A blue result in color-changing cat litter commonly suggests that the urine pH is higher or more alkaline than the product’s reference range. It does not prove that a cat has a urinary tract infection or bladder stones. Confirm the result with fresh litter, watch for symptoms and contact a veterinarian if the color repeats.
Why can urine produce a blue result?
Health-monitoring litter contains pH-sensitive indicators. When urine activates the indicator, the color changes according to the urine’s acidity or alkalinity. Diet, hydration, medication, sample age and health can all influence the result.
What to do after seeing blue
- Check that the box was free of cleaning-product residue.
- Observe a new, fresh clump under neutral lighting.
- Compare it with the current Purrify package chart.
- Record the color and the time in the Purrify app.
- Watch your cat’s behavior and urine output.
Symptoms that need veterinary attention
- Straining or repeated trips to the box
- Crying or obvious discomfort while urinating
- Only small drops of urine
- Visible blood
- Urinating outside the box
- Vomiting, hiding or loss of appetite
If a cat cannot pass urine, seek emergency veterinary care immediately. Urinary blockage can become life-threatening, especially in male cats.
Does blue mean a UTI?
No. Higher urine pH can occur for several reasons, and some cats with urinary disease may not show a blue result. A veterinarian may use urinalysis, urine culture, imaging and a physical examination to determine the cause.
How Purrify helps
Purrify is designed for trend awareness: a plant-based, fast-clumping litter that makes it easier to notice and record changes during everyday scooping. See the complete cat urine pH color chart and our guide to UTI detection limitations.
Frequently asked questions
Should I change my cat’s food after a blue result?
Do not make a medical diet change based only on litter color. Ask a veterinarian who can interpret the result with your cat’s history and testing.
Can an old clump turn blue?
Color may look different as a clump dries or under colored lighting. Follow the recommended reading time and check a fresh result.
Medical disclaimer: This article is educational. Purrify does not diagnose urinary disease.