In vitro diagnostic (IVD) reagents intended for clinical use are regulated by FDA as medical devices under 21 CFR Part 809. Depending on the risk classification, they may require 510(k) clearance, premarket approval (PMA), or De Novo authorization before commercial distribution. Research-use-only (RUO) reagents are exempt from premarket review but must be labeled accordingly and cannot be promoted for clinical use.

Certified reference materials are characterized substances with precisely established property values, used to calibrate analytical instruments or validate measurement methods rather than to diagnose disease directly. They are typically accompanied by a certificate of analysis traceable to a national or international metrology standard. Diagnostic reagents, by contrast, are designed to detect or measure a specific analyte in a patient or environmental sample.