What is Attached Testing?
"Attached testing" is not a standard medical or laboratory medicine term found in clinical practice guidelines or diagnostic testing protocols. The term does not appear in established guidelines for molecular diagnostics, companion diagnostics, laboratory testing, or biomarker assessment.
Context and Clarification
Based on the available evidence, there are several established testing concepts that might be confused with "attached testing":
1. Companion Diagnostic Testing
The most relevant concept in clinical medicine is companion diagnostics, which are FDA-regulated tests that are essential for the safe and effective use of a particular therapeutic agent 1. These tests:
- Use specific FDA-approved assays (e.g., PD-L1 testing with specific antibodies like Dako/Agilent 22c3 for pembrolizumab) 2
- Are "attached" to specific drugs in that they must be performed before prescribing certain targeted therapies
- Require premarket approval as class III devices 1
2. Reflex Testing
Another established concept is reflex supplemental testing, where additional tests are automatically performed based on initial screening results 3. For example:
- Screening-test-positive samples automatically trigger confirmatory testing
- No separate order is required—the supplemental test is "attached" to the screening protocol
3. Physical Attachment in Research Settings
In research contexts, "attached" may refer to physical probe attachment 4, but this is not a diagnostic testing terminology used in clinical laboratory medicine.
Common Pitfall
If you encountered "attached testing" in clinical documentation, clarify the intended meaning with the ordering provider, as this may be:
- A local institutional term
- A miscommunication about companion diagnostics
- Reference to reflex testing protocols
- A typographical error
The established terminology in laboratory medicine uses terms like companion diagnostics, complementary diagnostics, reflex testing, or sequential testing algorithms 1, 3.