Comparison of a digital and an optical analogue hand-held refractometer for the measurement of canine urine specific gravity.

Urine specific gravity (USG) is used clinically as a measure of urine concentration, and is routinely assessed by refractometry. A comparison between optical analogue and digital refractometers for evaluation of canine urine has not been reported. The aim of this study was to compare a digital and an optical analogue hand-held refractometer for the measurement of canine USG, and to assess correlation with urine osmolality. Prospective study. Free-catch urine samples were collected from 285 hospitalised adult dogs, and paired USG readings were obtained with a digital and an optical analogue refractometer. In 50 dogs, urine osmolality was also measured using a freezing point depression osmometer. There was a small but statistically significant difference between the two refractometers (P<0.001), with the optical analogue refractometer reading higher than the digital refractometer (mean difference 0.0006, sd 0.0012). Paired refractometer measurements varied by <0.002 in 91.5 per cent of cases. The optical analogue and digital refractometer readings showed excellent correlation with osmolality (r=0.980 and r=0.977, respectively, P<0.001 in both cases). Despite statistical significance, the difference between the two refractometers is unlikely to be clinically significant. Both instruments provide an accurate assessment of USG in dogs.

Serum protein electrophoresis in 147 dogs.

Reference intervals for serum protein electrophoresis (SPE) were created from a group of 75 clinically healthy dogs and compared with SPE results obtained from clinical cases presented to the University of Bristol over an eight-and-a-half-year period. A total of 147 dogs, in which SPE had been performed, had complete case records available and thus met the inclusion criteria. Signalment and final diagnoses taken from the case records and SPE results were divided into normal and abnormal based on the newly established reference intervals. Cases were grouped according to the SPE protein fraction abnormalities and diagnosis using the DAMNITV classification system. Of the 147 cases, 140 (95.2 per cent) had abnormal SPE results. The most common protein fraction abnormality was decreased albumin (59.3 per cent) followed by a polyclonal increase in γ globulins (38.6 per cent). Decreased ß-1 globulins and increased ß-2 globulins were documented in 36.4 and 30.0 per cent of cases, respectively. The most common DAMNITV classification associated with abnormal SPE results was infectious/inflammatory disease, which was diagnosed in 79 of 140 cases (56.4 per cent). Monoclonal gammopathies were noted in eight dogs (5.7 per cent), and underlying lymphoproliferative disease was present in all cases where a diagnosis was achieved, including multiple myeloma (four dogs), splenic plasmacytoma (one dog), hepatic plasmacytoma (one dog) and lymphoma (one dog).

Transient hyperlipidaemia and anaemia in kittens.

Severe fasting hypertriglyceridaemia (5 to 126 mmol/litre) and anaemia (packed cell volume < 11 per cent) was observed in 12 litters of kittens around the time of weaning; the entire litter was usually affected, with significant mortality. Lipid analysis revealed marked increases in chylomicrons and moderate increases in very low density lipoproteins. Supportive measures for the treatment of anaemia and weaning on to a low fat diet resulted in rapid resolution of the clinical signs, anaemia and hypertriglyceridaemia. On recovery, plasma was collected from kittens from five of the affected litters, plus a number of closely related cats and unrelated cats living in the same environment. The lipoprotein lipase (LPL) activity was mildly but significantly lower in the previously affected kittens, their parents and unaffected siblings, than in the unrelated cats. The cats had normal apolipoprotein C-II function, normal heparin binding activity and no evidence of a circulating inhibitor to LPL. They did not have the LPL gene mutation reported previously in LPL-deficient cats from New Zealand.