Seorang wanita, 24 tahun, masuk rumah sakit dengan keluhan utama lemah sejak 1 minggu. Pasien didiagnosis diduga chronic myeloid leukemia (CML) sejak 4 bulan. Pada pemeriksaan fisis ditemukan kesan anemis, splenomegali masif dan hepatomegali. Pemeriksaan laboratorium mendapatkan hemoglobin 6,6 g/dl, eritrosit 1.480.000/mm3, leukosit 629.080/mm3, trombosit 149.000/mm3. Golongan darah A (positif-2 /weak antigen), rhesus negatif dan incompatibility minor mixed field. Pada CML terjadi injury DNA yaitu translokasi pada kromosom 9 dan 22. Translokasi pada kromosom 9 diduga menyebabkan weak/missing antigen pada eritrosit, terkait incompatibility minor mixed field. Pada kasus ini darah dapat ditransfusikan karena incompatible minor mixed field samadengan auto control indirect antihuman globulin test. Perlu informasi diagnosis dan riwayat penyakit sebelumnya pada pemeriksaan pretransfusi.A 24-year-old woman was hospitalized with chief complaint general weakness since the previous week. She had been suspected with Chronic Myeloid Leukemia (CML) since 4 months ago. The patient was anemic, with massive spleen and liver enlargement. Laboratory examination found haemoglobin 6.6 g/dL, RBC 1.480.000/mm3, leukosit 629.098/mm3, trombosit 149.000/mm3. Blood group A (positive-2, weak antigen), rhesus negative, and mixed field minor incompatibility. In CML, there is DNA injury which is translocation of chromosomes 9 and 22. Translocation of chromosome 9 is correlated with weak/missing antigen on the erythrocytes related to mixed field minor incompatibility. In this case, the blood could be transfused because the minor incompatibility was equal with the autocontrol indirect antihuman globulin test. Information of previous medical history is necessary in the pretransfusion examination.Â