Intravenous cannula can increase serum creatine kinase MB activity

INTRODUCTION: Different blood sampling methods may result in differing creatine kinase MB (CK-MB) results. The aim of this study was to assess the effect of 2 phlebotomy methods on the CK-MB level in serum samples of healthy adults.
METHODS: The study used 50 volunteers (20 females, 30 males) who were employees at Baskent University Hospital in Ankara, Turkey. The subjects were randomly assigned to the study group. Blood samples were collected with the most widely used equipment for each method being tested (20G intravenous [IV] cannula and 20G needle unit) to compare the effects of different methods of blood sampling. The mean values of CK-MB and creatine kinase (CK) activity were compared using a paired samples t-test.
RESULTS: The mean CK-MB activity was 14.4±4.1 U/L and the mean CK activity was 127.3±17.1 U/L in samples that were drawn with a 20G needle unit, while in samples drawn with a 20G IV cannula, the corresponding results were 19.3±3.8 U/L and 132.5±16.1 U/L (p<0.001 for both).
DISCUSSION AND CONCLUSION: The study results indicated that blood sampling using an IV cannula caused more mechanical injury to vessel endothelium than sampling with a needle unit. This translates to greater interference with CK-MB and CK activity when the cannula method is used. Blood sampling with a cannula led to elevated CK-MB activity.