Retrospective Cohort Analysis of the Relationship Between Emergency Department Length of Stay and Timing of First Laboratory Orders.

Background The efficiency of patient management in the Emergency Department (ED) is critical for optimizing healthcare delivery. Provider in triage (PIT) and similar ED flow models attempt to expedite throughput by decreasing the amount of time between patient arrival and initial order placement. The exact relationship between ED length of stay (LOS) and the timing of the first laboratory order, however, is unclear. The varying speed at which clinicians of different ages place laboratory orders and move patients through an ED also is understudied.  Methods A retrospective analysis was conducted using SQL from the Clarity data archive to pull all patient encounters in 2023. Linear regression models using Analysis ToolPak in Microsoft Excel were used to create and examine the relationship between LOS and the timing of the first laboratory order. Secondary outcomes using the same models were created to analyze the impact of clinician age on LOS and the relationship between clinician age and the timing of first laboratory orders.  Results Two hundred sixty-nine thousand eight hundred and eight ED visits were reviewed across three academic and 17 community emergency departments. We report a weak but statistically significant positive relationship between the timing of the first laboratory order and LOS (R² = 0.0378, p < 0.001). Secondary outcomes indicated a very weak negative correlation between clinician age and LOS (R² ≈ 0, p < 0.001) and no significant relationship between clinician age and the timing of the first laboratory order (R² ≈ 0, p > 0.05). Conclusion The timing of the first laboratory order is a significant, albeit weak, predictor of LOS in the ED. Clinician age has minimal impact on LOS and does not significantly influence the timing of the first laboratory order.