The Blood donation save lives and improves human health. The leak of blood donors has been a problem for the Blood Banks of the countries in the world. The principal preoccupation in the Blood Banks is the blood safety, because of that one of the most important steps now of the blood donor eligibility is the selection process.

Evaluated the deferral causas of the donors served in the donation center of de banco municipal de sangre del distrito capital from august 2023 to august 2024. determined the deferred rate of the donors served in de donation service in banco municipal de sangre del distrito capital. characterized the deferral causes by age in the donors served in the donation center in banco municipal de sangre del distrito capital characterized the deferral causes by sex in the donor served in the donation center in banco municipal de sangre del distrito capital.

The study will be quantitative, descriptive, correlational, documental, transverse and retrospective, of donors served in the donation service of the Banco Municipal de Sangre Del Distrito Capital from august 2023 to august 2024. To this study the universe for the sample was all the donors served in the donation service in banco municipal de sangre del distrito capital from august 2023 to august 2024. From this universe the sample was taken by the deferral donors during the interview of the donors.

From the 10,258 donors, 2,219 were deferred corresponding to a rate of 21.63%. The three principal causes of deferred were low hematocrit, arterial hypertension and drug use. The highest number of deferred cases were found among the group of 25 to 34 years (25%), being hypertension (20.4%), low hematocrit (18.58%) and not good sleeping (14.47%) the principles causes. The male sex were predominated in the deferral (59%), being the hypertension (21.09%), the low hematocrit (20.55%) and not good sleeping (11.81%) the principles causes, and in the female sex were the low hematocrit (20.33%), hypertension (19.34%) and drug use (14.42%).

it's exist a very high heterogeneity of the deferral causes in the donors services, with a high influence of the medical doctors and hemoterapist that work in the donors centers, who are in charged of the donor interview and decided the deferral of the donors. we recommended the periodic evaluation of the donor questionnaire, and the approval of the new Law of the blood bank where the standards of de deferral causes are standardized and adapted to international protocols.