Abnormal flotation of separator gel in blood test tubes in the hemodialysis patients

Abstract

Objectives: Serum-separating tubes (SST) are used in medical clinical chemistry tests requiring blood serum. Blood density is mainly dependent on the total protein concentration. Aim of this study to investigate, whether high protein content due to dehydration during hemodialysis can cause laboratory error with the abnormal flotation in blood tubes. Methods: After examining post hemodialysis (HD) blood samples of three cases with ESRD we investigated the effect of adding bovine albumin to the test tubes to determine whether an increment in protein concentration result in abnormal flotation of separator gel in blood samples obtained from healthy volunteers. Results: Serum total protein levels were markedly increased in blood samples of all 3 cases. In tests using blood samples from healthy volunteers supplemented with bovine albumin to increase the protein load, the test tubes having an albumin concentration greater than 16 g/dl displayed an abnormal flotation of separator gel similar to those we observed in post-HD samples from our cases. Conclusion: Increased protein load, probably caused by Intradialytic hypotension due to dehydration, induces the observed abnormal flotation of separator gel in serum tubes in these cases. Our findings emphasize the importance of visual control of serum tubes to prevent abnormal flotation in blood samples.