Diagnostic Tests For Changes In Urinating Routines
We use one or more of these tests to determine the cause of your pet's medical problem.
A routine urinalysis monitors:
- Concentration (specific gravity)
- Acidity or alkalinity (pH)
- Nitrites (byproducts of bacteria)
- Protein (from damaged urinary tract lining cells and other disease)
- Red and white blood cells (bleeding or infection)
- Ketones (byproducts of chronic fever or advanced disease)
- Bile (overflow from liver conditions)
- Sugar (overflow from diabetes mellitus)
A sample of urine is spun in a centrifuge. The sediment is examined under the microscope for:
- Crystals (from the kidneys but more frequently the bladder)
- Casts (plugs of debris flushed down from the individual nephrons in the kidneys)
- Lining cells (from anywhere in the system but most frequently from the bladder)
- Sperm (from intact male pets)
- Blood cells
Bacteria naturally inhabit the urethra. A sample collected from a urinating pet may be contaminated by these bacteria. Samples collected via a urinary catheter are even more likely to be contaminated. The only way to obtain an uncontaminated urine sample is by "cystocentesis". For cystocentesis we clean the abdomen skin then pass a fine needle directly into the bladder to collect the sample for culture. It sounds dreadful but only takes a few minutes and doesn’t require an anaesthetic.
A variety of tests are used, including blood counts, measurement of kidney waste products such as urea and creatinine and measurement of mineral levels altered in kidney disease. Other blood tests help diagnose other causes of polyuria.
Plain x-rays can reveal bladder or kidney stones and other conditions. Contrast x-rays using material given intravenously outline the inside of the kidneys and the ureters while contrast, usually just air, introduced via a urinary catheter outlines the wall and contents of the bladder and urethra.
This non-invasive form of imaging is useful for three dimensional examination of the kidneys, bladder and prostate.
An endoscope is the best diagnostic aid for examining the lining of the urethra and bladder. Its use is generally restricted to larger female dogs.
Water Deprivation Test
When water is withheld, the concentration of urine increases. This test monitors whether the pituitary is releasing ADH hormone and whether the kidneys are responding to it.
Response To Synthetic ADH
An alternative to water deprivation. A pet's response to treatment with synthetic ADH is monitored.
A biopsy is undertaken only when other diagnostic tests have failed to determine the cause of a kidney disorder and when it is thought that the results are likely to improve the management of a kidney condition.
A variety of "flow" studies are available at Dick White Referrals.
Internal Digital Examination
Low tech but highly diagnostic, a digital rectal examination in medium to large dogs assesses the prostate and pelvic urethra. A digital vaginal examination assesses the condition of the urethral opening.
Blood In The Urine
Blood in the urine is always significant but has many sources. Blood with pain usually comes from the lower urinary tract. Blood without pain suggests kidney disease. Blood may come from other sources and may be a result of any of these conditions.
- BLADDER STONES
- KIDNEY STONES
- SEVERE URINARY TRACT INFLAMMATORY DISEASE
- WARFARIN POISONING
- AUTOIMMUNE HEMOLYTIC ANEMIA / THROMBOCYTOPENIA
- ESTRUS IN THE FEMALE
- SEXUAL OVEREXCITEMENT IN THE MALE
- INFLAMMATION, TUMOURS, TRAUMA TO THE GENITAL TRACT
The intensity of urine colour is directly related to its concentration. A morning flow is often darker than later in the day because of overnight concentration. Only clear yellow to amber is normal. Drugs, diet and eating a variety of plants can cause urine colour changes. Here are some colours and causes.
- highly concentrated
- liver disorders
PINK, RED , RED-BROWN
- blood or broken down red blood cells
- warfarin poisoning
- foods such as beetroot, blackberries
- broken down red blood cells
- liver disorders (bile)
- fat (lipid)