Accuracy and speed of urine pregnancy tests done in the emergency department: a prospective study

Abstract

Our primary objective was to assess the agreement between urine pregnancy tests done in the emergency department (ED) and those done by the Calgary Laboratory Services (CLS). Our secondary objective was to compare turnaround times for tests done in the ED and those done in the laboratory. This prospective study enrolled a convenience sample of ED patients who required a pregnancy test at 1 of 3 urban Calgary EDs. Using the same urine sample from each patient, testing was done in both the ED and by the CLS using the Abbott TestPak Plus (Abbott Laboratories, Mississauga, Ont.) urine pregnancy kit. The ED data included time of urine collection, beta-hCG (human chorionic gonadotropin) result, urine specific gravity, and the time the ED nurse reported the result. The CLS data included the time sample was sent to the laboratory, time of laboratory reporting, time ED nurse was aware of the result, the urine beta-hCG result and urine specific gravity. When the ED result and CLS result differed, a serum beta-hCG assay was performed and used as the diagnostic "gold standard." There was a high level of agreement between the CLS and the ED, as indicated by a kappa value of 0.97 (95% confidence interval [CI], 0.95-0.98). The ED was significantly faster in time to initial report and time to availability on the chart, with mean differences of 25 minutes (95% CI, 22-27) and 60 minutes (95% CI, 56-64), respectively. ED nurses can perform urine pregnancy tests as accurately as laboratory technicians, and can provide results on which to base care much faster than the laboratory can. Point-of-care urine pregnancy testing may expedite the ED management of patients who require pregnancy tests.