I am interested in analyzing melatonin from human saliva using ELISA kit. There are quite some manufacturers (IBL-international, Amco, salimetrics etc.) that produce such kits but I already heard some negative feedbacks, like a lack of fluctuation in salivary melatonin from ELISA comparing with radioimmunoassay. It would be very interesting to know if anyone has tried any and could give a feedback on which you found useful? Thank you!