Serum soluble FMS-like tyrosine kinase-1 in ectopic pregnancy

CONTEXT: The diagnosis of an ectopic pregnancy (EP) requires the usage of serial beta-human chorionic gonadotropin (hCG) measurements and ultrasonography to locate the gestational sac. With the rising trends in its incidence, a rapid, noninvasive biomarker to detect this condition at the earliest can aid in decreasing the morbidity and mortality linked with EP. AIMS: This study was performed to determine the serum level of soluble FMS-like tyrosine kinase-1 (sFLT-1) at 4–10-week gestation in EP and normal pregnancy and to identify whether it can be used as a biomarker to distinguish an EP from a normal intrauterine pregnancy. SETTINGS AND DESIGN: This was a prospective case–control study conducted over 2 years from 2015 to 2017 in 280 women between the age groups of 19 and 38 years at a tertiary level hospital. SUBJECTS AND METHODS: Levels of sFLT-1 in sera of 140 women with EP and 140 women with normal pregnancy were assayed by a sandwich enzyme-linked immunosorbent assay at Sri Ramachandra Medical College and Research Institute, Chennai, Tamil Nadu, India. STATISTICAL ANALYSIS USED: Statistical analyses were performed with SPSS software version 16.0, and P ≤ 0.05 was considered statistically significant. RESULTS: The median sFLT-1 level in EP was 419 pg/ml. This was significantly lower than the value of 898 pg/ml in normal pregnancy. Receiver operating characteristic curve analysis showed that at a cutoff of 623 pg/ml, sFLT-1 was able to distinguish an EP from a normal intrauterine pregnancy with a sensitivity of 98.6% and a specificity of 90.7%. CONCLUSIONS: The present study showed the significant early lowering of sFLT-1 in EP and may be considered as an effective biomarker compared to beta-hCG.