Root cause analysis of laboratory delays to an emergency department

The Q-Probes study has identified benchmark interinstitutional laboratory median turnaround times (TAT) of 25 rain for hemoglobin and 36 min for potassium. Our objectives were to measure the emergency department (ED)/laboratory TAT and other relevant laboratory processing and reporting times, and to identify root causes of laboratory delay. A flow chart was developed for the ordering, collecting, analyzing, and reporting of laboratory results. Time intervals were prospectively recorded for complete blood count (CBC) and K⁺ in a cross-sectional study, using the flow chart, and defined as follows: TAT was the interval from blood draw (BD) to ED report; BD time was the interval from order processing to BD; and order processing time was the interval from physician ordering to the unit coordinator processing the orders. Median times with interquartile ranges are reported. CBC TAT was 38 min (29-51.5), and K⁺ TAT 58 min (45-76.5). Order processing time was 7 min (4-15). The laboratory assistant BD time was 17 min (8-30) for CBC and 15 min (7.75-32.25) for K⁺ as compared to 0 min for a nurse, yet the venipuncture method (laboratory assistant technique) had a recollection rate of 1% (1/93) due to hemolysis vs. 20% (19/95) via the i.v. catheter (nurse technique). Of stat ED blood work, 24% was for admitted patients held in the ED. Laboratory reporting times are delayed with these root causes: laboratory assistant availability; recollection rate; volume of tests for ED admitted patients; and order processing time.