We are going to collect blood to analyse Oxytocin and Vasopressin levels using EDTA tubes, but the problem is that we are going to do other collections as well for several participants. So much so that we would only have all of them collected after 6 hours of the first collection. And because we are short on people and the lab we are going to process the samples is far away, we wanted to know if EDTA tubes can handle staying on ice for that long, especially accounting that we want to analyse Oxytocin and Vasopressin, which as far as I know are very sensetive.

We're also going to analyse ACTH but I've found an article stating that it can withstand 6 hours on ice or room temperature, but didn't find anything of the sorts about Oxytocin and Vasopressin.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6297593/