Use of the Abbott i-STAT®1 point of care device for hCG quantification in early pregnancy

To evaluate the use of the Abbott i-STAT®1 point-of-care-test (POCT) device for measurement of human chorionic gonadotropin (hCG) to support the management of early pregnancy complications in a remote early pregnancy unit (EPU).

Women attending the EPU who required an hCG blood test were invited to take part in the study. Participants provided an additional blood sample for whole blood hCG measurement using the Abbott i-STAT®1 analyzer. The remaining sample was sent to the hospital laboratory for hCG analysis using the Abbott Architect, the designated comparator method. Statistical analysis was performed using Analyze-IT software.

A total of 61 women were recruited, including cases of pregnancy of unknown location, ectopic pregnancy, and molar pregnancy. Fourteen hCG results that were outside the i-STAT®1 assay's quantitative range, although still broadly concordant with laboratory hCG results, were excluded from statistical analysis. Analysis of the remaining 47 paired hCG results demonstrated strong agreement across the concentration range (4-2072 IU/L), with excellent Spearman correlation (r = 0.99, P < 0.001). Passing-Bablok linear regression indicated good agreement (y = 1.18 + 0.96x) and Bland-Altman analysis showed a mean difference of -23.7 IU/L (-3.5%).

All hCG results from the i-STAT®1 analyzer were clinically concordant with the central laboratory method, supporting its application in an EPU setting using established clinical decision thresholds. However, further verification through larger-scale studies is necessary before the i-STAT®1 analyzer can be integrated into clinical practice.