Identifying causes of laboratory turnaround time delay in the emergency department

Laboratory turnaround time (TAT) is an important determinant of patient stay and quality of care. Our objective is to evaluate laboratory TAT in our emergency department (ED) and to generate a simple model for identifying the primary causes for delay.

We measured TATs of hemoglobin, potassium, and prothrombin time tests requested in the ED of a tertiary-care, metropolitan hospital during a consecutive one-week period. The time of different steps (physician order, nurse registration, blood-draw, specimen dispatch from the ED, specimen arrival at the laboratory, and result availability) in the test turnaround process were recorded and the intervals between these steps (order processing, specimen collection, ED waiting, transit, and within-laboratory time) and total TAT were calculated. Median TATs for hemoglobin and potassium were compared with those of the 1990 Q-Probes Study (25 min for hemoglobin and 36 min for potassium) and its recommended goals (45 min for 90% of tests). Intervals were compared according to the proportion of TAT they comprised.

Median TATs (170 min for 132 hemoglobin tests, 225 min for 172 potassium tests, and 195.5 min for 128 prothrombin tests) were drastically longer than Q-Probes reported and recommended TATs. The longest intervals were ED waiting time and order processing.

Laboratory TAT varies among institutions, and data are sparse in developing countries. In our ED, actions to reduce ED waiting time and order processing are top priorities. We recommend utilization of this model by other institutions in settings with limited resources to identify their own priorities for reducing laboratory TAT.