How to dilute in Quantikine ELISA (R&D systems) - (Nov/15/2013 )

Hello!
I am trying to do a simple ELISA from kits (all quantikine ELISA kits from R&D system). I am doing the TNF (cat. noDTA00C) , Il-12 (p40) (cat. no DP400) and Il-10 (cat. no D1000B) ELISA. I have both serum and cell supernatant samples (from monocyte derived macrophages).

My problem is how to dilute the samples, in some kit there is a guideline, but not in some. For example, in the TNF kit (cat. DTA00C) they provide the reagent RD6-35, but no information on if I can dilute both supernatant and serum with it or how samples should be diluted. In the Il-12 kit, the reagents are RD5P for supernatant and RD6-13 for serum, but no information on dilution. In Il-10 this is RD5C and RD6P for supernatant and serum, respectively.
I wonder if you have any experience in this and how did you dilute your samples to stay within the standard curve?
Many many thanks for any answer! 

Where the kit does not provide relevant info, I would dilute the supernatant samples in the fresh culture medium that was used to grow the cells. For the serum samples, I would dilute in the same buffer used to prepare the standard curve.