Tehran University of Medical Sciences International Journal of Hematology-Oncology and Stem Cell Research 2008-2207 8 1 2014 03 15 1 4 Ahmad Gharehbaghian Hematology and Blood Banking Department, School of Allied Medical Sciences, Shahid Beheshti University of Medical Sciences; Tehran, Iran. AND Pediatric congenital Hematologic Disorders Research Center, Tehran, Iran. Behrooz Ghezelbash Iranian blood Transfusion Organization Research Center, Tehran, Iran. Sima Aghazade Ardebile University of Medical Sciences, Ardebile, Iran. Mohammad Taher Hojjati Mazandaran University of Medical Sciences, Mazandaran, Iran. 2015 10 14 Introduction: Alloimmunization is a reaction of the immune system to foreign antigens. For prevention of alloantibody formation, performing of type and screen test is necessary on a patient's blood specimen as part of pre-transfusion testing. Materials and method: In this cross-sectional study, type and screen test done for 1420 patients with elective surgery for detection of alloantibody in Imam Khomeini hospital in Ardabil. Results: Prevalence of alloantibody in this population was 0.92% (13 patients) and 99.2% (1407 patients) showed no alloantibody in their serum. The most prevalent alloantibody was anti-K, anti-E and anti-c. No significant relationship observed between sex and alloimmunization rate. Conclusion: Performance of type and screen test play an important role in reducing the rate of alloimmunization, and also, could reduce the demands for blood reservation in hospital blood banks. https://ijhoscr.tums.ac.ir/index.php/ijhoscr/article/view/435 https://ijhoscr.tums.ac.ir/index.php/ijhoscr/article/download/435/362