Overuse of Laboratory Testing in Symptomatic First Trimester Pregnant Patients in the Emergency Department

Abstract

Emergency physicians often evaluate first trimester pregnant patients with abdominal pain and/or vaginal bleeding, with the primary goal of confirming intrauterine pregnancy (IUP). Fortunately, in patients who are not at increased risk for heterotopic pregnancy, the visualization of an IUP essentially excludes the diagnosis of ectopic pregnancy. While the initial evaluation of these patients has historically included a quantitative serum human chorionic gonadotropin (quant-hCG), ABO-Rh testing in patients with vaginal bleeding, and pelvic ultrasonography, there is little doubt that these tests are often unnecessary. The quant-hCG has no utility in ED patients with ultrasound-proven IUP and, similarly, repeating Rh testing in patients with previously documented ABO-Rh results is inappropriate. Selective testing strategies for both tests might substantially save both cost and time; however, there are only limited data on the baseline frequencies of quant-hCG and Rh testing in our patient population.The objective of this study was to determine the frequency of quant-hCG testing in emergency department (ED) patients diagnosed with an intrauterine pregnancy (IUP) during their ED visit. As a secondary aim, we analyzed the frequency of Rh testing in patients in whom a previously documented Rh was available in our electronic medical record (EMR). This was an eight-year retrospective review of all ED patients who received a pelvic ultrasound study in the department of radiology. Analysis of the ultrasound reports using natural language processing identified patients diagnosed with IUP. Laboratory results were reviewed for all patients, and investigators determined if quant-hCG and/or ABO-Rh testing was performed during the same visit as the ultrasound examination as well as whether prior Rh test results were available in the EMR at the time of the visit. From 1/1/05-12/31/12 there were 14,348 pelvic ultrasound examinations ordered in our ED. Of these, 4,510 (31%) had results that documented an IUP (76% with a documented FHR and 24% with only an intrauterine yolk sac). In these patients with IUPs, quant-hCG was ordered in 3,840 (85%). Additionally, Rh testing was performed in 2,778 patients, 906 (33%) of whom had prior Rh results available in the EMR. These results suggest that both serum quantitative hCG testing and Rh testing are overused in first trimester pregnant women in our ED. These tests appear to represent a considerable opportunity for cost and time savings through the use of selective testing strategies, and a prospective evaluation is currently underway at our institution.