Why kidney diagnostics matter for dogs and cats
How UPC analysis helps detect kidney disease early and monitor treatment progress.
Kidneys are the organ where waiting for symptoms fails worst. By the time a cat or dog shows the classic signs of chronic kidney disease — drinking constantly, urinating large volumes, losing weight, going off food — roughly two thirds of functional kidney tissue is typically already gone. That damage does not come back. Everything useful that can be done for a kidney patient depends on finding the problem before it announces itself, and that is a diagnostic question, not a symptom-watching one.
Chronic kidney disease is one of the most common serious illnesses in older cats in particular. It is also one where good management genuinely buys years of comfortable life — but only if it is caught in the earlier stages.
## What the tests actually tell us
A kidney work-up is not one test. Each piece answers a different question, and any single result on its own is easy to misread.
**Urine specific gravity** is often the first thing to change. Healthy kidneys concentrate urine; failing ones cannot, so the urine becomes progressively more dilute. Dilute urine paired with a rising blood value is much more meaningful than either alone — and this is why we ask for a urine sample rather than blood only, and why owners are sometimes surprised that we do not simply take blood and be done.
**Creatinine and urea (BUN)** are waste products the kidneys clear. They rise as filtration falls, but they are late markers: creatinine typically does not leave the normal range until around three quarters of function is lost. A normal creatinine is not proof of a healthy kidney.
**SDMA** is a newer blood marker that rises earlier than creatinine and is less affected by how much muscle the animal has — useful in a thin old cat, where creatinine can look reassuringly normal precisely because there is little muscle left to produce it.
**The UPC ratio — urine protein to creatinine.** This one deserves its own paragraph. Protein leaking into urine is both an early sign of glomerular damage and, independently, a driver of further damage: the protein loss itself injures the kidney, which is why the value guides treatment rather than only measuring it. UPC is one of the strongest predictors we have of how a kidney patient will do over time, and it is the test most often missing from a work-up done elsewhere. Our laboratory in Batumi runs it in-house.
**Blood pressure** matters because hypertension and kidney disease drive each other, and untreated high blood pressure damages the kidneys, the eyes and the heart. In cats it can cause sudden blindness from retinal detachment — a genuinely preventable outcome that is easy to miss if nobody measures.
**Phosphate, potassium and calcium** shape both prognosis and diet. Phosphate control is one of the interventions with the clearest evidence behind it.
**Ultrasound** shows structure where bloods show function: kidney size and shape, stones, obstruction, cysts, tumours, changes suggesting infection. A blocked ureter and end-stage chronic disease can produce similar blood results and need completely different treatment — imaging is what separates them. We do abdominal ultrasound on site.
## Signs worth acting on
Some of these are subtle enough that owners often only recognise them in hindsight.
Drinking noticeably more, or a cat that starts drinking from taps and glasses when it never did. More urine, or larger clumps in the litter tray. Weight loss over months, especially with a poor coat. Reduced appetite, or fussiness in a cat that used to eat anything. Vomiting, bad breath with an unusual smell, weakness or lethargy. In dogs, urinating overnight when they used to sleep through.
And two that mean today, not next week: **not urinating at all, or straining without producing urine** — in a male cat this is a blocked bladder and an emergency measured in hours — and **urine the colour of tea or cola**, which suggests destroyed red blood cells and in this region is often tick-borne babesiosis attacking the kidneys.
## Who should be screened, and when
Screening is cheap relative to what it prevents, and there are clear groups where it is worth doing before anything is wrong.
Cats from around seven years old, annually, and twice yearly past ten or eleven. Any older pet before an anaesthetic — kidney function changes both the drugs we choose and the fluid plan, and this is a routine part of pre-operative testing for good reason. Pets on long-term medication that is cleared by the kidneys. Breeds with inherited kidney disease, including Persian and related cats with polycystic kidney disease. Any pet that has had an episode of acute kidney injury, dehydration or a urinary blockage. And any animal with unexplained weight loss or a changed drinking pattern, at any age.
If a first result is borderline, the answer is usually to repeat it in a few weeks rather than to act or dismiss it. A single number is a snapshot; two numbers are a direction, and the direction is what matters.
## What happens if we find something
This is where early detection earns its keep. Chronic kidney disease cannot be reversed, but its progression can often be slowed substantially, and the tools are unglamorous and effective: a diet formulated for reduced phosphate and appropriate protein, guaranteed water intake, phosphate binders where needed, treating high blood pressure, reducing protein loss where UPC shows it, and treating the anaemia and nausea that make these patients feel unwell. Many cats diagnosed in the earlier stages live years, comfortably.
That sentence is only true for patients found early. The same disease found at the point where the animal has stopped eating is a different, shorter conversation.
If your cat is over seven, or your dog is drinking more than it used to, a blood and urine screen takes one visit and a small sample. Call us in Batumi and we will tell you exactly what the panel includes before you commit to anything.