Tpo antibodies ranges

There has been a change in the reference range for tpo antibodies. I don't know which one to use. My tpo antibodies came back at 13 ium/ml range <35. But I see almost everywhere else mayo clinic etc range is <9 ium/ml. I am symptomatic and family history of thyroid disease...just wondering now which range to go by. It's confusing to me. Any opinion knowledge etc is most welcome. Thanks

[SeasideSusie Remembering]

You go by the range your lab uses. You can't mix and match with a range from another lab.

So if your result was 13 <35 then you are negative.

[Hidden in reply to SeasideSusie]

Thank you