The most widely accepted testing protocol for celiac disease (basically, the inability to digest gluten) includes a blood test followed by an intestinal biopsy, though there isn’t an exact science behind the diagnosis.
You may be given the following tests in search of a diagnosis:
Blood tests
Biopsies
Urine tests
Stool tests
Genetic tests
The real diagnosis comes after the tests: with the results. Your test results are sometimes easy to interpret, and other times are impossible. For one thing, there are false negatives and occasionally false positives. False negatives can be due to several factors:
Not eating enough gluten prior to testing can affect the amount of antibodies you produce.
Testing that doesn’t include all five blood tests may leave an antibody unnoticed.
About 5 to 10 percent of people don’t produce the antibodies that indicate celiac.
Young children don’t always produce enough antibodies to show a response.
A compromised immune system may weaken the antibody response.
In the very initial stages of sensitivity or disease, you may not have produced enough antibodies or show other signs of the disease — yet.
Some people test negative on some or all the tests, yet they find that they don’t feel right when they eat gluten. Perhaps you got false negatives — or maybe gluten just doesn’t sit right with you. Bottom line: If it makes you feel bad, don’t eat it!