Confusing blood tests - IgA deficiency? / low ferritin /coeliac?

[Floralbiscuit]

Hi,
I've been going round in circles for my son for several years with unexplained symptoms since birth - many resolved now. He's 8.

He was ill pretty much all of 2023. We were initially told he had strep A (which is when issues worsened) but swabs all came back negative and he didn't seem to recover well for long. We were told by several doctors it was just back-to-back viruses. He had tummy aches and lots of mouth ulcers every day.

He had some blood tests. All were normal apart from a few surprising ones:

• Ferritin came back at 15 which was very low end of reference range.
• Vitamin A was low. Not sure if that result was accurate since he had been unwell. We've supplemented since.
• B12, Active B12, and folate were normal/high
• All other nutritional checks were fine, stool sample for calprotectin and blood were normal.

• We saw a dietitian - she approved his diet. His diet has always been great.
• We saw gastroentology who said results suggest he does not have a stomach issue, and he was discharged.
• We saw haematology who advised we give oral iron until ferritin was at least 50.

My son's ferritin appeared to improve on oral iron - it went from 15 to 86. But six months after stopping, it dropped back to 20. He's back on oral iron again.

After almost 12 months of constant symptoms, my son's tummy aches resolved last spring, and his mouth ulcers improved significantly (only occasional small one now).

One of the things I asked to be checked last year was coeliac disease. In the past he tested positive for the genes involved in CD. Yesterday I looked back through his test result from 2023 and saw the lab had written 'TtG IgG normal' and no result for TgG IgA. I asked his paediatrician who said that usually IgG is tested only when someone is IgA deficient. In other words, it looks like my son's coeliac screen found he is IgA deficient.

As I understand it, lots of people are IgA deficient..... but the odd thing is that my son's IgA had been tested in the past a few times and was normal/slightly elevated. So I don't know why my son would have suddenly become IgA deficient. I don't know if it can be temporary or whether it means he is now permanently IgA deficient, and whether that is related to any/all of his symptoms including issues with iron.

I wonder if anyone experienced temporary IgA deficiency, or IgA deficiency that appeared when it was previously normal? I'm not sure where to go from here or even if it is useful to pursue given my son seems well, other than we can't explain his continued low ferritin. We've been passed back and forth to specialists his entire life about one thing or another, and it just leads to increasing anxiety and no progress.

Sorry for the long post. I needed to get it out of my head since I'm feeling very lost and confused!

Just like any other blood test, there is a certain amount of natural fluctuation in the number for IgA - a one-off low result is not necessarily meaningful, depending on what else is going on in terms of the symptoms. Because you have to test total IgA as part of the celiac testing but it's not the focus of the test, it's often overlooked / ignored if it comes back slightly low.

Persistent low IgA is relatively common but in many people is symptomatic. Because it's usually cause by autoimmune reactions you can go from normal to low levels. What it means for the specific person is variable, and potentially not very much.

https://www.cuh.nhs.uk/patient-information/low-iga-levels-in-children-information-for-parents-and-families/

This is a good page, there is also a longer one from Manchester if you Google it.

If you think your child has persistent symptoms causing concern it's reasonable to mention the result at your next consultation and the person who sees you can either put it up in the context of the medical history themselves or get advice elsewhere. There may be a need to repeat the test or combine with others. This depends on the specific medical history and beyond the scope for discussion on Mumsnet.

• should read Asymptomatic / not symptomatic in para 2 above. Can't find an edit or delete button, possible I am just thick.

IgA deficiency is common and not really significant usually. But if Coeliac is suspected (and it is quite likely in your son's case), an EMA test, with endoscopy/biopsy should be offered because tTG IgA positive is the "gold standard" for coeliac diagnosis, so if there is IgA deficiency that test will give a false negative for Coeliac, so follow up testing should be carried out. A normal tTG IgG isn't enough to rule out Coeliac

Thank you both for your responses. I appreciate the info.