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Table 2 . Dipstick test parameters and related comments specific to cats and dogs [ 10 – 15 ] .
Parameter
Comments
Glucose Not present in the urine of healthy cats and dogs . Large amounts can indicate diabetes mellitus . Patients with kidney disease may have small amounts in their urine .
Ketones
Not present in the urine of healthy cats and dogs . Ketones appear when the body breaks down excessive amounts of stored fat to use as energy [ 10 ] . Ketones may appear in cases of diabetes mellitus or during prolonged periods of fasting / starvation [ 10 ] as well as in diabetic ketosis ( ketoacidosis ). In cats , other causes of ketonuria include lactation , hyperthyroidism and paracetamol toxicity [ 10 ] .
Blood Not present in the urine of healthy cats and dogs . Blood indicates bleeding in the urinary system , but this can be due to the way the urine sample was collected – if collected via catheterisation or cystocentesis , a small amount of blood can be present . Blood may also indicate infection , bladder stones , trauma or cancer [ 9 ] . Haematuria can be seen with haemolytic anaemia – as red blood cells are destroyed , haemoglobin ( protein ) is released [ 9 ] . Haemoglobin passes in urine even though there is no bleeding in the urinary system . Occasionally , blood can be seen on a dipstick test when there is muscle inflammation / injury , because damaged muscle fibres release myoglobin ( protein ) [ 9 ] .
SG Not accurately measured using a dipstick . Ideally , measure specific gravity using a refractometer . pH
Protein
Bilirubin pH indicates whether the urine is acidic or alkaline . Normal urine pH in cats and dogs is between 6.0 and 7.5 . Common causes of decreased ( acidic ) pH are diabetic ketoacidosis , renal failure , Addison ' s disease , being fed a high-protein or milk-based diet , and paradoxical aciduria ( acidic urine pH with metabolic alkalosis ) due to severe vomiting [ 11 ] . Uncommon causes of decreased pH are vomiting with chloride depletion or severe diarrhoea , fever , starvation or prolonged exercise [ 11 ] . However , for indications of medical conditions , additional tests would need to be carried out to confirm a diagnosis . Alkaline urine ( increased pH ) may be due to the patient having been fed a recent meal due to postprandial tide , delayed sample analysis or urinary tract infection ( UTI ) with urease-producing bacteria ( Staphylococcus spp ., Proteus spp .) [ 11 ] . Uncommon causes of increased pH include metabolic alkalosis , respiratory alkalosis ( e . g . hyperventilation due to the stress of travel or a veterinary visit ), or a diet rich in vegetables and cereals [ 11 ] . However , measuring pH using dipsticks can be inaccurate , so should be used only as a guide .
Not present in the urine of healthy cats and dogs . If protein is present it is indicative of kidney disease , but this is confirmed by running a urine protein-to-creatinine ratio ( UPC ), either inhouse or externally . Normal UPC in healthy cats is < 0.2 (< 0.4 in entire male cats ) and in dogs it is < 0.5 [ 12 ] . Other causes of proteinuria include glomerulonephritis , UTI / inflammation , pyrexia , systemic disease , neoplasia and myelomas . Protein concentration on dipstick tests is primarily affected by albumin [ 10 ] . The sensitivity and specificity of dipsticks for measuring albuminuria in cats are 90 % and 11 %, respectively . False-positive results are seen more frequently in cats than in dogs [ 10 ] . Stress , temperature extremes ( environmental or fever ) or strenuous exercise result in mildly increased proteinuria , which is temporary due to the increased permeability of glomeruli to plasma proteins [ 13 ] . Proteinuria can also result when there are high concentrations of haemoglobin , myoglobin and Bence – Jones proteins ( produced by neoplastic plasma cells ) in the blood [ 13 ] .
Not present in the urine of healthy cats but can be present in small amounts in the urine of healthy dogs . Abnormal amounts of bilirubin are suggestive of liver disease or red blood cell destruction [ 9 ] . Exposure to room air and delayed analysis may cause a false-positive result for bilirubin [ 9 ] .
Urobilinogen
In dogs and cats , urobilinogen does not offer additional information to bilirubin . The test is not specific enough to be diagnostically useful and should not be used as an indicator of disease [ 14 ] .
Nitrite Bacterial infections in dogs and cats do not cause increased levels of nitrite in the urine [ 14 ] . Therefore , unlike in a human urine test , the results of this test on cat or dog urine would be unsuitable for the detection of UTIs [ 15 ] .
Leucocytes
The leucocyte test using urine dipsticks has been developed using human leucocytes , not canine or feline cells [ 15 ] . In dogs , there have been many cases of false-negative results . In cats , there have been many false-positive results . Therefore , the reading cannot be considered accurate [ 15 ] .
Volume 38 ( 6 ) • December 2023
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