Effects on Red Blood Cell Labeling Protocols due to USP 797 revisions.

2738 Objectives Effective October 1, 2014 the state of Florida recognized the revisions that United States Pharmacopeia (USP) applied to USP Chapter 797 on June 1, 2008, restricting the amount of extractions from a sealed source.These revisions which are mandated at an individual state level,can directly affect nuclear medicine technologist’s protocols when conducting studies involving red blood cell labeling. The purpose of this study is to explore how the revisions of USP 797 affect the in-vitro red blood cell labeling method. Methods The current proposed standards restrict the number of penetrations into a sealed vile to only two. In red blood cell labeling, the in-vitro method requires the technologist to pierce the tagging vial five times and is therefore considered a medium-risk compounding sterile preparation (CSP).The revisions to USP 797, restricts the use of the in-vitro RBC labeling method unless the nuclear medicine department establishes an ISO Class 5 clean room for its preparation. The alternative method is in-vivo RBC labeling. A comparative analysis of the two methods was performed to evaluate tagging efficiency and its effect on image quality. Results In a study of 72 patients having a cardiac blood pool study, activity not bound to RBC for in-vivo was between 4.7-99.2% versus in-vitro of 1.3-8.7%. In the in-vivo study the images were of good quality in 35% of the patients, while the in-vitro study produced good quality images in 100% of the patients. The accepted tagging efficiency of in-vivo labeling ranges between 60-90%, while in-vitro labeling has a 98% tagging efficiency. Conclusions Although RBC labeling can be achieved without the use of in-vitro tagging method, the overall quality of the study is affected with alternative methods.The revisions of USP 797, eliminates the ability of a technologist to perform the in-vitro procedure without an ISO Class 5 clean room and can by quite expensive. Devoid of significant changes to protocols, the quality of images in RBC labeling studies will be diminished, potentially compromising patient diagnosis.