The Leptin BioAssay(TM) ELISA Kit utilizes the sandwich immunoassay technique for the detection and quantification of endogenous levels of natural and/or recombinant human Leptin proteins within the range of 63-4000pg/ml. Assay Time: 4.5 hours Detection Method: Colorimetric 450 nm Storage and Stability: Store powder at 4C liquid at -20C. Store other components at 4C. Stable for 6 months after receipt. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap.