99 is too close to call and be told I am wrong and be labelled as a hypochondriac as I feel I was at the previous surgery I was registered at.
it isn't about where your test is in the range - the test just isn't that useful in ruling out PA - and it is more to do with the test method and the use and existence of other substances in your blood and the test process that can be confused with IFA which is why the limit isn't 0.
If you want to raise this with your GP then I'd suggest referring the to the BCSH guidelines on diagnosis and treatment of cobalamin and folate deficiencies which they can access through the BNF - this includes a discussion of the limitations of all of the tests used in diagnosing B12 deficiency - including IFA
The finding of a low total serum cobalamin level may be further evaluated by testing for anti-IFAB. If positive, the test has a high positive predictive value (95%) for the presence of pernicious anaemia (Toh et al, 1997), with a concurrent low false positive rate (1–2%) i.e. a high specificity. It identifies those patients with a need for lifelong cobalamin replacement therapy. IFAB is positive in 40–60% of cases (Ungar et al, 1967), i.e., low sensitivity, and the finding of a negative IFAB assay does not therefore rule out pernicious anaemia (hereafter referred to as AbNegPA). In addition, the positivity rate increases with age (Davidson et al, 1989) and in certain racial groups [Latino-Americans and African-Americans; (Carmel, 1992)].
Thank you Sleepybunny a very comprehensive answer if ever I saw one!
As to "I am not medically trained" you seem well on the ball, not like any doctors I have seen in the past 22 years! Even though I recently changed surgeries the most recent doctor never knew of sublingual B12 or sprays! Which gives you some idea what I am up against. I will go back to them and maybe tell them what I want rather than play stupid, allowing them to fob me off with whatever is profitable for them. I will work my way through your reading matter as we are well and truly snowed in here in North Wales for the next few days. The drifts are as high as the hedges! So no way of getting out!
Content on HealthUnlocked does not replace the relationship between you and doctors or other healthcare professionals nor the advice you receive from them.
Never delay seeking advice or dialling emergency services because of something that you have read on HealthUnlocked.
GP didn't order intrinsic factor test!
Intrinsic factor antibody test ranges?? 
Intrinsic Factor test result
Intrinsic antibody test after B12 multivits
Intrinsic Factor Antibodies
