Diagnosis of CKD

CKD diagnosis is based on three diagnostic methods: clinical examination, laboratory analysis of blood and urine, and imaging techniques such as X-rays and ultrasound. Diagnosis is based on the cumulative findings of all techniques.

The International Renal Interest Society (IRIS) publishes guidelines for classifying chronic kidney disease (CKD) into four stages. These precisely define which parameters should be determined and which parameters are indicative of particular stages (“staging” is classification of an affected cat into a specific CKD stage on the basis of the given criteria). Blood pressure and proteinuria are also taken into account. The most important factors for classification are the level of creatinine in the blood and the “SDMA test” (→ see Blood tests). To date, the most important criterion for CKD evaluation has been the level of creatinine in the blood. Levels of urea and phosphate in the blood are also important in CKD diagnosis.

Relevant tests in kidney disease
Relevant tests in kidney disease

1. Clinical examination

Cats are examined to determine their general condition, age, sex, breed, pre-existing conditions, medication and acute health problems. Their temperature is then measured, the visible mucous membranes are examined for paleness and they are examined for dehydration, emaciation, bad breath and eye health. Usually the vet will also feel for their kidneys (kidney palpation) and examine them for pain, size and palpable superficial changes. Symptoms are the main focus.


2. Laboratory tests

2.1 Blood tests to diagnose CKD

  • Creatinine
  • SDMA test
  • Urea
  • Phosphate

2.2 Urine analyses

  • Specific gravity (SG) of urine
  • Urinary protein levels (UPC)

2.3 Further blood tests

  • Calcium
  • Calcium and sodium
  • Erythrocytes and haematocrit
  • Glomerular filtration rate (GFR)


3. Further tests

3.1 Radiological tests

  • X-ray
  • Ultrasound
  • CT and MRI

3.2 Measurement of blood pressure