Introduction
Alkaline urine in cats refers to urine that has a higher than normal pH, usually above 6.5 (normal range is 5.5-7). It is a relatively common issue seen in veterinary medicine. The aim of this article is to understand the causes of alkaline urine in cats, the associated risks, diagnostic tests, and potential treatments and prevention.
Normal Cat Urine pH
The typical pH range for normal cat urine is around 6.0 to 6.5 (PetMD). This falls within the slightly acidic range, as a neutral pH is 7.0. Most healthy cats will produce urine within this normal pH range.
According to Merck Veterinary Manual, the ideal urine pH is considered to be 6.3–6.6 in cats. This range allows for the urine to remain soluble and not cause problems like straining or inflammation during urination. As long as a cat’s urine pH falls within the normal range, it is not a cause for concern.
Diagnosing High pH
Cat urine pH above 7 is considered alkaline. The normal pH range for healthy cats is typically between 6.0-6.5, so a pH higher than 7 indicates an alkaline urine pH.
To test a cat’s urine pH, veterinarians typically use urine reagent test strips, also known as dipsticks. These strips turn color when dipped in a urine sample, allowing vets to compare the color change to a chart to determine the pH value. At-home urine pH tests are also available, using similar dipstick technology (PetMD).
Veterinarians may also send a urine sample to a lab for quantitative urinalysis if they need a highly precise pH measurement. Lab tests can detect pH changes as small as 0.1 units. But dipstick tests give a good general indication of alkaline urine above 7.
It’s important for cat owners to routinely monitor for high pH and catch it early before complications arise. Annual vet exams often include a standard urinalysis to screen for high alkaline urine along with other abnormalities.
Primary Causes
There are three main causes that can lead to high alkaline or pH levels in cat urine:
Struvite crystals – These crystals form in urine that is too alkaline. They clump together and can cause blockages in the urinary tract. According to source, struvite crystals typically form when the urine pH is over 6.5.
Bacterial infections – Infections in the urinary tract, especially with the bacteria Staphylococcus, can increase the pH and cause the formation of struvite crystals. Bacteria split urea in the urine into ammonia, which raises the pH. Treating the infection will help restore normal pH.[1]
Kidney or liver disease – If the kidneys or liver are not functioning properly, they may not be able to adequately filter toxins from the blood. This can lead to more alkaline urine. Serious systemic diseases need to be treated to help bring the pH back down.
Dietary Causes
Certain dietary factors can contribute to increased alkalinity in a cat’s urine. High protein diets, plant-based diets, and overall alkaline diets tend to produce urine with a higher pH in cats.
High protein cat foods can increase urinary pH, as protein metabolism produces alkaline byproducts. Feeding cats a diet very high in protein, especially low quality protein sources, is linked to higher urinary pH 1.
Plant-based and vegetarian diets also tend to make cat urine more alkaline. Cats are obligate carnivores and require high levels of animal-based protein. Plant matter produces more alkaline urine, so vegan and vegetarian diets may lead to an abnormally high urinary pH in cats 2.
Overall diet acidity or alkalinity affects urinary pH as well. Alkaline diets produce more alkaline urine. Acidic diets containing ingredients like cranberries, vitamin C, or DL-methionine can help lower urinary pH 1.
Other Contributing Factors
While diet and urinary tract infections are the most common causes of alkaline urine in cats, there are some other factors that can contribute to high pH levels:
Dehydration – When a cat is not drinking enough water, the urine becomes more concentrated which can raise the pH. Ensuring cats have access to fresh, clean water at all times can help prevent dehydration.
Medications – Certain medications like antibiotics, anti-inflammatories, and chemotherapy drugs can cause alkaline urine as a side effect. If a cat’s urine pH increases after starting a new medication, discuss alternatives with a veterinarian.
Stress – Stress causes the release of hormones like cortisol that affect urine pH. Reducing sources of stress through environmental changes, pheromones, or medication can minimize alkaline urine.
While these factors alone may not directly cause alkaline urine, they can contribute to the problem when combined with other issues. Monitoring your cat’s water intake, medications, and stress levels can help identify contributing causes of high pH.
Complications
High alkaline urine can lead to some serious complications for cats including:
Struvite Crystal Formation
One of the most common issues associated with high pH urine is the formation of struvite crystals. Struvite crystals form more readily in alkaline environments. These crystals can clump together to create stones or even “plug up” the urethra causing a dangerous blockage [1].
Urinary Tract Infections
Bacteria thrive in alkaline environments. The high pH allows certain bacteria like Staphylococcus to proliferate resulting in stubborn urinary tract infections [2].
Kidney Stones
In addition to struvite stones, cats with persistently high urine pH are also at risk for calcium oxalate stones forming in the kidneys. These stones can cause damage, bleeding, and even kidney failure [3].
Diagnostic Tests
There are a few different diagnostic tests vets can use to help determine the cause of high urine pH in cats:
Urine Culture
A urine culture analyzes a urine sample to check for bacteria that could be causing a urinary tract infection leading to high pH. The vet takes a sterile sample and grows any bacteria present to identify the type and best antibiotic treatment (Urinary pH Impact on Your Cat’s Health).
Bloodwork
Blood tests check kidney function, diabetes, and other systemic issues. High pH may indicate kidney problems allowing alkaline compounds to build up in the blood and exit through urine (How to Test the pH Levels of Cat Urine).
Imaging
X-rays, ultrasounds, or other imaging techniques visualise the urinary tract. This can detect bladder stones, tumors, anatomical defects, or other abnormalities possibly causing high urinary pH in cats (Urinary pH Impact on Your Cat’s Health).
Treatments
The main treatments for high alkaline urine pH in cats aim to reduce the pH to a normal level between 6.0 and 6.5. This is done through a combination of diet change, medications, and sometimes surgery.
The most common treatment is to switch the cat’s diet to a food formulated to promote more acidic urine. There are many commercial cat foods designed for urinary health that contain ingredients to lower urine pH. Feeding exclusively wet food also helps increase moisture intake, which dilutes the urine and reduces alkaline compounds.
Antibiotics may be prescribed by a veterinarian if a bacterial infection is causing the high pH. Common urinary tract infections in cats are often responsible for alkaline urine. Eliminating the infection helps bring the pH back down.
Surgery may become necessary if bladder stones have developed as a result of the high pH. Struvite stones form more easily in alkaline urine. The stones must be surgically removed by a veterinarian to prevent recurrent UTIs and damage to the urinary tract.
Prevention
There are several steps cat owners can take to help prevent high urine pH in cats:
Feeding a wet food diet is one of the most effective ways to help maintain a healthy acidic urine pH. Canned/wet cat foods have higher moisture content, which helps cats stay hydrated. Increased water intake leads to more dilute, acidic urine.1 Wet foods also tend to be lower in carbohydrates and minerals like magnesium and calcium that can raise urine pH.2
Making sure cats have access to plenty of fresh water is another key prevention step. Water fountains or multiple water bowls can encourage increased drinking. Diluted urine helps maintain an acidic pH within the healthy range.
Routine veterinary checkups to monitor urine pH are also recommended, especially for cats prone to urinary issues. Annual bloodwork and urinalysis allow vets to catch signs of high urine pH early before complications develop.
