Help with blood test results please

[ShonaGreen]

Hi, I’ve recently got access to my full records on Patient Access . In July 2020 I had a lot of blood tests done as I was being being checked for POTS, and I didn’t know about some of them which I think are also used for investigating vasculitis:

Myeloperoxidase MPO - 3.2

Proteinase 3 - 2.3

There were no ranges and no ANCA test was done this time. It could be because I was tested for this in 2018 and it was negative. But looking on Google I think the usual range for MPO is >3.5 for equivocal and >5 for positive. For Proteinase 2-3 is equivocal and > 3 is positive. So I’m equivocal for Proteinase and close to it for MPO, but technically negative. But what does that mean? Would you need both to be firmly positive to be sure it’s vasculitis? I know with thyroid levels that being close to the top or bottom of the range can mean something, but is it the same with this? I’d just like to know your thoughts please whether these results are helpful or not?

I met with the Rheumatologist yesterday and had lots of blood taken and a chest x-ray. She thinks it’s possible I have vasculitis, and is checking for other things too as thinks there’s likely to be a circulation problem as she noticed livedo reticular on my legs too (which I thought was just normal) and my swollen hand is very bad at the moment and I can’t bend 2 fingers or use my hand properly.

Thanks for your help!

[PMRpro]

Does this help?

labtestsonline.org/tests/an...

Were there also no units?

Once the antibody tests are shown to be positive they usually would do further testing to find titres - those numbers would have been considered normal when I worked in a lab.

But they are still helpful. Tests don't have to be strongly positive to add to the image that is being created by using available tests together with symptoms - negatives are just as important when the experts look at the overall results.

[ShonaGreen in reply to PMRpro]

Hi PMRpro thanks for your message and the info. Just looked again and no units either, here’s a photo, but looks like I’m not positive for either with the references I’ve seen now. Will wait to see what the new tests show.

MPO

[xz3sgn in reply to PMRpro]

Dear PMRpro,I'm MPO patient with impaired kidneys but on remission for the last four years(fortunately). However my ANCA remains around 3 titre . It is low but when I had the attack it was 12. Appreciate that Vasculitis can surface even if one doesn't show up ANCA, Is there a lower limit that can be overlooked as long as there is no corroborating evidence of disease, Like CRP below 5 is supposed to be insignificant, Is there such a lower level for ANCA ?

[PMRpro in reply to xz3sgn]

Sorry, really can't help there but low titre results are often found in patients with no vasculitis.

[Chris-Bromsgrove]

Hi Shona. Just for clarification the antibody tests you have had are ANCA tests. PR3 and MPO are the two types of ANCA associated with vasculitis. It does seem that the results are more or less negative, although that doesn't rule out vasculitis entirely. Some people can have vasculitis and be ANCA negative