Wednesday, March 6, 2013
Interpreting test results for Celiac
There are four basic tests that are used to diagnose Celiac these tests are IgA, IgG, tTG, and ELISA. Of these tests the most commonly used are the IgA and the IgG tests. Many people will get test results without knowing what those test results mean. I have seen instances where the test results are mailed to the person with Normal, Abnormal, Low or High next to a number and a range. Well that is completely useless for most of us since we have no baisis of what this means.
IgA, also known as Immunoglobulin A: With the test IgA your results are positive for celiac if the numbers come up too high or if they come back to low. I know strange right? You would think that if the numbers came back too low you have not have to worry about Celiac, nope truth is now you have to deal with IgA deficiency as well as Celiac. When you look up IgA deficiency you will find a link to Celiac. The range should run 81-463 in an adult this is normal. Anything below or above these numbers can spell out trouble. For reference in young adults or children the numbers runs as such 1-3 y 24-121, 4-6 y 33-235, 7-9 y 41-368, 10-11 y 64-246, 12-13 y 70-432, 14-15 y 57-300. This should give you a reference point only, these are standard numbers but other testing facilities may run on a different scale. With IgA I tested at 48 my first pull and 51 my second confirming test, as you can see just a little over half of the lowest number in the range.
IgG, also known as Immunoglobulin G: with this test you are looking for high numbers if you have low numbers meaning a IgG deficiency then you don't need to worry about celiac. You do need to worry about the deficiency and get it fixed if it is bad enough. Ok so we are looking for high numbers in this test. The normal range in an adult is 717–1,411 on many scales (yours may differ) if your numbers are higher than that you might have an issue.
tTG or Tissue Transglutaminase: as far as I can tell this is a panel of IgA and IgG tests done, this is a serum test meaning more than basic numbers they are looking for a range in this case. The ranges are as follows
<4.0 U/mL (negative)
4.0-10.0 U/mL (weak positive)
>10.0 U/mL (positive)
ELISA test the Elisa test is a wet test it has many uses in this case they are testing for a reaction to gluten proteins that will be indicated by a color change. The test results will say positive or negative reaction in most cases. Positive means you did react to the gluten and negative means you did not react to the gluten. This is not a commonly done test due to the costs. However it is an easy test to read.
Other tests not mentioned are genetic testing and biopsies. They normally will not do these without a precursor test (one of the above) having a positive reaction.
I hope that this post will help those who are struggling to read through test results and are looking to find answers. Please note that the ranges I used may not match the ranges the lab uses.