| Diagnosis | Clarification of Cushing’s disease including differentiation between adrenal and pituitary forms |
| Material | Morning urine 1 ml |
| Execution | - Collection of morning urine day 1 = sample 1
- Collection of morning urine day 2 = sample 2
- Administration of dexamethasone on day 2: orally 3 x 0.1 mg/kg bdw throughout the day
- Collection of morning urine day 3 = sample 3
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| Parameter | Cortisol, creatinine |
| Method | Cortisol: Chemiluminescence assay (CLIA);
Kreatinine: photometry |
| Species list | Dog |
| Duration | Reporting of results on the day the sample is received (Mon–Fri) |
| Assessment | - Interpretation of the ratio of day 1 and day 2:
The ratios from the samples taken on days 1 and 2 are used to evaluate the probability of Cushing’s syndrome. - The sensitivity of the UCCR test is increased by performing repeated measurements. Positive or divergent findings should be verified using a low-dose dexamethasone suppression test. Negative findings indicate that Cushing’s syndrome is unlikely. However, if there is strong clinical suspicion, it is recommended to perform a low-dose dexamethasone suppression test.
- Interpretation of the ratio of day 3:
(An increased ratio on day 1 and day 2 is a prerequisite) > 50% of the average value of the first two samples indicate a cortisol-producing adrenocortical tumour. The presence of nonsuppressible pituitary Cushing’s disease is possible. < 50% of the average value of the first two samples indicate a pituitary-dependent Cushing’s disease or another disease which causes increased cortisol secretion (e.g. diabetes, stress, gastrointestinal diseases, diseases with protein loss).
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