20 CFR §30.806

OWCP requires the submission of rationalized medical evidence of sufficient probative value to convince the fact-finder that the covered Part E employee experienced a loss in wages in his or her trigger month due to a covered illness, i.e., medical evidence based on a physician's fully explained and reasoned decision (see § 30.805(a)(3)). A loss in wages in the trigger month due solely to non-covered illness matters, such as a reduction in force or voluntary retirement, is not proof of compensable wage-loss under Part E.