Conducting the tests coombs or antiglobulinicas calls are tests applied in the routine services of Blood Banks and Transfusion Services, as it is in the service of Transfusion Medicine General Teaching Hospital in the city of Riobamba, this test is intended to assess the presence of agglutinins in the purpose of blood transfusion or its derivatives as well as the study of blood group incompatibilities matero fetal and as support for the study of transfusion reactions resulting from the use and administration of blood products. Of the objectives is the preparation of reactive cells using monkey antisera and polyclonal to apply in validating tests coombs by his power intensity reaction as correlate their control results coombs employment screening cards . As a result of the hypothesis was obtained if was possible to validate tests negative direct and indirect Coombs using cells prepared control polyclonal and monoclonal antisera, for support of the use of these cells to negative test Coombs tests conducted anti IgG and C3d, their results were negative and correlating the results and employment Coombs control cells when these gave positive. Of the conclusions we cite that employ the combination of antisera anti-D monoclonal and polyclonal to prepare cells Coombs Control guarantee this control means as the antigenic structure RhD presents variations in epitopes that can most generate the production of non-specific antibodies or irregular representing the cause of positivity in Coombs tests, it is recommended to validate these cells with specific tests, IgG and C3d, this generates in the work an additional Coombs test negative control.La realización de las pruebas de coombs o llamadas antiglobulínicas, son pruebas que se aplican en la rutina de bancos de sangre o servicios transfusionales, como lo es en el servicio de Medicina Transfusional del Hospital General Docente de la ciudad de Riobamba, esta prueba esta destina a valorar la presencia de aglutininas en el propósito de transfusiones de sangre o sus derivados como también el estudio de incompatibilidades de grupos sanguíneos materno fetales y como apoyo en el estudio de reacciones transfusionales a consecuencia del uso y administración de hemoderivados. Esta investigación tiene como objetivo la preparación de células reactivas mediante el empleo de antisueros mono y policlonales para aplicarlos en la validación de ensayos de coombs mediante su poder de intensidad de reacción como también correlacionar este resultado con el empleo de tarjetas screeningUNACH, Sede Ecuador.