The Impact of Pre-hospital Blood Collection on Time to Laboratory Test Results and Emergency Department Length of Stay

Purpose:
The purpose of this prospective, controlled study was to determine the impact of obtaining blood specimens in the pre-hospital setting versus drawing specimens in the emergency department and the effect on emergency department total length of stay.

Background/Significance:
Few studies exist that evaluate the use of emergency medical services (EMS) to expedite door to laboratory result time. By drawing blood specimens when intravenous lines (IVs) are started pre-hospital, laboratory result times could dramatically decrease. Our research group hypothesized that patients who had blood samples collected prior to hospital arrival would have statistically and clinically significant reductions in door to laboratory result times and overall shorter ED lengths of stay.

Methods:
This study was a retrospective observational design and was a convenience sample. 101 patients enrolled in the study were assigned to either the pre-hospital blood collection group (n=58 or the hospital blood draw group (n=43) Clinical laboratory personnel were blinded to the study groups. We collected the following data: time of patient arrival, time blood sent to lab, time blood received in lab, time results received, time of patient disposition, total ED length of stay, and any abnormalities of the specimen (hemolysis) requiring collection of a new specimen. Statistical analysis included a Student's t-test for all of the dependent variables. Significance accepted at the 0.05 level.

Results:
Patients in the experimental group had door to results times for complete blood counts that were an average of 26 minutes shorter than times for patients in the control group (p<0.004). Mean door to results times for serum chemistry studies were 28 minutes less than those of controls (p<0.02). There was no significant difference between groups in the number of clotted or hemolyzed specimens requiring repeat blood collection.

Conclusions and Implications for Practice:
Collecting blood samples in the pre-hospital setting, at the time of intravenous catheter insertion, significantly shortens time to laboratory results, is not associated with an increase in hemolyzed or clotted specimens, and may decrease overall ED length of stay.