A marker for examining a diabetic complication comprising a compound represented by the following Formula (1), or a salt thereof. A method of examining a diabetic complication with an amount of the marker as an indicator including: (A) a step of measuring the amount of the marker in a sample collected from a test subject; and (B) a step of determining presence or absence, or a risk of development of the diabetic complication based on a result of measurement of the amount of the marker comprising Formula (1), or a salt thereof: