I'm writing a systematic review on endothelial cell cultures undergoing a certain treatment. In all studies included, the cultures come from an immortalized cell line. I'm assessing bias in the studies, following the Cochrane tool for critical appraisal, and noticed that many of the protocols do not describe random allocation of treatments. Furthermore, the Cochrane tool is specifically developed for RCTs, and a few of the questions feel only loosely applicable to the specific conditions of in vitro studies. As far as I know, there's no critical appraisal tool specifically developed for in vitro studies of cells, only human or animal studies.
I'm probably getting caught in the weeds here, but I have a few questions. Would random allocation of treatment vs no treatment potentially harm validity, if all the cells come from the same cell line and are essentially identical? If we deem random allocation non-applicable to the specific context of in vitro cell culture experiments, is it kosher to modify the Cochrane tool and omit random allocation as a criterion?
Hope this makes sense. Thanks for your help.