A-337 The Utility of Urinary Human Chorionic Gonadotropin Testing in the Emergency Department

Abstract Background Human chorionic gonadotropin (hCG) levels are measured in both urine and blood as an indication of suspected pregnancy, and assessment of progress of conception. It is also measured in the investigation of patients presenting with acute abdomen and suspected of ectopic or molar pregnancy. This study reviewed the utility of urine pregnancy test in a large university teaching hospital. Methods Results of all urinary hCG tests (using hCG Combo Pregnancy kit, MEDLINE, IL) performed as point of care in the emergency department during the year 2023 were obtained. Corresponding plasma hcG levels performed (Total β-HCG Alinity immunoassay, Abbott Diagnostics, IL) were also obtained. Analysis of hCG testing outcomes were assessed. Results A total of 2848 urinary hCG tests were performed during the study period. The majority 2113 (74.2%) of samples were negative for hCG whereas 835 samples (29.3) were positive. Among the positive hCG urine samples, 401 patients (48%) had plasma hCG requested and performed. Plasma hCG values ranged from 2.4 (26.5) to 219,462.5 mIU/mL (median 16,872.35 mIU/mL). One plasma sample with corresponding positive urinary hCG result had plasma hCG level 2.4 mIU/mL which is below the detection limit of the assay suggesting a false positive urinary hCG result. Among the 13 patients with serial plasma hCG values, only one patient exhibited doubling (48 hours) hCG values when less than 13,000 mIU/mL. One patient had a declining serial hCG plasma values suggesting failing conception. The remaining patients with consecutive plasma hCG values cannot be assessed as either the time gap was excessive or hCG values were markedly elevated ( 30,000 mIU/mL). Conclusions Although the utility of urinary hCG testing in the emergency department appeared appropriate, unnecessary repeat analysis with appropriate plasma request represented 3.2%. An electronic test request duplicate notification may help resolve this unnecessary repeat.