Diabetics who are well controlled on insulin or oral medications are eligible to donate blood. However, people who have had diabetes since 1980 and have used bovine (beef) insulin made from cattle from the United Kingdom are not eligible to donate. This requirement is related to concerns about variant CJD, or “mad cow disease.”
Guidelines on eligibility to give blood change from time to time. The most up-to-date eligibility information can be obtained by contacting the American Red Cross blood center nearest you.