[Molecular biology in a blood bank].

Medicine has had a vertiginous advance in the last two centuries. After the first successful transfusions, transfusional medicine and blood banks arose. The ladder perform vital functions, from donor screening to the studies for the analysis of blood that are carried out before its use for transfusion and the follow-up of patients who receive blood components. Molecular biology is highly relevant in these activities, since it has allowed the reduction of window periods for the detection of diseases transmissible by blood; it has allowed the complete study of the typing of blood groups and HLA molecules, and it has allowed the adequate phenotypic interpretation of patients and donors by being able to have their genotype. The most relevant impact of the implementation of molecular biology techniques was the screening for the detection of transfusion-transmissible diseases in blood donors, which has allowed improving the safety of the components obtained. Molecular biology techniques applied in the study of the donor-recipient have allowed better care of patients who have required a transfusion or transplant. In this work, it is reviewed the importance of molecular biology in blood banks, with which the care for the Instituto Mexicano del Seguro Social beneficiaries has improved, as well as for the blood donors who are mostly not insured.