Urinalysis

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Urinalysis is the examination of a sample of urine which can tell your vet a huge amount about the health of your dog. It is very useful as part of the diagnosis of AIHA. The urine sample can be taken in three different ways:

Directly from the bladder using a sterile needle & syringe through the abdominal wall which is the best way to avoid contamination from further down the urinary tract. This is called cystocentesis.
By catheter (a long thin flexible tube), gently passed into the urinary tract opening & into the bladder
Catching a sample of urine in a sterile container while your dog is passing it – it is best to try & get a sample mid-stream, rather than at the start or finish.

Urine samples can be examined for:

Cloudy urine can indicate infection, inflammation, mucous, crystals, debris. It can also smell bad & your dog may find urination painful. Further examination of cloudy urine from looking at the sediment will help to discover the cause.

Concentration (called specific gravity). Continuous passing of dilute urine can indicate kidney disease or another underlying disorder, although it is perfectly normal for dogs to pass diluted urine at some point during the day. Concentrated urine usually just indicates dehydration which can be corrected by drinking plenty of water, but can also signify an underlying disease requiring further investigation & IV fluid therapy. Regular checks on each sample of urine passed during a 24 hour period will reveal more information.

Acidity or alkalinity (called pH). Extreme acidity or alkalinity can indicate disease.

Examination of centifuged (spun) sediment under the microscope to look for cells & other material:
(a) Red blood cells are sometimes found in small numbers if the sample was collected by cystocentesis or catheterization. Large numbers of red blood cells can indicate bleeding, possibly caused by infection, clotting problems, injury, cancer, bladder stones etc
(b) White blood cells- Small numbers are usually insignificant. Increased numbers indicates inflammation of the urinary system which is usually secondary to a bacterial infection.
(c) Tissue cells – Increased numbers of tissue cells can indicate inflammation, bladder stones, or in male dogs, prostate problems. Any abnormal cells seen should be more closely examined (cytology) for possibility of cancer, especially in older dogs.
(d) Crystals – observation of shape and colour. Some crystals do not indicate disease at all & may even be present because of improper storage or leaving it too long before examining the sample. Observation of the type of crystals can determine whether they are present because of liver disease, bladder stones, kidney stones or even anti-freeze poisoning.
(e) Bacteria – Bacterial infection is a very common cause of inflammation of the bladder and even the kidneys too. If bacteria & inflammatory cells are seen in urine sediment, this normally points to a bacterial infection of the urinary system. A sample should be sent for culture to find out which antibiotic will treat the infection best. In the meantime, antibiotic treatment should be started straight away to prevent the infection getting any worse.When the culture results come back, the antibiotic may need to be changed. Dogs being treated for AIHA are always at higher risk of suffering from urinary tract infections.

Chemical Analysis (using a dipstick)
(a) Protein – high protein levels may indicate chronic infection, presence of pus & blood, inflammation of the kidneys, scar tissue presence in the kidneys, high blood pressure, lipemia. Very strenuous exercise can occasionally cause high protein in the urine.
(b) Glucose (sugar) – presence of glucose indicates diabetes or kidney disease. In AIHA treatment, drugs such as prednisone also may cause the presence of glucose in a urine sample.
(c) Ketones – high ketones usually indicates diabetes, but may occur after starvation.
(d) Blood -presence of blood can indicate bleeding in the urinary tract. Most importantly to AIHA it can indicate hemolytic anemia. Because red blood cells are being destroyed, they release hemoglobin, giving a positive result on the dipstick. Rarely, muscle injury & damage can also give a positive result.
(e) Urobilinogen – High levels can indicate hemolysis, especially with high bilirubin as well. High levels can also indicate liver disease, presence of blood parasites, toxic chemicals or toxic drugs. A low positive result means the bile duct is working properly, however a negative result doesn’t necessarily mean it has an obstruction, although this may need to be investigated further if any symptoms have been seen. Low or absent results can also be caused by by tetracycline & other antibiotics, or urine acidifying therapy. The pH of urine can also have an effect on the urobilinogen test result.
(f) Bilirubin – can be found in small quantities in healthy dogs, but high levels can indicate hemolysis due hemolytic anemia (from red blood cell destruction), especially with raised urobilinogen. High levels can also indicate liver disease , bile duct obstruction, tumors, toxic chemicals & drugs, infections (e.g. leptospirosis, toxoplasmosis), blood parasites, hepatitis & rarely, pancreatitis. Bilirubin is the substance which makes your pets eyes & mucous membranes look yellow or orange if abnormally high levels are present (jaundice).