UCCR: Why the Site of Urine Collection Can Affect the Diagnosis of Cushing's and Addison's in Dogs

Hospital stress, irregular schedules, and recent meals are minor details often considered irrelevant in clinical practice. However, when it comes to the Urinary Cortisol-to-Creatinine Ratio (UCCR), these factors can directly affect the reliability of the results and diagnostic interpretation.
Although it is a widely used test in the investigation of canine hypercortisolism, the UCCR has a limitation that is rarely discussed in practice: its high preanalytical variability, especially related to the environment where the urine is collected.
A study published in April 2025 in the American Journal of Veterinary Research, titled “Urinary cortisol-to-creatinine ratio in healthy dogs and dogs with hypercortisolism and conditions that mimic the disease,” evaluated the accuracy of the UCCR in healthy dogs, in dogs with hypercortisolism, hypoadrenocorticism, and in conditions that mimic these diseases, such as diabetes mellitus associated with hyperadrenocorticism (DMHA).
The study, conducted by Del Baldo et al., proposes a new reference range and reinforces important points regarding how and where collection should be performed, depending on the clinical suspicion.

Why does the collection site affect the result?

Cortisol is, by nature, a stress-response hormone, and its release is part of the hypothalamic-pituitary-adrenal axis—a system that is activated in response to any stimulus perceived as threatening by the body, including travel to the clinic, physical handling during the examination, and being in a hospital setting. For this reason, the collection site itself is capable of temporarily elevating cortisol levels, regardless of any ongoing pathological process.
Unlike tests in which the collection environment is of little relevance, at UCCR this factor can be decisive:

• Dogs with hypercortisolism already have elevated baseline cortisol levels;
• Hospital admission can add acute stress to this preexisting elevation;
• This makes it difficult to distinguish between what is a disease and what is a specific response to the environment;
• In dogs with hypoadrenocorticism, however, the lack of a response to hospital-related stress may, on the contrary, aid in the differential diagnosis.

When evaluated in conjunction with clinical suspicion and the context in which the sample was collected, this physiological response can directly guide the selection of the most appropriate protocol for each patient.

How to Interpret the UCCR Based on the Presumptive Diagnosis

Interpreting the UCCR requires a comprehensive evaluation that takes into account the numerical result, the context in which the sample was collected, and the clinical suspicion that prompted the test request. One of the key points highlighted by the study is that the same variable—stress—can have opposite effects, depending on the disease being investigated:

Suspected hypercortisolism (Cushing's syndrome) 

In such cases, home collection is recommended to prevent the stress of the hospital environment from artificially elevating the result and compromising the test’s sensitivity. 

Suspected hypoadrenocorticism (Addison's disease) 

In this case, hospital-based sampling is more appropriate. Since these patients are unable to elevate their cortisol levels even in response to a stressor, the hospital environment itself can help highlight this inability to respond, aiding in the differentiation from similar conditions, such as DMHA.

Would you like to request a UCCR test?

Why does the context of data collection matter just as much as the result?

Due to the high preanalytical and analytical variability described in the study, the UCCR should not be interpreted in isolation as a confirmatory test. Its most appropriate role is that of a screening test—a starting point that guides further investigation—rather than a standalone diagnostic conclusion.
In clinical practice, the value of a hormonal test lies not only in the isolated number but in the relationship between the result, the conditions under which the sample was obtained, and the clinical suspicion that prompted the investigation.
Ignoring the context of sample collection can lead both to falsely elevated results in stressed patients without actual hypercortisolism and to misinterpretations in cases of hypoadrenocorticism, underscoring the importance of documenting this detail on the test request form.

Do you need help interpreting your UCCR results?

Where can I get hormone tests done?

At Hormonalle, we measure urinary cortisol (UCCR) using the chemiluminescent immunoassay (CLIA) method. This combination of validated technology and specialized technical interpretation contributes to more accurate hormonal diagnoses and more reliable clinical decision-making across the field of veterinary endocrinology.

Specializing in veterinary endocrinology, Hormonalle offers a comprehensive range of hormonal tests for dogs, cats, and horses, supporting veterinarians in the diagnosis of endocrine diseases in small animals.

Access the full study

The scientific article on which this content is based is available at:

Urinary Cortisol-to-Creatinine Ratio in Healthy Dogs and Dogs with Hypercortisolism and Conditions That Mimic the Disease

American Journal of Veterinary Research, 2025. (article link)

Bibliographic reference

DEL BALDO, F. et al. Urinary cortisol-to-creatinine ratio in healthy dogs and dogs with hypercortisolism and conditions that mimic the disease. American Journal of Veterinary Research, Apr. 14, 2025. DOI: 10.2460/ajvr.25.01.0020.