A method that works beautifully in the sending lab can fall apart in the receiving lab for reasons nobody saw coming. A different column batch, a slightly warmer room, an operator who never learned the method’s hidden quirks, any of these can break it. In pharmaceutical quality control those surprises are not acceptable. Regulators expect the two sites to produce data that is genuinely comparable, and they expect the paper trail to prove it. Analytical method transfer is the documented, technical handover of a tested and proven analytical method from a sending laboratory, the transferor, to a receiving laboratory, the transferee. The goal is narrow but non-negotiable: prove that the…