Possible sources of discrepancies in the use of the Semmes-Weinstein monofilament. Impact on prevalence of insensate foot and workload requirements.

Abstract

Using a combination of sites 3 and 4 for monofilament testing gives a reasonable compromise for time, sensitivity, and specificity. Minor changes in sensitivity and specificity can lead to major changes in the prevalence of neuropathy, with implications for workload.

Differences in the performance of commercially available 10-g monofilaments.

“…The use of monofilaments in practice has been supported by research that has demonstrated their capacity to identify patients at risk for ulceration (13,18,(21)(22)(23)(24)(25)(26)(27)(28). However, many researchers who have advocated the use of monofilaments have had the benefit of calibrating their monofilaments before use (22,23,28). Clinicians in practice are rarely able to access calibration equipment or procedures and have relied on the minimal data provided by manufacturers as an assurance of monofilament reliability.…”

“…McGill et al (28) highlighted the effect of misdiagnosing sensate patients as insensate in their work on monofilaments. That research showed that a minor reduction in the specificity of monofilament testing resulted in 388 patients incorrectly recruited for specialist education and intervention.…”

“…Most studies that have used monofilaments to categorize individuals according to risk status have used Semmes-Weinstein filaments (21)(22)(23)(24)(25)(26)(27)(28). Rith Najarian et al (22) detailed the results of calibration.…”

“…However, the sensitivity of monofilaments in detecting high-risk patients varies markedly depending on the research cited. The variation in monofilament sensitivity may be a direct consequence of discrepancies in the accuracy and reliability of the monofilaments (14,17,28). In practice, these discrepancies may lead to inadequate and inappropriate screening criteria used to identify patients at risk.…”

“…Extrinsic factors include the testing proce-dure adopted (e.g., the number and location of testing sites, on which little evidence and no consensus exist) (14,28). Clearly, some extrinsic factors remain difficult or impossible to measure, such as the reliability of the patient' s response.…”