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 comments are preliminary and based on early data from the use of SDMA in veterinary patients. We expect them to be updated as the veterinary profession gains further experience using SDMA alongside creatinine, the long-established marker in diagnosis and monitoring of canine and feline CKD." You can read the full statement here. (Specifics regarding the incorporation of SDMA results into CKD staging can be found at page 2.)
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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Theodor Geisel ("Dr. Seuss").