Measurement notes
Record the raw force or response sequence before threshold calculation. Keep the same paw order, contact site, ramp behavior, and response rule across groups.
Endpoint methods library
Pain and nociception endpoint
Mechanical withdrawal threshold
A force-based endpoint used in von Frey testing to quantify the stimulus intensity associated with a defined paw withdrawal response.
Unit
grams force or millinewtons
Readout
Mechanical force at withdrawal response
Assays
von Frey and mechanical sensitivity testing
Decision summary
Use this endpoint when the experiment needs a repeatable readout of mechanical sensitivity or allodynia. Interpret the threshold alongside motor status, tissue condition, and protocol controls so the result is anchored to the assay context. The endpoint is strongest when the response definition, trial spacing, application site, and analysis method are fixed before data collection.
| Primary value | Mechanical force at withdrawal response |
|---|---|
| Common units | grams force or millinewtons, depending on device output |
| Response event | Paw withdrawal, flinch, licking, guarding, or other pre-defined nocifensive response |
| Typical structure | Repeated trials per paw with acclimation and spacing between applications |
| Do not infer alone | Pain affect, spontaneous pain, motor deficit, or disease mechanism |
Interpretation limit
A lower threshold can indicate mechanical hypersensitivity, but interpretation depends on controls, motor status, tissue condition, and protocol consistency.
Data capture
Store animal ID, paw, trial number, force, response, excluded trial flag, operator, date, and notes so the threshold can be audited later.
Confound checks
- Insufficient acclimation to mesh floor, chamber, or handler.
- Stimulus probe applied at a changing angle or contact point.
- Motor impairment, sedation, stress freezing, or escape behavior that changes response expression.
- Inflammation, wound, or paw condition unrelated to the experimental question.
- Unblinded scoring or changing response criteria during the session.
Reporting checklist
- Device type and output unit.
- Species, strain, sex, age or weight range, and group structure.
- Acclimation duration, chamber type, mesh surface, and room conditions.
- Application site, force ramp or filament sequence, and cutoff rules.
- Positive response definition and number of trials per paw.
- Exclusion criteria, blinding, randomization, and analysis method.
Related workflow paths
Pair the endpoint definition with protocol controls, threshold calculation, and the apparatus path used to generate the raw response data.
Electric Von Frey protocol
Runnable protocol with setup, response criteria, exclusions, and reporting language.
Von Frey threshold calculator
Interactive support for up-down threshold calculations and response series review.
Electric Von Frey apparatus
Product path for electronic mechanical sensitivity testing.
