The effect of blood drawing techniques and equipment on the hemolysis of ED laboratory blood samples.

Objective: The objective of this study was to identify venipuncture and blood draw factors associated with hemolysis (red blood cell damage) of ED blood samples.

Methods: A convenience sample of ED blood samples was studied for degree of hemolysis and phlebotomy technique using data obtained from surveys completed by ED nurses and/or ED clinical technicians. The questionnaires were submitted with each blood sample sent to the laboratory for diagnostic testing. The level of hemolysis per sample was designated by laboratory technicians. Completed questionnaires were gathered and analyzed. Chi-square analysis was used to determine significant relationships.

Results: During the 19-day study, 598 surveys were collected, and 76% (n = 454) were complete enough to be included in the analysis. The predominant technique for drawing blood in new venipunctures (n = 372) was by intravenous catheters (69% [n = 255]), versus straight needles (31% [n = 117]). Thirty-two percent of the samples had some degree of hemolysis; 13% were so hemolyzed that tests were canceled by the laboratory. Blood drawn through intravenous catheters resulted in significantly more hemolysis and test cancellation than that drawn with a straight needle (20% versus <1%, significant at P <.001). Intravenous catheter hemolysis was higher when a vacutainer was used versus a syringe (22% canceled versus 9% canceled, significant at P =.02).

Conclusions: Drawing blood through intravenous catheters was associated with significantly more hemolysis than drawing blood with straight needles. Using a combination of intravenous catheter and vacutainer caused more hemolysis than using an intravenous catheter with a syringe.