Point-of-Care Testing Reduces Length of Stay in Emergency Department Chest Pain Patients

Abstract

We determine the effect of cardiac troponin I point-of-care testing on emergency department (ED) length of stay in chest pain patients. This was a before-and-after trial in a university-based ED with 75,000 annual visits. Participants were consecutive patients with a chief complaint of chest pain who were admitted to the hospital. During the first 2-week period (before), only central laboratory testing of troponin was performed. During the second 2-week period (after), treating nurses performed bedside point-of-care testing for troponin I, as well as central laboratory testing. Test turnaround times, time from triage until calling in admissions, and time from triage until patients left the ED to be transferred to a floor (ED length of stay) were determined and compared between the 2 study periods. Comparisons between study periods are expressed as mean differences with 95% confidence intervals (CIs). A sample of 100 patients in each group had 90% power to detect a 1-hour difference in length of stay (2-tailed alpha=0.05). There were 232 patients before and 134 after introduction of point-of-care testing. Mean age (SD) was 63 years (16 years), and 44% were female patients. Baseline characteristics were similar in both groups. The rate of positive troponins was also similar (9.5% versus 6.1%). ED length of stay was significantly reduced after introduction of point-of-care testing (5.2 hours [95% CI 4.6 to 5.8 hours] versus 7.1 hours [95% CI 6.6 to 7.7 hours]; mean difference 1.9 hours [95% CI 1.1 to 2.7 hours]). The time until the admission was called in to bed control was also significantly reduced by introducing point-of-care testing (2.7 hours [95% CI 2.4 to 3.1 hours] versus 4.7 hours [95% CI 4.3 to 5.0 hours]; mean difference 1.9 hours [95% CI 1.4 to 2.5 hours]). Point-of-care testing turnaround (14.8 minutes [95% CI 14.1 to 15.5 minutes]) was significantly shorter than for central laboratory testing (83 minutes [95% CI 77 to 89 minutes]; mean difference 68 minutes [95% CI 62 minutes to 74 minutes]). With central testing as the criterion standard, point-of-care testing had a sensitivity of 100% (95% CI 63% to 100%) and a specificity of 96% (95% CI 92% to 99%). Bedside performance of troponin I point-of-care testing by treating nurses significantly reduces ED length of stay.