IRIS Stage 2 · Mild
IRIS Stage 2 kidney disease in cats: what it means
Creatinine is mildly raised. Many cats have few or no outward signs, though some drink and urinate more. This is often when diet changes and regular monitoring begin.
Please read first
These are reference ranges, not a stage. Only your vet can stage CKD — in a cat that is clinically stable and well hydrated, using results from at least two occasions and the whole clinical picture. The values below describe the range IRIS associates with Stage 2. A single test result in this range does not mean a cat “is” Stage 2.
The values IRIS associates with Stage 2
| Blood creatinine | 1.6 – 2.8 mg/dL (140 – 250 µmol/L) |
|---|---|
| SDMA | 18 – 25 µg/dL |
| Phosphorus target | 2.5 – 4.5 mg/dL |
Source: IRIS Staging of CKD (modified 2023) — iris-kidney.com; phosphate targets: 2026 iCatCare consensus guidelines.
What care often looks like
Every cat is different, and your vet will tailor care to yours. At this stage, care often includes:
- IRIS and ISFM guidance generally recommend a kidney (renal) diet from around this stage, introduced slowly. Studies link renal diets to longer, better lives for many cats with CKD.
- Keeping phosphorus within the IRIS target, first with diet and, if needed, a phosphate binder your vet prescribes.
- Checking blood pressure and urine protein (UPC), because treating high blood pressure or proteinuria can help protect the kidneys.
- Tracking weight, appetite and water intake at home, and rechecking labs on your vet’s schedule.
How long do cats live at Stage 2?
Many cats live for years after values reach the Stage 2 range. The pace varies a lot between cats, so your vet is the best person to talk with about your cat’s outlook.
Substaging: urine protein and blood pressure
IRIS also “substages” every cat with CKD by protein in the urine (UPC) and by blood pressure, because both affect care. These apply at any stage.
| UPC | Substage |
|---|---|
| < 0.2 | Non-proteinuric |
| 0.2 – 0.4 | Borderline proteinuric |
| > 0.4 | Proteinuric |
| Systolic (mmHg) | Substage |
|---|---|
| < 140 | Normotensive |
| 140 – 159 | Prehypertensive |
| 160 – 179 | Hypertensive |
| ≥ 180 | Severely hypertensive |
Questions to ask your vet
Ask your vet
- Is it the right time to start a kidney diet, and how should we switch?
- What phosphorus target are we aiming for?
- Does my cat’s blood pressure or UPC need treatment?
- When should we recheck?
Not sure where the numbers sit?
Type your cat’s creatinine and SDMA into the free Lab Decoder to see them on the IRIS reference bars.
Frequently asked questions
What does IRIS Stage 2 mean for a cat?
Creatinine is mildly raised. Many cats have few or no outward signs, though some drink and urinate more. This is often when diet changes and regular monitoring begin. Only your vet can stage your cat, using repeated tests on a stable, well-hydrated cat.
What creatinine level is IRIS Stage 2 in cats?
IRIS associates a blood creatinine of 1.6 – 2.8 mg/dL (140 – 250 µmol/L) with Stage 2 in cats, alongside an SDMA of 18 – 25 µg/dL.
What is the life expectancy for a cat with Stage 2 kidney disease?
Many cats live for years after values reach the Stage 2 range. The pace varies a lot between cats, so your vet is the best person to talk with about your cat’s outlook.
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