Urinary alpha-amylase and serum macroamylase activities in dogs with proteinuria

Activities of urinary alpha-amylase and serum macroamylase; concentrations of serum creatinine, immunocomplexes, and urinary protein; and patterns of proteinuria were determined in 35 dogs with proteinuria. Urinary alpha-amylase activity ranged from 37 to 4,031 U/L. Macroamylasemia was detected in 77.14% of dogs and the percentage of alpha-amylase precipitated ranged from 4.68 to 61.63. Serum alpha-amylase activity after immunoglobulin precipitation ranged from 654 to 6,390 U/L in 51.42% of the dogs; the values were higher than the reference limits. Concentrations of serum creatinine and immunocomplexes were higher than reference limits for 25.71 and 60% of dogs, respectively. Urinary protein concentrations ranged from 0.1 to 8.9 g/L. All the patterns of proteinuria were represented. Linear regression indicated correlations between urinary alpha-amylase activities, serum creatinine concentrations (P < 0.01), and concentration of immunocomplexes (P < 0.05). Mann-Whitney test indicated significantly higher urinary alpha-amylase activity (P < 0.01) and percentage of alpha-amylase precipitated (P < 0.05) in dogs with renal insufficiency.