Professional
Formal
IVT
companion diagnostic
A medical device used to identify patients who are most likely to benefit from a particular therapeutic product.
Full Definition
A companion diagnostic is an in vitro diagnostic device that provides information essential for the safe and effective use of a corresponding therapeutic product. These tests identify patient subpopulations most likely to respond to specific treatments or those at increased risk for serious adverse reactions. Regulatory approval typically occurs simultaneously with the associated therapeutic agent, creating a co-dependent relationship between diagnosis and treatment.
Usage
Usage note: Hyphenate when used as compound modifier. Distinguish from complementary diagnostics.
In Context
- "FDA approval of the companion diagnostic was required before the targeted therapy could be prescribed." — Regulatory submission
- "The companion diagnostic identified 23% of patients as eligible for the investigational treatment." — Clinical trial report
Also known as
CDx
paired diagnostic
Contrasted with
complementary diagnostic
standalone test
Don't confuse with
complementary diagnostic
biomarker assay