- For the genetic component only: gluten consumption prior to testing would not impact the results. Continue with current eating pattern. No change in gluten consumption is necessary.
- For serology markers (antibody titers) Because antibody titers are exposure related, purposeful avoidance of gluten can cause a decrease of serological results. Therefore, the patient’s exposure to gluten containing grains should be considered when interpreting tTg and DGP serology results.
For those without a current diagnosis of celiac disease or wheat allergy, who have been avoiding gluten, a consumption of gluten (≥ 1 ½ slices of wheat bread or equivalent daily) for a minimum of the first two weeks of the last four weeks, prior to testing, is recommended.
Of the 4 celiac disease antibodies that are measured within the CICA, tTg-IgA is the most highly studied and most of our knowledge of the temporal relationship between the presence of antibody and the exposure to gluten come from that antibody. It is likely that the other antibodies have a similar pattern, but we cannot be certain.
For those in this category, who have been avoiding gluten for an extended period of time and who feel adverse reactions when gluten is consumed, a consultation with the health care practitioner regarding the re-introduction of gluten to the eating pattern prior to testing, is recommended. Perhaps another way to approach the issue of gluten avoidance prior to testing is to recommend testing in the individual’s current avoidance state. If the antibody results are positive then the avoidance did not have a significant effect. If the test is negative, then it is unknown whether the avoidance had an effect, so it might be helpful to retest after an interval of gluten exposure.