Dog Chronic Kidney Disease Staging and IRIS Guidelines

The IRIS staging system provides a standardized framework for assessing canine CKD severity and guiding treatment decisions.

Key Facts

The International Renal Interest Society (IRIS) staging system classifies CKD into stages 1-4 based on creatinine and SDMA
Stage 1 dogs have SDMA above 18 micrograms/dL but normal creatinine - subclinical disease detectable only by testing
Stage 2 involves mild azotemia (creatinine 1.4-2.0 mg/dL) with SDMA 18-35 micrograms/dL
Stage 3 is moderate azotemia (creatinine 2.1-5.0 mg/dL) with increasing clinical signs
Stage 4 involves severe azotemia above 5.0 mg/dL with overt uremic signs including nausea and weakness
Substaging for proteinuria and blood pressure identifies additional risk factors requiring management at each stage
Treatment recommendations are stage-specific - phosphorus restriction begins at Stage 2, fluid therapy at Stage 3-4

Welfare Considerations

IRIS staging provides a framework for progressive, proportionate intervention that matches treatment intensity to disease severity. Dogs with Stage 1-2 CKD can be managed primarily with dietary changes and monitoring. Advancing to Stage 3-4 without appropriate dietary management accelerates the welfare deterioration from uremia. Regular staging allows treatment to evolve as disease progresses.

What You Can Do

Request IRIS staging including both creatinine and SDMA from your vet for any dog with kidney disease
Understand your dog current IRIS stage and what treatment goals apply at that stage
Begin phosphorus restriction at Stage 2 as recommended - waiting until Stage 3-4 allows faster progression
Schedule recheck intervals appropriate to stage (quarterly for Stage 2, monthly for Stage 3-4)
Discuss the welfare goals of treatment at each stage to make informed decisions as CKD advances