The move from research-grade to GMP-grade reagents is where inconsistent sourcing, performance variability, and last-minute substitutions turn into failed tech transfers and regulatory delays. This white paper breaks down the RUO, RUO+, GMP, and cGMP manufacturing grades, sets ISO 9001 against ISO 13485, and explains where 21 CFR 210-211 and 820 apply and why reagents consumed as ancillary materials generally fall outside them. It covers why starting in a facility operating an ISO 13485 certified QMS avoids requalifying a partner later, and closes with a stage-by-stage table of reagent considerations across process development, scale-up, and tech transfer.