Our lab hasn't worked on Human placental protein samples (tissue homogenates) using the Human Granulysin PicoKine Quick ELISA Kit (FEK1280). Endogenous biotin in tissue homogenates might introduce false positive signals. We recommend the customer to run a pilot test as described below to confirm the effect of endogenous biotin first. Add tissue homogenates into the wells and then add ABC and TMB without adding any biotinylated detection antibody to see if any signal will be observed. If no signal is produced, proceed and work on the tissue sample by using the kit.