Confused about test results

[KikiSa]

Hello,

My child received a ‘weak positive result’ on a routine bloodwork for TTG Iga. The result was measured in U/ml. A repeat test a few months later (while waiting for endoscope) now shows high (but the result is in KIU/L). I’m told the lab ‘just changed the way they report’. I’m wondering if this is an error, or if anyone knows how to convert the units.

[Scott Adams]

It's understandable to be concerned about the unit change between your child's test results. TTG-IgA can be reported in different units (U/mL or kIU/L), and some labs use a conversion where 1 U/mL equals approximately 1 kIU/L. However, since reference ranges and assay methods vary by lab, it's best to confirm with them directly. Ask the lab or your doctor to clarify whether the new result is truly higher or if it’s just a reporting difference. This will help avoid confusion before the endoscopy. Hope you get clear answers soon! Let us know.

[KikiSa]

21 hours ago, Scott Adams said:

It's understandable to be concerned about the unit change between your child's test results. TTG-IgA can be reported in different units (U/mL or kIU/L), and some labs use a conversion where 1 U/mL equals approximately 1 kIU/L. However, since reference ranges and assay methods vary by lab, it's best to confirm with them directly. Ask the lab or your doctor to clarify whether the new result is truly higher or if it’s just a reporting difference. This will help avoid confusion before the endoscopy. Hope you get clear answers soon! Let us know.

Thank you very much for your response Scott. Apparently the second TTG Iga test was ten times the normal. I’m just surprised that there can be such a huge difference between the test results. It concerns me also that the lab has just recently changed their reporting. There are not really many/ any symptoms anymore. I was suspicious about celiac several years ago, and had my child tested then (it was negative then), so we never thought further about it as the pediatrician continued to tell us his shorter stature must be genetic even though we are average height parents. Also I did not have as much knowledge at the time. I guess we will know more after the endoscopy. It pains me to think this may have been an issue for years. I worry now if we are getting false negatives for my other children also.

[Scott Adams]

In the Europe the new protocol for making a celiac disease diagnosis in children is if their tTg-IgA (tissue transglutaminase IgA) levels are 10 times or above the positive level for celiac disease.

According to the latest research, if the blood test results are at certain high levels that range between 5-10 times the reference range for a positive celiac disease diagnosis, it may not be necessary to confirm the results using an endoscopy/biopsy:

• Blood Test Alone Can Diagnose Celiac Disease in Most Children and Adults
• TGA-IgA at or Above Five Times Normal Limit in Kids Indicates Celiac Disease in Nearly All Cases
• No More Biopsies to Diagnose Celiac Disease in Children!

 

[KikiSa]

Yes, I did read about the bloodwork diagnosis option and was given the choice for further bloodwork or proceeding with endoscopy. At this point we would like a definitive answer as it will be a lifelong diagnosis and we realize we would have to go back on gluten if we ever wanted endoscopy in the future. I was reading an article from a GI specialist that was of the same opinion, but yes, difficult decision when it comes to your children.

[Scott Adams]

Honestly, with a 10x or higher level on a TTG-IgA score, there is really no other explanation but celiac disease, at least in my humble opinion.