EVALUATION OF A TEST STRIP FOR MEASUREMEN T OF SPECIFIC-GRAVITY IN CANINE URINE

The specific gravity of 80 randomly chosen urine samples from healthy dogs without polyuria/polydipsia and from a few dogs with polyuria/pol ydipsia was measured by refractometry and by test strip method (sg tes t strip). Urine osmolality and pH were also measured and the urine sam ples were examined for the presence of glucose. In accordance with ear lier observations, there was an excellent correlation between the spec ific gravity determined by refractometry and the osmolality (r=0.98). The results obtained with the sg test strip correlated poorly with tho se obtained by refractometry (r=0.39) and poorly with the osmolality ( r=0.36). In 77.5% of the samples the specific gravity determined with the sg test strip differed by more than 0.005 from that determined by refractometry. After correction of the sg test strip results by +0.005 for urine pH greater than or equal to 6.5, this percentage decreased to 60%. The results for the refractometer and sg test strip were signi ficantly different (P<0.001). These results indicate that the sg test strip investigated is unsuitable for use to determination of the speci fic gravity of canine urine.