Capacity-Responsive COVID-19 Testing Performance in Emergency Departments: Turnaround Time Thresholds for Lateral...

Area of Science:

• Emergency Medicine
• Infectious Disease Diagnostics
• Health Systems Operations

Background:

• The COVID-19 pandemic placed significant operational stress on emergency departments (EDs).
• Mandatory testing influenced patient flow and length-of-stay (LOS).
• Two primary testing modalities, lateral flow assays (LFAs) and polymerase chain reaction (PCR), had different operational dependencies.

Purpose of the Study:

• To compare the performance of LFAs and PCR in EDs under varying operational pressures.
• To evaluate the impact of turnaround time (TAT) on the association between testing modality and ED LOS.
• To assess the stability of testing modalities during periods of high ED volume.

Main Methods:

• Retrospective observational study of 31,737 COVID-19 testing encounters (LFA and PCR).
• Propensity score matching (PSM) created 8,492 balanced LFA-PCR pairs.
• Turnaround time (TAT) was analyzed as an operational stress indicator influencing ED LOS and modality performance variability.

Main Results:

• LFA was associated with longer ED LOS (8.3 hours) compared to PCR (5.8 hours).
• The LOS difference widened significantly as TAT increased, particularly beyond 90 minutes.
• LFAs showed higher operational variability and degraded under strain, while PCR performance remained stable.

Conclusions:

• Turnaround time (TAT) is a key indicator of ED system capacity.
• LFA performance declines under operational strain, unlike more stable PCR testing.
• Adaptive testing strategies, prioritizing PCR during high TAT periods, can enhance ED resilience and patient flow.