Comparison of Result Times Between Urine and Whole Blood Point-of-care Pregnancy Testing

Point-of-care (POC) pregnancy testing is commonly performed in the emergency department (ED). One prior study demonstrated equivalent accuracy between urine and whole blood for one common brand of POC pregnancy testing. Our study sought to determine the difference in result times when comparing whole blood versus urine for the same brand of POC pregnancy testing.

We conducted a prospective, observational study at an urban, academic, tertiary care hospital comparing the turnaround time between order and result for urine and whole blood pregnancy tests collected according to standard protocol without intervention from the investigators. After the blood was collected, the nurse would place three drops onto a Beckman Coulter ICON 25 Rapid HCG bedside pregnancy test and set a timer for 10 minutes. At the end of the 10 minutes, the result and time were recorded on an encoded data sheet and not used clinically. The same make and model analyzer was also used for urine tests in the lab located within the ED. The primary outcome was the difference in mean turnaround time between whole blood in the ED and urine testing in the adjacent lab results. Concordance between samples was assessed as a secondary outcome.

265 total patients were included in the study. The use of whole blood resulted in a mean time savings of 21 minutes (95% CI 16-25 minutes) when compared with urine (p<0.001). There was 99.6% concordance between results, with one false negative urine specimen with a quantitative HCG level of 81 mIU/L.

Our results suggest that the use of whole blood in place of urine for bedside pregnancy testing may reduce the total result turnaround time without significant changes in accuracy in this single-center study.