Normal SDMA but high creatinine?

[FeebysOwner]

Apparently, Antech labs started doing SDMA testing about three years ago, and now just recently has added to a bloodwork 'package' of tests. This package was done on Feeby just two days ago. She has never had an SDMA test done before but has been deemed to have CKD for probably at least two years now.
What I found odd is that her SDMA level came out as 8.8 (<15 is considered within the 'normal' range), but her creatinine is 3.5 (0.6 - 2.4 normal range). I know that SDMA is usually done multiple times over a long period to watch for trending upward, but it is considered a pretty accurate test regardless. Even the IRIS guidelines on CKD staging have no 'notations' of SDMA test results below 15.

Has anyone else's cat had 'normal' SDMA readings even though other kidney markers clearly indicate CKD? I know in the long run it doesn't matter or change the fact she has CKD, but I am just curious if this has happened with other cats. Thanks.

 

[Twylasmom]

Apparently, Antech labs started doing SDMA testing about three years ago, and now just recently has added to a bloodwork 'package' of tests. This package was done on Feeby just two days ago. She has never had an SDMA test done before but has been deemed to have CKD for probably at least two years now.
What I found odd is that her SDMA level came out as 8.8 (<15 is considered within the 'normal' range), but her creatinine is 3.5 (0.6 - 2.4 normal range). I know that SDMA is usually done multiple times over a long period to watch for trending upward, but it is considered a pretty accurate test regardless. Even the IRIS guidelines on CKD staging have no 'notations' of SDMA test results below 15.

Has anyone else's cat had 'normal' SDMA readings even though other kidney markers clearly indicate CKD? I know in the long run it doesn't matter or change the fact she has CKD, but I am just curious if this has happened with other cats. Thanks.

What I have found with Twyla is that the SDMA was highest when she was first diagnosed with CKD. At her last checkup it was 16, but last spring it was in the 30s! I think the SDMA is of limited value once CKD is diagnosed, and I’m not sure why vets continue to use it after that point. Bun, creatinine, phosphorus, etc are much more useful in determining how to treat. Her CKD hovers right at the edge between 2 and 3.

 

[fionasmom]

My vet won't run SDMA, although if it is now attached to Antech, it will appear the next time that Jamie has a workup. She says that too many non kidney issues can affect it and had quite a laundry list of what those were.

 

[FeebysOwner]

I never had a vet who wanted to run SDMA either, but I suspect because it is a package deal from Antech, it is simpler to order the package.

As an aside, I was told if you only want to do part of the package, piecemealing it can become more expensive. This package contains Super Chem, CBC, T4, UA, and SDMA. When they couldn't get urine from Feeby for the UA portion, I was told that to exclude it and get charged for the rest, it would actually cost more. So, I paid for a UA in the package that didn't happen. Apparently, if you want to drag your cat to the vet multiple times within a 30-day period, they will try to get a urine sample at no additional charge.