Acute kidney injury in dogs: IRIS grades without azotaemia
7-year-old Labrador operated on for a cruciate ligament rupture. He is receiving meloxicam and has had vomiting and low water intake after surgery. Urine output is normal.
| Parameter | Result | Reference |
|---|---|---|
| Baseline creatinine (pre-surgery) | 0.9 mg/dL | 0.5–1.5 |
| Creatinine at 48 h | 1.4 mg/dL | 0.5–1.5 |
| Urine specific gravity | 1.016 | > 1.030 |
| Sediment | Occasional granular casts | — |
How is this dog's renal status classified?
chevron_right Show answer and explanation
A. There is no kidney injury: creatinine remains within the reference interval
Creatinine is not linear with filtration: a 50% rise in 48 h reflects a significant drop in filtration, even if it does not exceed the upper limit.
B. IRIS grade II acute kidney injury
Grade II corresponds to creatinine of 1.7–2.5 mg/dL. At 1.4 mg/dL it is grade I.
C. IRIS stage 1 chronic kidney disease
CKD staging requires a stable patient and persistent values. A change within 48 h after an NSAID is an acute process and is graded with the AKI system.
D. IRIS grade I acute kidney injury (non-azotaemic, non-oliguric): stop the NSAID and correct volume status
Correct. IRIS considers an increase in creatinine of ≥ 0.3 mg/dL within 48 h to be grade I AKI even if still within range, especially with evidence of injury (poorly concentrated urine, casts). This is the time to act: withdraw the nephrotoxin and rehydrate.
lightbulb Key takeaway
IRIS AKI grades by creatinine: I < 1.6; II 1.7–2.5; III 2.6–5.0; IV 5.1–10.0; V > 10 mg/dL, each subgraded as oliguric or not and by need for renal replacement therapy. Always compare with the patient's own baseline creatinine.
References: IRIS Grading of Acute Kidney Injury (2016)
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Updated: October 31, 2026 · Educational content for veterinary professionals. It does not replace current clinical guidelines or the judgement of the attending veterinarian.