Help with understanding test results.

[Numbsew]

Please could I have help with understanding test results? I have had a parietal cell autoantibodies test and a faecal calprotectin content test. Both of these have come back as normal. Does this mean that I don’t have PA?

[Gambit62 Administrator]

faecal calprotectin is a test relating to conditions like crohns - I don't think it is a test related to PA

nice.org.uk/guidance/dg11

GPCA test is not recommended as a test for PA in the UK or by the WHO because it is prone to give false positives. Not sure what the incidence of false negatives. However, it's only one part of the PA equation. The test recommended in the UK is IFA but that's rather prone to giving false positives (40-60%) of the time. Although a positive is much better at confirming that PA is present a negative is a long way from ruling it out.

[Numbsew in reply to Gambit62]

Thank you for explaining. I have read so much about different stuff that I have got confused. The b12 injections I have had have initially increased neurological symptoms. I am now beginning to Improve. Am I right in thinking that if I was not deficient, Injections would not have had any neurological effect either positive or negative? In the absence of clear test results and with a serum b12 of 319 I am kind of banking on an increase in dizziness, tingling and numbness following injections to indicate that I must have been deficient, otherwise there would have been no impact?

[Gambit62 Administrator in reply to Numbsew]

unfortunately people respond very differently to injections. Many notice symptoms seeming to get worse for a while after injections. Some notice nothing for months.

The fact that you are improving implies that B12 was probably involved.

In some ways it is easier to rule out other possible causes of a B12 absorption problem - so testing for things like crohn's is a good move.

[fbirder]

More people without PA have antibodies to Gastric Parietal Cells than with PA. So a positive result doesn't mean that you do have PA.

However, the vast majority of those with PA do have the antibodies. So a negative result does suggest that you don't have PA.