I'm carrying out a qualitative systematic review on the barriers to screening uptake. Following my search and screening for primary studies to be included, I ended up with 5 primary studies. 3 of these studies stated that they used quantitative cross-sectional study designs, however after reading these three studies, I have realized that they provide qualitative evidence, that is, they discuss experiences and barriers to screening which is relevant to my review. Given that my review is qualitative, can I use the qualitative data from these quantitative studies, provided I state this in my selection criteria?