Monofilament Tests

Monofilament tests for patients with sensory deficits or individuals who are at risk for sensory impairments and loss of protective sensation (LOPS). Evaluation for diabetic peripheral neuropathy using Semmes-Weinstein monofilaments

Key Words: Monofilament tests, diabetic peripheral neuropathy, sensory testing, tactile testing, Semmes-Weinstein monofilament, 5.07 monofilament, loss of protective sensation (LOPS), monofilament testing for LOPS of foot, diabetic foot sensory testing, diabetes mellitus  

One of the many potential medical consequences of diabetes is peripheral neuropathy (PN), a condition that causes damage to peripheral nerves leading to altered sensation (tingling, numbness, pain, or a crawling feeling) of the skin and a loss of protective sensation (LOPS). The areas of greatest risk are those at weight bearing surfaces, like the planter surface of the foot (heel, metatarsal heads, distal phalanx of the toes, lateral border) or atop the toes when a musculoskeletal deformity condition exists that causes a metatarsal phalangeal joint hyperextension with interphalangeal joint flexion (claw toe).

A loss of protective sensation and the inability to detect an injury or compromise to the skin (nick, cut, blister) increases the risk of developing an infection and ulceration of the foot, and the potential for lower extremity amputation.

Most peripheral neuropathy cases are detected and treated in a primary healthcare setting like a physician’s office or physical therapy clinic. Monofilament testing is an inexpensive, non-invasive, easy-to-use, portable, and first line-of-detection test for assessing the loss of protective sensation.

A monofilament is a single-fiber nylon strand, engineered and calibrated to buckle at a given perpendicular force of application, used for the purpose of testing for peripheral neuropathy or detecting changes in neurological status. The Semmes-Weinstein monofilaments are the standard, being the first engineered monofilaments for detecting loss of protective sensation associated with loss of large-fiber nerve function. The three most used monofilament test strands to test for peripheral neuropathy of a diabetic foot are 4.08, 5.07, and 6.10. These numbers are derived from the logarithm of the applied force in milligrams.

• 4.08 monofilament is engineered to buckle (bend into a “C” curve) at 1 gram of force applied linearly
• 5.07 monofilament is engineered to buckle (bend into a “C” curve) at 10 grams of force applied linearly. Note: The 5.07 monofilament is most commonly used in conducting a peripheral neuropathy sensory test on the foot
• 6.10 monofilament is engineered to buckle (bend into a “C” curve) at 100 grams of force applied linearly

Indication for Conducting a Monofilament Sensory Test

Monofilament testing of both feet should be conducted on patients who have:

• Tingling, numbness, burning or crawling sensation in one or both feet*
• Been diagnosed with diabetes**
• A developing diabetic ulcer

*It is important to note that the early detection of reduced loss of protective sensation can help lower the incidence of diabetic and neuropathic ulcers and the possibility of lower extremity amputation.

**The American Diabetes Association states that all individuals diagnosed with diabetes should be screened for loss of protective sensation in their feet at the time of diagnosis and at least annually thereafter. If a musculoskeletal deformity exists that provides pressure points, then screening should be conducted more frequently.

ProHealthcareProducts.com carries a wide variety of monofilament tests including disposable and reusable monofilaments from industry leaders Baseline and West.