A case of floating gel.

Two unrelated patients underwent coronary angiography and a percutaneous intervention. At the end of the procedures, blood was collected (Vacutainer® SSTTM; BD) for troponin, creatine kinase (CK), and CK-MB isoenzyme analysis. After centrifugation with the Roche Modular Pre-Analytics system (Roche Diagnostics), pipetting error alerts were triggered on the aliquoting module of the Pre-Analytics system. Investigation revealed that the separator gel had migrated above the serum (Fig. 1A), preventing separation of the serum from the cells (Fig. 1B). A second collection obtained from each patient 2 h later manifested proper gel separation, and error-free measurements were accomplished.