====== Functional Assay ======

A **functional assay** is a laboratory test designed to evaluate whether a biological component (such as a gene, protein, or cell) performs its expected **biological function** under defined experimental conditions.

===== Definition =====
A functional assay is used to assess the **activity, behavior, or performance** of a biological molecule or system, often to determine its role in health or disease.

> It measures what the component **does**, not just what it **is**.

===== Common Applications =====
  * Determining the effect of **genetic variants** (e.g. VUS)
  * Testing **enzyme activity**
  * Evaluating **drug responses** in vitro
  * Measuring **cell proliferation**, apoptosis, or migration
  * Assessing **receptor signaling** capacity

===== Examples =====
^ Target ^ What It Tests ^ Example ^
| Enzyme       | Catalytic activity                | ATPase assay for energy metabolism |
| Receptor     | Signal transduction               | G-protein coupled receptor activation |
| Gene variant | Transcriptional regulation        | Luciferase reporter assay |
| Cell         | Proliferation/apoptosis/migration | MTT assay, scratch wound healing test |

===== Importance =====
Functional assays are essential in:
  * Interpreting the clinical relevance of **mutations**
  * Validating **therapeutic targets**
  * Exploring **mechanisms of disease**
  * Confirming **biological activity** of recombinant or engineered molecules

===== Related Terms =====
  * [[biological assay]]
  * [[luciferase reporter assay]]
  * [[in vitro assay]]
  * [[variant of uncertain significance]]