3)A control reaction must also be carried out with 3 drops of '''donor''' plasma and 1 drop of '''donor''' red blood cells. If agglutination occurs then there is an error and the test must be repeated. | 3)A control reaction must also be carried out with 3 drops of '''donor''' plasma and 1 drop of '''donor''' red blood cells. If agglutination occurs then there is an error and the test must be repeated. |