1. Regarding SDMA generally: "Clearly SDMA has utility for the diagnosis and management of dogs and cats with renal disease. But, as with any promising new biomarker, there is a need for additional studies." You can read the full statement here:
2. Regarding the incorporation of SDMA results into CKD staging: "These recommendations are based on current state of knowledge where SDMA appears to be a more sensitive indicator of early stage CKD in the dog and cat. The specificity of SDMA has not been tested in large scale prospective studies to enable all the factors influencing specificity to be understood. We expect these guidelines to be updated with further recommendations that will assist the use of SDMA in the diagnosis and staging of CKD in the future." You can read the full statement, and the latest staging recommendations here.
It is noteworthy that at least one study indicates that SDMA utility may be compromised in diabetic cats but, as noted earlier, SDMA is still at an early stage, and more research is needed.
3. In late 2019, IRIS republished their CKD treatment recommendations with fully integrated recommendations for how to include SDMA results in treatment plans. The recommendations are here.
IDEXX Labs is currently offering this test as part of certain blood panels at no additional charge, so please ask your vet if it could be appropriate for your feline or canine companions.
* Creatinine is a normal by-product of muscle activity, and is normally removed from the body by the kidneys. If muscle is lost, (which often happens in older patients, and in patients with Chronic Kidney Disease), then less creatinine is produced. Therefore, creatinine levels in CKD patients could be falsely low (i.e.: closer to normal) than they would be if muscle mass were normal, thereby giving the impression that they kidneys are functioning better than they really are.
A study published on February 21, 2019 which examined Glomerular Filtration Rate (GFR)* in 97 dogs, concluded that the overall performance of creatinine and SDMA, as markers of reduced GFR were similar. But the study also states that use of SDMA as an adjunct to creatinine may provide additional value for diagnosis of decreased GFR. More research is warranted. Pelander L, Häggström J, Larsson A, et al. Comparison of the diagnostic value of symmetric dimethylarginine, cystatin C, and creatinine for detection of decreased glomerular filtration rate in dogs. J Vet Intern Med. 2019; 1-10. https://doi.org/10.1111/jvim.15445
* Glomerular filtration rate (GFR) is the volume of fluid filtered by the kidneys over a specified period of time, and is directly proportional to kidney function i.e.: higher GFR equals more kidney function, lower GFR equals less kidney function.
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