RenalTech™ – The Mars / VCA Kidney Test Algorithm

Ron Hines DVM PhD


My comments in Purple Follow-up emails in Green

Emails Received:

September 23, 2020

My cat won’t eat wet food [he insists on dry kibble]. He was willing to eat Royal Canin A for 6 months, and then wouldn’t. He ate Royal Canine S for a while and then stopped. He now likes Purina NF and Blue Buffalo Kidney and Mobility. I mix them to make a new ratio for variety–some days 80% NF to 20% Blue, some 90/10. The calories per cup are very different. I favor the Purina NF. When he gets tired of one, I start over.

RC A is 0.6% maximum phosphorus. Royal Canine S is 0.55 maximum phosphorus. Purina NF is 0.44 maximum phosphorus. Blue Buffalo K+M is 0.4% minimum phosphorus. The bags of BB K+M with a vertical orange strip are 0.7% maximum phosphorus. I wrote to them, BB said they use a 0.4% minimum to 0.7% maximum because they can’t accurately tell the phosphorus level other than by testing each batch. It is said, probably by the renal cat food manufacturers, that if a cat eats a renal diet at about .5% Phosphorus vs. 1 to 3 percent in a commercial food, a binder may not be needed. Fancy Feast is around 2 percent. My cat’s blood phosphorus level tested at 4.1 once and at 4.6 once while on the renal diets.

I prefer giving the 200 mg Con Seal AIH phosphate binder because it is chewable while Phos-Bind powder from Rx Vitamins being a powder is hard to get to stick on his kibble. My vet suggested lanthanum, phosphate binder. I found one article that says lanthanum can bind/stick to arteries–just one mention of this. Most people in the group use Phos- Bind. Some use Epakitin. Epakitin is calcium-based [possibly a bad thing?]. If and when I use a PB I will give the least amount possible using P testing and panels every 3 months. wise. The Antech phosphorus scale upper limit is far over the IRIS recommendation of treating at 4.0 and 4.6 P in CKD cats. Antech’s P normal or typical range is: 2.4 to 8.2 P !!! 8.2 is far above 4 to 4.6 for use of a binder. Vets and owners could miss that. 

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