I would like to examine the level of TNF-alpha, IL-6, Il-1beta, Il-8 in the supernatant of human adipose tissue after various periods of storage in various preservative fluids. Is it necessary to prepare a sample before the detection? So far, I have been trying to harvest a supernatant and store it in -80 degrees after spinning it (from tissue contamination), or not. In both cases, the detection was placed at the lower threshold; everything shows that it should be much higher. I have used a Human Inflammatory Cytokine Cytometric Bead Array (CBA) - I Kit (RUO) Bioscience. What can I do to get some more distinct results?