The Added Value of Urinalysis: What Veterinarians May Be Missing
Diagnostic laboratory work for pets is performed in both illness and health to provide a holistic view of organ system function; core lab tests include haematology, blood chemistry, and urinalysis. In performing this collection of tests together, you're able to properly interpret the abnormalities and nuances that are key to making accurate diagnoses and excluding hidden illness. Because patients often have more than one disease, performing thorough testing helps to recognise all lab abnormalities and reduces tunnel vision and the risk of missing a diagnosis. When put into practice, however, many blood profiles do not include the paired urinalysis and, as a result, diagnostic efficiency and accuracy are hindered.
The Diagnostic Value of Urinalysis
Here are some of the possible benefits of including urinalysis within lab testing:
1. Interprets the Chemistry Profile
There are common changes in the chemistry profile (most notably, elevation in renal values) that cannot be properly interpreted without paired urine results. Without urine testing, the information and ultimate value of the chemistry testing are not maximised, and subsequent presumptions could lead to improper diagnoses, unnecessary treatments, or missed opportunities for intervention to improve patient wellness.
2. Interprets the Complete Blood Count
The importance of including urinalysis together with bloodwork extends to haematology, as well. For example, identifying blood loss in the urine could affect the interpretation of reported anaemia. Similarly, infection in the kidneys can result in significant white blood cell changes, which can be further investigated by urine sediment analysis.
3. Evaluates the Urinary Tract
Perhaps most transparent is the value of urinalysis in assessing the urinary tract itself: the concentrating ability of the kidneys, the identification of pathologic casts to support injury, the presence of inflammation to support cystitis, or the identification of crystals — which may reflect underlying stones or predispose cats, especially, to urinary tract obstruction. Given the myriad underlying conditions that may contribute to clinical signs, a thorough urinalysis is essential for the successful management of such cases.
4. Detects Diseases Earlier
Routine urinalysis testing in clinically healthy patients may also identify otherwise hidden abnormalities or concerning trends in data over time. Before there are clinical signs of kidney disease or telltale bloodwork changes, there may be earlier evidence for decreased renal concentrating ability or detectable protein loss in the urine that warrants further investigation. Urine sediment review may identify asymptomatic crystalluria, prompting an important diet change for proper management and prevention of clinical illness. Or, perhaps cellular atypia may be identified in the sediment as a result of underlying bladder cancer, and the early detection may allow for treatment that delays progression and the onset of discomfort and clinical signs.
Why Aren't More Urinalyses Performed?
Unfortunately, diagnostic bloodwork often does not include a paired urine sample for analysis. Likely, this reflects the additional effort of obtaining and analysing urine and, more notably, how the information obtained has been undervalued. There is also a lack of standardisation, training, and skill in the manual processing and interpretation of urinalysis in practice, and many clinicians rightfully lack confidence in achieving accurate and reproducible results. Thus, the value of urinalysis is jeopardised.
Tracking Advancements in Technology
Technological advancements now allow for automated urine chemistry strip reading and reporting. This not only frees up time for technicians, but it also provides an accurate reading of the reaction pads at the appropriate time. In addition, integrated software prevents transcription errors in recording results in patients' records. The technology that automates urine sediment analysis is far more impactful, enabling the fresh processing of urine with minimal technician time or training. According to the Journal of Veterinary Internal Medicine, this standardised process of urine sediment preparation has allowed for more thorough and detailed microscopic evaluation that can be used to review, share, and educate others.
With these advancements, the added effort of urinalysis falls largely on obtaining the urine sample. The details above argue whether it's worth the time, effort, and potential hassles. Cystocentesis is ideal, precluding contamination of the sample and allowing for culture if warranted, but even an owner-collected free-catch sample is worth analysing. If no abnormalities are detected, the information obtained proves useful for both bloodwork interpretation and the exclusion of many significant disease processes. If there are changes that could reflect contamination or warrant further testing, the investment of time and energy in re-evaluating this subset of samples via cystocentesis is justified.
Finding Success With Thorough Diagnostic Testing
Including the complete urinalysis in a patient's lab testing increases the diagnostic efficiency and accuracy of the bloodwork interpretation. It consistently helps to exclude or identify significant pathologic changes in the urinary tract itself while contributing to more sensitive and early detection of diseases affecting other organ systems. Especially for sick animals, urine testing is best performed in the clinic when possible, allowing for more accurate results as well as in-time feedback to guide subsequent testing (both lab and imaging) with the institution of appropriate therapy. Automated technology has made in-clinic urinalysis easier, more efficient, and more diagnostically sensitive. Performing such complete testing helps elevate the standard of care for patients, results in improved client satisfaction, and leads to better business outcomes.
