A Review of Immune Mediated Transfusion Reactions

Abstract

Observed Technique Study Although the chi-squared analysis showed plastic vs metal cannulas as being significantly different, the logistic regression analysis showed this factor to be noncontributory. Logistic regression analysis revealed that the key variables were site of draw and fullness of the tubes. The antecubital fossa may be more favorable than the distal arm because of the faster flow due to its increased diameter and reduced resistance. In addition, smaller cannulas may be used for distal blood draws. The fullness of the tubes may affect hemolysis through the poorly understood effect of pneumatic tube transportation. Further investigation is necessary to elucidate the causes. The endpoint for hemolysis used in this study, though not quantifiable, is true to life. Samples are rejected not because their spectrophotometer reading indicates excessive hemolysis, but because the technician perceives it to be hemolyzed. Newer clinical chemistry analyzers have built in “hemolysis” flags that reject specimens that exceed a predetermined spectrophotometric standard for hemolysis. The barriers to reducing hemolysis include personal preference and feasibility. It is common in emergency medicine to draw blood samples from the distal arm when placing IVs to reduce the number of venipunctures. Emergency department personnel avoid placing the IV in the antecubital fossa because of the possibility of the catheter bending and obstructing infusions when the patient moves their arm. They are more likely to draw blood from the distal arm. Likewise, it may be difficult to fill a specimen tube despite one’s best efforts. Use of a standardized protocol for blood drawing can reduce the rate of preanalytic hemolysis by more than 7-fold. Hemolysis can best be reduced by drawing blood from the antecubital fossa and by completely filling the tube Acknowledgements