Cat Health • Kidney

Kidney disease in cats: what are the early signs?

Chronic kidney disease can develop gradually, and early changes may be subtle. Increased thirst and urination, weight loss and appetite change are common clues.

Veterinarian reviewedUpdated Aug 20, 2026
Quick answer

Do not rely on one symptom or one blood value. Kidney assessment combines history, physical examination, blood tests, urinalysis, blood pressure and sometimes urine protein measurement or imaging.

Common early signs

  • Drinking more water
  • Producing larger amounts of urine
  • Gradual weight or muscle loss
  • Reduced or selective appetite
  • Nausea, vomiting or constipation
  • Lower activity or poor coat quality

Why can kidney disease be hard to notice?

Cats compensate well, and owners may not notice gradual changes until substantial kidney function has been lost. Trends in body weight, muscle condition, urine concentration and laboratory values can therefore matter more than a single snapshot.

What tests are commonly used?

Veterinarians commonly evaluate creatinine, BUN, SDMA when appropriate, phosphorus, electrolytes, red blood cell status, urine specific gravity, urine protein and blood pressure. IRIS staging helps organize chronic kidney disease after diagnosis and supports treatment planning.

What can treatment include?

Management depends on stage and individual problems. It may include a therapeutic renal diet, maintaining hydration, controlling phosphorus when indicated, treating hypertension or proteinuria, managing nausea and maintaining calorie intake and body condition.

Important: A “kidney-support” supplement does not replace staging, renal nutrition, blood-pressure control or treatment of complications.

Related VetWel guides

Read why a cat may drink more water, loss of appetite in cats and preventive checkups.

Veterinarian Nazif Oben Akşemsettinoğlu
Veterinarian Nazif Oben AkşemsettinoğluVetWel Founder & Veterinary Consultant