False negative serologic tests:
(1) IgA deficiency
(2) severe immunodeficiency
(3) marked immunosuppression
(4) low exposure to gluten prior to testing
(5) poor test performance by the laboratory
False negative small bowel biopsy:
(1) patchy involvement missed on random biopsies
(2) inadequate sampling
(3) low exposure to gluten prior to testing
(4) poor orientation of the villi in the biopsy specimen
(5) inexperienced endoscopist
Diagnostic errors:
(1) failure to order appropriate tests
(2) ascribing findings to another diagnosis
Recommendations:
(1) Take multiple biopsies from multiple sites.
(2) Consider gluten challenge prior to testing.
(3) Testing should be done at a reliable laboratory.
(4) Screen the patient for depressed immunoglobulin levels.
