The 21-4140 form is a form that the VA uses to confirm the employment status of veterans receiving total disability based on individual unemployability (TDIU). TDIU benefits are determined by whether the veteran can maintain substantially gainful employment. That means the VA will only continue these benefits as long as the veteran’s employability status does not improve. If you receive a TDIU rating, you are required to complete the 21-4140 form annually to continue qualifying for these benefits. Veterans receiving TDIU may also be required to attend regular C&P exams.