Dabigatran-induced lupus temporarily preventing blood group determination.

Epistaxis resulted in severe anemia in an 89-year-old Caucasian woman under a therapy with dabigatran for 12 months because of atrial fibrillation. Correction of the anemia was difficult because it was impossible to assess her blood group due to polyagglutination. Since hospital records disclosed that in 2011, her blood group was O positive, acquired polyagglutination was assumed. After 66 days, it was again possible to assess the blood group as O positive. Immunologic investigations disclosed that antinuclear antibodies and antihistone antibodies were elevated, and antibodies to double-stranded DNA were negative. Drug-induced lupus was diagnosed due to the autoantibody profile detected.