I'm trying to find some help interpreting my lab results. There's a discrepancy I've found between what the lab at my hospital is using as reference values and what I'm seeing online.
My ANA was positive, but the lab doesn't report titer levels (maybe that is a clue in and of itself about the lab)
My SSA (Ro) came back at 52u/ml. The cutoff value they are using for a positive result is 90u/ml. HOWEVER>
What I'm seeing online is telling me that values over 40 are positive result. Here's the catch: the online table I've found from a major lab here in the U.S. is reporting the units as Au/ml. That is where my confusion comes in.
Are these the same units of measurement? I am thinking they are and the 'A' refers to antibodies.
If you can help at all, it would be greatly appreciated. Also, your experiences with SSA values and what your doc says they mean would be helpful as well.
I recall hearing that "au" means arbitrary units, while "u" just means units. So, I don't think that you can compare "u/ml" to "au/ml" as they're probably NOT the same. Maybe call your doctor's office and ask?
The ANA test you had done is simply a screening, which comes back as positive or negative. If the blood was drawn with a week, the lab should still have your serum and may be able to "add on" a titer for it. It is the way the Dr. ordered it that determines how it is done. A titer is helpful to determine how positive it is. The higher the titer, usually the more meaningful it is. I would call your Dr's office and ask if they would add on a titer if it has been within 7 days. Most labs keep serum that long just for this purpose. Adding on an anti-DS DNA would be helpful, as well as Smith antibody if they have enough to run those too. Customer service at the lab could probably answer your question about the units on the SSA. It is frustrating when labs use different reference ranges so wide that it makes interpretation of results difficult.
Thanks! Unfortunately, the lab my neuro guy used doesn't report the titer level and uses some kind of weird system for reporting levels of the subtests. I've been in touch with my internist and we're going to repeat the tests and send them to an outside lab that can give us more meaningful results.
Like a lot of people who find their way here, I'm frustrated that we can't figure some things out. The best working guess so far has been an atypical multiple slcerosis, but when the ANA came back positive (I do get that it is a screening tool) I was starting to think that we might be closer to an explanation. In fact, some kind of autoimmune disease (not that I want one) would just about explain everything.