I don't understand my blood test results

[Gary W. Hamilton]

Here are my blood test results. What is the verdict? Is this a standard test series?

Endomysial IgA Ab value:  Negative

Transglutaminase (tTG) IgA value: 19U/mL

Immunoglobulin A, Qn, Serum value: 268 mg/dL 

[trents]

Welcome to the forum, Gary!

In order to address your question we would need the reference range for the tTG-IGA value. There is no standard. Each lab uses their own scale. So, please give us the negative vs. positive range for that one. Same for the Immunoglobulin A, Qn.

Edited February 2, 2023 by trents

[Gary W. Hamilton]

Thanks for the quick response.

tTG-IgA value 19 U/mL

Standard Range: 0-3 U/mL

Negative 0-3

Weak Positive 4-10

Positive >10

Immunoglobulin A, Qn, Serum value 268mg/dL

Standard Range: 61-437 mg/dL

[trents]

Since your total IGA (Immunoglobulin A, Qn) is not low, the tTG-IGA (which is a fraction of total IGA) test value returned should be reliable. Low total IGA drives the individual IGA values down. So, this is not a problem in your case.

Your tTG-IGA is unequivocally positive. This is a strong indication of having active celiac disease. There are other antibody tests that could have been run but the tTG-IGA is kind of the go to minimum for most medical practitioners.

[Gary W. Hamilton]

Thanks for correlating the total IGA and tTG-IGA. Your simple explanation of reliability of the tTG-IGA is very helpful. Since the Endomysial IgA Ab was negative I was questioning the diagnosis.

The reason for my questioning the diagnosis is that I am 65 years old and only started having significant stomach and digestive issues for the past year or so. Prior to that I just thought I had a "nervous stomach".    

[Scott Adams]

Has your doctor referred you for an endoscopy to confirm celiac disease? This is the usual next step in the diagnostic procedure. If so, you will need to keep eating gluten daily until that procedure is completed. If you don't want that procedure you could try a gluten-free diet to see if your symptoms go away, as your blood test result is pretty definitive. Just in case, this article may be helpful:

 

[trents]

58 minutes ago, Gary W. Hamilton said:

Thanks for correlating the total IGA and tTG-IGA. Your simple explanation of reliability of the tTG-IGA is very helpful. Since the Endomysial IgA Ab was negative I was questioning the diagnosis.

The reason for my questioning the diagnosis is that I am 65 years old and only started having significant stomach and digestive issues for the past year or so. Prior to that I just thought I had a "nervous stomach".    

Different celic antibody tests vary in their "sensitivity" and their "specificity". The Endomysial IGA is very specific for celiac disease which means a positive for that one all but eliminates other disease possibilities. It is also an expensive test. However, it is not very sensitive which means a negative misses many who actually do have celiac disease. The tTG-IGA combines good sensitivity with good specificity and is inexpensive. So, the tTG-IGA has become the defacto go to test for the average physician. In an ideal world, every physician should order a "full panel" antibody test but general lack of knowledge about what can be done, combined with cost containment, does not make for an ideal diagnostic process. Interestingly, the tTG-IGA test misses about 20% of those from a white European background and about 80% of those with a black African background. Here is a primer for what tests are available if you are interested: https://celiac.org/about-celiac-disease/screening-and-diagnosis/screening/

The gold standard test for celiac disease is an endoscopy with biopsy of the small bowel lining. Your physician may want you to get this done for confirmation. It is important for you to be consuming regular amounts of gluten until that has been done so that healing of the small bowel villous lining doesn't happen which would confuse things by producing a negative result.

Celiac disease can onset at any stage of life. If you are diagnosed with celiac disease you have likely had it for more years than you realize. It takes around 10 years for the average person to get a diagnosis because the symptoms mimic so many other diseases and because of the general ignorance of gluten disorders in the medical community. Acute symptoms often don't start to appear until damage to the small bowel villi become pronounced and so we have a lot of "silent" celiacs running around with no or with minor symptoms that they attribute to something else.

[Gary W. Hamilton]

Thanks trents and Scott. This forum has already paid off for me. I did get an endoscopy including 6 biopsies. It confirmed the diagnosis of Celiac disease. Obviously this is a life changing diagnosis so I  have been very skeptical. The same doctor who ordered the blood test performed the endoscopy (an independent pathology lab provided the biopsy results) so I was a little concerned he might have had a bias to confirm a diagnosis he had already made.     

Life is a journey, time for a course change. 

[trents]

Now the fun begins. Learning to eat truly gluten free (instead of just "lower gluten") is much more of a challenge than most people realize at the outset. Gluten is found in places you would never expect, like Campbell's Tomato Soup (most canned soup's, really) and soy sauce. And then there is the whole problem of cross contamination, especially when eating out. I urge you to read the article Scott linked above, "Start Here".

The biggest challenges are the social ones: