Reducing unnecessary testing in the emergency department: The case for INR and aPTT

Routine coagulation testing is rarely indicated in the emergency department. Our goal is to determine the combined effects of uncoupling routine coagulation testing (i.e., international normalized ratio [INR]; activated partial thromboplastin time [aPTT]), disseminating an educational module, and implementing a clinical decision support system (CDSS) on coagulation testing rates in two academic emergency departments.

A prospective pre-post study of INR-aPTT uncoupling, educational module distribution, and CDSS implementation in two academic emergency departments. All patients ages 18 years and older undergoing evaluation and treatment during the period of August 1, 2015, to November 30, 2017, were included. Primary outcome was coagulation testing utilization during the emergency department encounter. Secondary outcomes included associated costs, frequency of downstream testing, and frequency of blood transfusions.

Uncoupling INR-aPTT testing combined with educational module distribution and CDSS implementation resulted in significantly decreased coupled INR-aPTT testing, with significantly increased selective INR and aPTT testing. Overall, the aggregate rate of coagulation testing declined for both INR and aPTT testing (48 tests/100 patients/day to 26 tests/100 patients/day). There was a significant decrease in associated daily costs (median cost per day: $1048.32 v. $601.68), realizing estimated annual savings of $163,023 Canadian dollars (CAD). There was no signal of increased downstream testing or patient blood product requirements.

Compared to baseline practice patterns, our multimodal initiative significantly decreased coagulation testing, with meaningful cost savings and without evidence of patient harm. Clinicians and administrators now have a growing toolkit to target the plethora of low-value tests and treatments in emergency medicine.