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It depends WHICH screen has been used. There are about 4 different tests
on the market, in addition some of the hospitals run their own in-house
ones. Thus this information is important before any interpretation can be
made. Our research experience was that it was far better to 1. use a test
that had a total gliadin antigen preparation in it (i.e. what this means
is that some company products have a subfraction of the wheat protein in
the test, which while it detects most celiacs, can miss some if they have
antibodies to slightly different proteins in wheat gluten), and
2, use a test for both IgG and IgA type antibodies - again, use of IgA
alone misses some celiacs that have an IgA deficiency.
 
John Skerritt