The PlGF assay is used in combination with the sFlt‐1 assay to determine the sFlt‐1/PlGF ratio. The sFlt‐1/PlGF ratio is intended for use as an aid in the diagnosis of preeclampsia in conjunction with other diagnostic and clinical information. In addition the sFlt‐1/PlGF ratio is intended for use as an aid in short-term prediction of preeclampsia (rule-out and rule-in) in pregnant women with suspicion of preeclampsia in conjunction with other diagnostic and clinical information.
Preeclampsia (PE) is a serious complication of pregnancy characterized by hypertension and proteinuria after 20 weeks of gestation. Preeclampsia occurs in 3‐5 % of pregnancies and results in substantial maternal and fetal or neonatal mortality and morbidity. Clinical manifestations can vary from mild to severe forms; preeclampsia is still one of the leading causes of fetal and maternal morbidity and mortality.
Preeclampsia appears to be due to the release of angiogenic factors from the placenta that induce endothelial dysfunction. Serum levels of PlGF (placental growth factor) and sFlt‐1 (soluble fms‐like tyrosine kinase‐1, also known as VEGF receptor‐1) are altered in women with preeclampsia. Moreover, circulating levels of PlGF and sFlt‐1 can discriminate normal pregnancy from preeclampsia even before clinical symptoms occur. In normal pregnancy, the pro‐angiogenic factor PlGF increases during the first two trimesters and decreases as pregnancy progresses to term. In contrast, levels of the anti-angiogenic factor sFlt‐1 remain stable during the early and middle stages of gestation and increase steadily until term. In women who develop preeclampsia, sFlt‐1 levels have been found to be higher and PlGF levels have been found to be lower than in normal pregnancy.
The ratio of sFlt‐1 to PlGF has been shown to be a better predictor of preeclampsia than either measure alone. The sFlt‐1/PlGF ratio seems a reliable tool for discriminating between different types of pregnancy-related hypertensive disorders. In addition, sFlt‐1/PlGF has potential relevance as a prognostic parameter in PE and may be useful in prediction of preeclampsia and related adverse outcomes, risk stratification and management.
In the first trimester of pregnancy, a screening using PAPP‐A and PlGF is proposed for the risk of early onset preeclampsia.
In summary, PlGF and sFlt‐1 concentrations measured by immunoassay in maternal blood improve the diagnostic possibilities in preeclampsia which comprise clinical symptoms, proteinuria and uterine artery Doppler velocimetry.
PlGF in cardiovascular diseases: PlGF can be detected in normal non‐pregnant subjects at lower levels. Increased levels of PlGF can be found in patients with cardiovascular diseases as an indicator of micro- and macrovascular atherosclerosis and as a sign of pathological angiogenesis. In addition PlGF has been shown to be an independent predictor of cardiovascular morbidity and mortality in patients with type 1 und type 2 diabetes.