TGFB1 and preeclampsia: The study has been done to evaluate the threshold values and reference intervals of Regulatory T cells, TGF-β1, IL-6, and hsCRP as a comprehensive panel for preeclampsia.<h4>Materials and methods</h4>In this cross-sectional study the T-regulatory cells (CD4, CD25, FOXP3) were assessed using a flow-cytometer, and TGF-β1, and IL-6 were analysed by sandwich ELISA method and hsCRP analysed by Beckman Coulter autoanalyser.<h4>Statistical analysis</h4>The reference range for the parameters in the studied groups was estimated based on CLSI C28-A3 guidelines.