July 19, 2010
Question from Miramar, Florida, USA:
My 10-year-old daughter has had type 1 since the age of six. This year, her yearly blood test came back with elevated celiac levels. She had no symptoms, no stomach issues, rashes, diarrhea, nothing. Her endocrinologist referred her to a gastrointestinal doctor. An endoscopy was performed today and there was no visible celiac detected. The doctor did detect H Pylori and believes she may be positive for that. A biopsy was taken and the results will come next week. Can her biopsy come back negative for celiac even with positive blood work? What would cause her blood work to show celiac levels high if it’s not celiac? Could it had been the H Pylori? What if her biopsy is negative?
ALL blood tests have some degree of error; NO blood test is completely without the possibility of error. If you get a blood sugar result from your glucose meter, the “error” range is about 10 to 20%. So, if the reading were 100 mg/dl [5.6 mmol/L], then the actual glucose reading could be anywhere from 80 to 120 mg/dl [4.5 to 6.7 mmol/L]. But those values are very terrific, so why would one care? In the hospital laboratory, the error rate (for a glucose test), should be only about 5%. So, a serum glucose value of 100 mg/dl [5.6 mmol/L] could actually be anywhere from 95 to 105 mg/dl [5.3 to 5.8 mmol/L]. If the glucose level were 400 mg/dl [22.2 mmol/L] on the reading, it means that the actual glucose reading could range from 380 to 420 mg/dl [21.1 to 23.3 mmol/L]. So, either way, the glucose reading is way too high. (This is part of the reason that a DIAGNOSIS of diabetes mellitus should only be established by a serum glucose level from a vein and NOT from a meter.) the higher the value, in this case, the more likely it reflects “truth”.
That said, I don’t know the error rate for the celiac panel that was done in the blood test. Commonly, the test that you are referring to is a measurement of antibody proteins to a certain enzyme/protein from the intestine called “tissue transglutaminase” (or “ttg”). If the concentration of these antibodies to ttg were in high concentration, then the antibodies could likely actually be present. BUT, just having the antibodies does NOT mean that celiac disease is actively present. Just because you smoke cigarettes does not mean that you WILL get lung cancer, but you are at high risk. So, for celiac disease, the PROOF will be to biopsy the intestine by the scope and look for microscopic changes that are consistent with celiac disease. There are some error rates in this, too: if there are subtle, minimal changes, the biopsy may miss them. But if there are a lot of changes, the biopsy will likely be positive.
So, yes, you can have an irregular blood test for celiac and not (yet) have active celiac disease. What would your doctors do? Probably follow the blood levels of the ttg (or similar) antibodies and see what the levels do. It might mean periodic repeat endoscopic biopsies.
I think a more common scenario is when the blood test for celiac is negative (falsely) and there is actually celiac disease going on. Celiac disease occurs about 8% or so in patients with type 1 diabetes. There may be symptoms related to the intestinal system – there may not be. There may be unexplained enhanced sensitivity to the effects of insulin. There may only be poorer growth in height. There may be NO symptoms at all. THIS IS WHY THE SCREENING IS DONE.
The test for H. pylori (which is a germ that is associated with peptic ulcer disease) is a separate test and is not related to celiac disease or the testing thereof.