CREATINE-KINASE IN DOG PLASMA - PREANALYTICAL FACTORS OF VARIATION, REFERENCE VALUES AND DIAGNOSTIC-SIGNIFICANCE

In the dog, plasma creatine kinase (CK) activity was stable up to one week at +4 degrees C and one month at -20 degrees C. Activity was high er in serum than in plasma due to interference by CK from the platelet s. The reference values were determined in 232 dogs using the IFCC rec ommended method. There was a significant decrease in activity with age but no effect of sex. In adults, plasma CK exhibited a log-normal dis tribution ranging from 20 to 104 U per litre. In 510 dogs with various diseases, the overall sensitivity and specificity of CK determination were 40 per cent and 98 per cent, respectively. The numerous false ne gatives could result from the relatively short half-life of the enzyme , while the false positives could be due to secondary muscle damage.