ISO 13485 planning related query

If your reagent is not medical device, than you do not need medical device file and orocedure for advisory notice. You can state in the Quality Manual that requirements 4.2.3 Medical device file and 8.2.3 Reporting to regulatory authorities are not applicable for your quality management system. 

Risk analysis is applicable for you. You have to take a risk assesment for the whole production process of your reagent. It means from the purchasing and storage of raw material, to delivering the reagent to medical device company. 

For more information about How to use ISO 14971 to manage risks for medical devices, you can read in the following article: 

https://advisera.com/13485academy/blog/2017/09/21/how-to-use-iso-14971-to-manage-risks-for-medical-devices/