IRIS Stage 1 · Non-azotemic
IRIS Stage 1 kidney disease in cats: what it means
Creatinine is in the normal range, but there is other evidence of kidney change — such as poorly concentrated urine, abnormal imaging, protein in the urine, or a persistently raised SDMA. Many cats live a long time at this stage.
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 1. A single test result in this range does not mean a cat “is” Stage 1.
The values IRIS associates with Stage 1
| Blood creatinine | < 1.6 mg/dL (< 140 µmol/L) |
|---|---|
| SDMA | < 18 µg/dL |
| Phosphorus target | No specific IRIS target at this stage |
At Stage 1, creatinine is below 1.6 mg/dL. Vets identify kidney changes through other findings, such as urine that isn’t well concentrated, protein in the urine, changes on imaging, or an SDMA that stays above 14 µg/dL on repeat tests.
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:
- Looking for and treating anything that may be affecting the kidneys, such as infection, stones, high blood pressure or medicines that stress the kidneys.
- Making sure fresh water is always available, and many vets encourage wet food to help with hydration.
- Rechecking blood, urine and blood pressure on a schedule your vet sets, so changes are noticed early.
- IRIS does not set a phosphorus target at this stage. Your vet will decide whether any diet change is helpful yet.
How long do cats live at Stage 1?
Many cats live for a long time with Stage 1 values. Regular monitoring helps you and your vet notice changes early.
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
- What made you suspect kidney changes if creatinine is normal?
- Should we look for an underlying cause?
- How often should we recheck blood, urine and blood pressure?
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 1 mean for a cat?
Creatinine is in the normal range, but there is other evidence of kidney change — such as poorly concentrated urine, abnormal imaging, protein in the urine, or a persistently raised SDMA. Many cats live a long time at this stage. Only your vet can stage your cat, using repeated tests on a stable, well-hydrated cat.
What creatinine level is IRIS Stage 1 in cats?
IRIS associates a blood creatinine of < 1.6 mg/dL (< 140 µmol/L) with Stage 1 in cats, alongside an SDMA of < 18 µg/dL.
What is the life expectancy for a cat with Stage 1 kidney disease?
Many cats live for a long time with Stage 1 values. Regular monitoring helps you and your vet notice changes early.
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