I use the ETF128 to assess vibratory sensation, pinprick for small fiber sensation and the 5.07 Semmes-Weinstein monofilament for loss of protective sensation. Abnormal readings on any of these tests indicates increased risk of ulceration.
It is decisive for the success of an effective secondary preventive strategy for preservation of the lower extremity to use a bottom-up risk score which starts with the definition of low risk (definded by absence of peripheral neuropathy and absence of signs for angiopathy) and to implement periodic controls (patient self-controls, controls by involved health care providers, namely GP, nurse practitionner, podiatrist) with narrowing intervals according to emerging risks.
The most comprehensive scoring system is the one elaborated by the IWGDF International Working Group on the Diabetic Foot : https://iwgdfguidelines.org/guidelines/guidelines/
It offers differentiated guidelines with separate scores for prevention (risk categories) and for stage of ulceration and is regularly revised.
A slightly less complex scoring system without numeric risk classsification, suggested by the American Diabetes Association ADA has been discussed by Boulton A in:
Article Diagnosis and Management of Diabetic Foot Complications
For German language readers I can recommend the detailed guidelines based on IWGDF risk scores, and formulated in 2013 by a Swiss working group. It has served as basis for the implementation of comprehensive and vertically integrated services in Switzerland and is widely accepted by health care providers in the country. See below.