The Leptin BioAssay(TM) ELISA Kit utilizes the luminescent sandwich assay technique for the detection and quantification of endogenous levels of natural and/or recombinant Human Leptin proteins within the range of 15-1000 pg/ml Assay Time: 4.5 hours 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.