SDMA VS CREATININE

The results of the kidney parameters of my 11 years old cat's blood tests are: CREA 1.6     SDMA 13 I'm confused because the creatinine is a little high but the SDMA is still normal. Isn't it usually the opposite? Based on my knowledge, the SDMA goes above the normal range before we see a rise of creatinine. Would you recommend to start feeding him with renal/k/d food? My vet didn't give me a clear answer. Thank you.

Hello!  Please would you confirm the units that the Creatinine is being measured in?

Hello!  Regardless of the Units, it is possible for creatinine to be a little raised, together with a normal SDMA.  This can happen in various sets of circumstances, for example if haemolysis (breakdown of blood cells in the sample) has occured, which might lower an SDMA result.  Or if muscle breakdown has recently occured in the body, eg after exercise, which might increase circulating creatinine.  Contradictions can also arise if the blood sample was taken post-prandially (after eating).  Blood tests are rarely considered in isolation, but as part of a clinical picture;  how hydrated the patient was at the time, what the situation was surrounding presentation, whether the results might be influenced by breed variation and so on. If a vet is unhappy with, or concerned about, a routine SDMA result, they will usually ask to repeat the test, either that day or further down the line.  If they ask for this, it's usually a good idea in order that they can ensure that they aren't dismissing anything that they should be concerned about.   Vets will usually ask for this if they need to. However, ideally you should feel that you can talk to your vet and it may be worth approaching them again or letting them know if you are unhappy with your understanding of any situation. I hope that this helps.

Ps if you search SDMA, kidney in our blog, you will find an excellent article covering these blood tests in more detail. All the best with your cats' kidneys for the future.

Thank you so much for your reply and for the important information. The units that the Creatinine is being measured in are mg/dL, and the reference range of our clinic is 0.8-1.4 mg/dL, which is not so clear to me, because in another clinic I've been to (with another cat), the Creatinine reference range was much higher (0.8-2.4 mg/dL)!  How come there's such a big difference between what considered to be a normal amount of Creatinine from clinic to clinic?...  Anyway, my vet is pretty happy with the current results because they are almost similar to the results of the previous test (that was done a year ago) - back then the Creatinine was the same -  1.6 mg/dL  and SDMA was 12 (only one unit lower than today), So my vet says that it means that the kidneys are in a stable condition. Unfortunately, he didn't do a urine test so I think that should be our next step.