In Support of Magnani and Taylor

We, the undersigned, endorse the proposal published by Barbarajean Magnani, MD, PhD, and Clive Taylor, MD, Dphil,1 in their recent Archives of Pathology & Laboratory Medicine editorial. The time has come to acknowledge that immunohistochemistry is used as an assay, not only a stain, and merits the higher level of quality assurance associated with immunoassays.2 Although the editorial does not prescribe specific new regulations, we share the view expressed in the Magnani-Taylor editorial that existing quality assurance requirements for immunoassays—learned after decades of experience—are a reasonable starting point. This statement is intended to raise awareness, stimulate discussion, and express support for much-needed improvements to clinical immunohistochemistry laboratory practice to enhance patient care. The planning of the 2026 immunohistochemistry accreditation checklist should begin now.