Cat & Dog - Urine Tests

What is a urine analysis?

Urine analysis involves a collection of relatively simple tests that can be undertaken at the practice.  The tests assess the physical and chemical composition of the urine.  Abnormal results usually indicate that there is a disorder affecting either the kidneys and/or other parts of the urinary system.   Tests also provide information about potential problems in other organ systems or the presence of other problems, such as diabetes mellitus (DM, sugar diabetes).

Urine analysis, haematology and blood serum biochemistry tests together provide a fairly comprehensive health assessment of the patient.  Please see the relevant handouts.

How do I collect the urine?

We will provide you with a simple kit which allows you to catch a mid-stream urine sample and store it in the sterile container which is included.  If you have difficulty we may have to admit your animal in order to obtain a sample either by catheterisation or by other methods.  In the majority of cats and dogs a sample is easily obtained via the special kit although sometimes patience and perseverance are required.

What happens if I am unable to obtain a urine sample?

Please contact us.  If your pet will not co-operate we will admit him for a short time in order to obtain a sample.

What is involved in a urine analysis?

Broadly there are two types of test, physical tests and biochemical tests.

Physical tests involve:-

1. Assessment of colour and cloudiness (turbidity)
2. Measurement of specific gravity (concentration)
3. Measurement of pH (acidity or alkalinity)
4. Microscopic examination of cells and any sediment (solid material) present in the urine

1. Turbidity.  Normal urine is pale yellow to light amber and is generally clear to slightly cloudy.  Urine that is dark yellow suggests dehydration, while very pale yellow or clear urine indicates that the urine is not being concentrated by the kidneys.  Unusual colours (such as orange, yellow or brown) suggest that pigments are present in the urine and are an indication of other underlying problems.

Increased cloudiness can be associated with the presence of inflammation, blood or certain blood cells, crystals, mucus and/or other debris in the urine.  In these cases further tests are carried out to analyse the sediment.

2. Specific gravity (SG). The SG of the urine is a measure of its concentration.  The major function of the kidney is to maintain the body's fluid balance within narrow limits.  Excess fluid in the body is removed via the kidneys into the urine which becomes more dilute.  Conversely, if the body is dehydrated the kidney conserves water by reducing the amount excreted in the urine and the urine becomes concentrated.  Thus highly concentrated urine usually indicates some dehydration.  Whether specific treatment is necessary depends on other signs being present.  Often provision of drinking water is all that is necessary.  If the dehydration is severe, the patent may need to be hospitalised for fluid therapy by injection (a drip).

Normally the first urine sample passed during the day is the most concentrated.  If it is found that an animal repeatedly passes very dilute urine, particularly with early morning samples, further specialised tests are required.

3. pH.  pH is a measure of the urine's acidity or alkalinity.  Normal urine of a cat or dog ranges from mildly acidic to mildly alkaline.  Extremes of pH are more likely to be associated with disease.  Urine pH can be influenced by diet but is more often a reflection of the metabolic state.  It can also be an indicator of infection and underlying disease.  Regularly passed highly acidic urine (low pH) or alkaline (high pH) in itself needs investigation, since in such circumstances pets are more prone to certain types of stone formation and can be susceptible to bladder infections.

4.  Urine sediment.  Why is it examined?

Important information regarding health status can often be obtained from microscopic examination of the sediment.  Red blood cells, white blood cells, crystals, bacteria and tissue cells from other portions of the urinary system may be present.  Uncommonly parasite eggs can also be found.

• Red blood cells.  These may be present if the urine has had to be collected by techniques other than 'free flow'.  Large numbers can indicate bleeding which may be caused by conditions such as bladder stones, infections, coagulation (clotting) problems or trauma.
• White blood cells.  A small number of white blood cells may regularly be found in urine samples.  Large numbers generally indicate the presence of inflammation in the urinary system.  This is usually secondary to bacterial infection.
• Tissue cells.  An increased number of tissue cells usually indicates underlying inflammation, bladder stones or prostate problems (in the male dog).  If the cells are abnormal this may be an indication of cancer especially in the older animal.  Further tests may be necessary.
• Crystals.  These are one of the most common abnormal components of urine sediment.  They are often identified by their shape and colour.  Some crystals are associated with specific diseases and their presence may indicate the need for further tests.

Chemical analysis.  How is the chemical analysis of urine performed?

Today most chemical analyses of urine are carried out using a dipstick.  This is a small strip of plastic with a series of individual test pads.  Each pad measures a different chemical component of the urine and changes colour to reflect the amount of that substance in the sample.  The stick is dipped in the urine and after a specified time interval the colour is compared to a chart which indicates the amount of that chemical present.

What substances are tested for with a dipstick?

• Protein.  Protein in the urine is known as proteinuria and is usually abnormal.  Further tests may be necessary, particularly to test for the protein/creatinine ratio.
• Glucose.  Glucose is not normally present in the urine of healthy cats and dogs.  A positive reading is usually the first indication that the pet is suffering from sugar diabetes (diabetes mellitus).  However, small amounts of glucose in the urine may be caused by kidney problems.
• Ketones.  These result from fat breakdown.  They can occur when fat is being used to provide energy needs, as in the case of an animal suffering from sugar diabetes (diabetes mellitus).  Ketonuria can also occur in animals subjected to prolonged starvation.
• Occult blood.  The occult (hidden) blood test is a very sensitive test for blood in urine.  It is usually an indication of bleeding somewhere in the urinary system.  It can also indicate the presence of haemolytic anaemia resulting in haemoglobin (the red blood cell pigment) appearing in the urine.
• Urobilogen.  A detectable level of urobilogen in urine indicates that the bile duct is working with bile flowing from the gall bladder into the intestines.  This is normal.  Absence of urobilogen in the urine can indicate bile duct obstruction.
• Bilirubin.  This is a pigment that is produced in the liver and normally excreted from the body via bile.  Bilirubin is not found in the urine of healthy cats but small quantities are considered normal in canine urine.