Placental growth factor, soluble fms-like tyrosine kinase 1 and progesterone as diagnostic biomarkers for ectopic pregnancy and missed abortion

Objective: The aim of this study is to investigate if progesterone, placental growth factor (PlGF) and soluble fms-like tyrosine kinase-1 (sFlt1) serum levels are useful markers to differentiate between ectopic pregnancy (EP), missed abortion (MA) and viable intrauterine implantation pregnancy (IUP). Methods: We designed a retrospective case-control study which included 100 pregnant women (50 EP and 50 MA) at 6-8 weeks of gestation with beta hCG serum levels between 800 and 3500 UI/L and a viable IUP group. Progesterone, PIGF and sFlt-1 levels were measured with an electrochemiluminescence assay (Roche Diagnostics, Manheim, Alemania). A non parametric test was used to compare the markers in the different groups and we used receiver operating characteristic (ROC) curve analysis to calculate the area under the curve (AUC). Results: When we compared the EP group with the MA group, we didn't find significant differences for PlGF (15.1[13.2-17.4]/16.7[12.8-18.7] pg/mL) (p = 0.275). We only obtained significant differences for progesterone (9.1[3.1-16.8]/2.6[1.3-6.1] ng/mL) (p <0.001) and sFlt-1 (84[65-96]/126[94-256] pg/mL) (p <0.001). The AUC for progesterone was 0.756 and the cutoff point with better sensitivity and lower false positive rate was 6 ng/mL (sensitivity = 60%, specificity = 72.7%). The AUC for sFlt-1 was 0.842 and the cutoff point was 93 pg/mL (sensitivity = 84.5%, specificity = 86.3%). The combination of both markers allowed us to increase the AUC to 0.910. Conclusions: In conclusion, the present study suggests that sFlt-1 could be a useful marker to differentiate between an EP or a MA when beta hCG levels are similar in both groups. The combination of sFlt-1 with progesterone helps to increase the diagnostic performance. (C) 2014 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.