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

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.

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.

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.

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 analyses were performed with SPSS software version 16.0, and P ≤ 0.05 was considered statistically significant.

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%.

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.