Written and maintained by CASRAI Editorial Board
Last updated
This page describes products and general use; it is not medical advice.
A Semmes-Weinstein monofilament is a thin nylon filament, usually mounted on a handle, that bends at a fixed amount of force. The 5.07 filament is labelled 10 g. Clinic staff, buyers and students know it as the standard 10 g monofilament.
What it is
The device is a nylon filament mounted on a holder and standardized to deliver a defined force when applied. An academic diabetic foot program describes its device as “a nylon filament mounted on a holder that has been standardized to deliver a 10 gram force when properly applied” (LSU Health Sciences Center Diabetes Foot Program, Filament Application Instructions, rev. 9/99).
Who handles it: clinic staff who stock and maintain the supplies. For the wider supply context see the diabetes clinic supply checklist and the podiatry office supply checklist.
How it is built
Each filament is a nylon strand of fixed length and diameter. It does not press harder as the user pushes: once the peak force for that filament is reached, the filament bends. A manufacturer catalog states that “each monofilament represents a unique amount of force” and that the filament bends when its peak force threshold is reached. Filaments are sold on holders, in fitted cases that protect them, and in folding, retracting and disposable formats.
Sizes: what 5.07 means
Filaments are labelled with a size number, not with grams. The numbers form a 20-step series. A manufacturer catalog (Fabrication Enterprises, evaluation section, 2014-2015 catalog) lists the grams of force for each size:
| Size | Force (g) | Size | Force (g) |
|---|---|---|---|
| 1.65 | 0.008 | 4.74 | 6.0 |
| 2.36 | 0.02 | 4.93 | 8.0 |
| 2.44 | 0.04 | 5.07 | 10.0 |
| 2.83 | 0.07 | 5.18 | 15.0 |
| 3.22 | 0.16 | 5.46 | 26.0 |
| 3.61 | 0.4 | 5.88 | 60.0 |
| 3.84 | 0.6 | 6.10 | 100.0 |
| 4.08 | 1.0 | 6.45 | 180.0 |
| 4.17 | 1.4 | 6.65 | 300.0 |
| 4.31 | 2.0 | ||
| 4.56 | 4.0 |
Source: Fabrication Enterprises 2014-2015 catalog, checked 2026-10-30. Forces are nominal values as listed by the manufacturer; see the accuracy section below.
Sets and formats
| Format | Contents or feature |
|---|---|
| Foot set of 6 | 2.83, 3.61, 4.31, 4.56, 5.07, 6.65 |
| Hand set of 5 | 2.83, 3.61, 4.31, 4.56, 6.65 |
| Protective 2-piece set | 4.56 and 5.07 |
| Complete set | All 20 sizes |
| Single 10 g filament | One 5.07 filament; the single comes with an instruction card sleeve, while bulk packs of 20 or 40 do not |
| Disposable 5.07 / 10 g | Listed by the manufacturer for use with LEAP or ADA protocols |
Source: Fabrication Enterprises 2014-2015 catalog, checked 2026-10-30.
Accuracy and service life
This is where the labelled value and real behavior can differ. Lavery et al. (Diabetes Res Clin Pract 2012;97(3):399-404, PMID 22560793) tested five monofilaments from each of six brands on a digital pressure plate, loading them 25 times a day for 5 days, then 200 cycles a day for 15 days. They reported that the filaments were “neither precise nor accurate”. Most did not start at 10 g, with variation of up to 30%. Repeated loading lowered the bending force, which leveled off 1-2 g below the starting value. The best filaments, starting at 10 plus or minus 1 g, stayed within 9-11 g for 7-9 days, which the authors note is enough to evaluate 70-90 patients. They concluded there is significant variation within and between manufacturers and a short useful life.
The practical reading, which is editorial interpretation: a filament label is a nominal value, and heavily used filaments may drift, so buyers have reason to check the manufacturer instructions on replacement.
Handling and care
Follow the manufacturer instructions for use, storage, cleaning and replacement of your specific product; this page does not give a clinical procedure. Fitted cases are sold to protect the filaments.
Common mistakes
- Treating the printed 10 g as exact. The Lavery study found starting forces that varied by up to 30%.
- Overlooking wear: in the Lavery study, repeated loading lowered the bending force by 1-2 g.
- Confusing the size number (5.07) with grams of force (10 g).
- Confusing this human sensory device with the von Frey method used in animal pain research; see von Frey testing for mechanical allodynia.
Related supplies
Clinics often stock other bedside sensory tools, such as the tuning fork. Monofilaments and similar tools are found among diagnostic, monitoring and imaging supplies.
FAQ
What is a Semmes-Weinstein monofilament?
A nylon filament on a handle that bends at a set force. The 5.07 size delivers a nominal 10 g.
What does 5.07 mean?
It is the filament size number; the manufacturer table lists 5.07 as 10.0 g of force.
Are monofilaments exactly 10 g?
Not necessarily. A 2012 study of six brands found most did not start at 10 g and varied by up to 30%.
How long does a filament last?
In that study the best filaments stayed within 9-11 g for 7-9 days of heavy loading. Check your manufacturer guidance.
Sources
- Fabrication Enterprises, 2014-2015 catalog, evaluation section: https://tigermedical.com/cdn/shop/files/FEI12-1391–20190213094700027.pdf (checked 2026-10-30).
- LSU Health Sciences Center Diabetes Foot Program, Filament Application Instructions, rev. 9/99: https://www.medschool.lsuhsc.edu/dfp/Filament.PDF (checked 2026-10-30).
- Lavery LA et al. Accuracy and durability of Semmes-Weinstein monofilaments: what is the useful service life? Diabetes Res Clin Pract 2012;97(3):399-404. doi:10.1016/j.diabres.2012.04.006: https://pubmed.ncbi.nlm.nih.gov/22560793/ (checked 2026-10-30).
