There's really nothing much to worry about--Jigs and Beaners do NOT donate blood or do any such thing that White people do to freely support and contribute to the betterment of our Society. According to The Central Blood Bank:
"Less than 1 percent of blood donations are from African Americans or Hispanics.
Though compatibility is not based on race, genetically similar blood is best for patients who need repeated or large volumes of blood transfusions, or those who have produced red blood cell antibodies for various diseases and conditions like sickle cell, heart disease and kidney disease.
Blood that closely matches a patient’s ethnicity is less likely to be rejected by the patient and provides fewer risks for complications. For example, some African American donors have different combinations of antigens in their blood like U-negative or Duff y-negative. Because these antigens are rarely found in other ethnic groups, these patients often depend on African American blood donations."
http://www.centralbloodbank.org/donate- ... d-donation
Sounds like the Blood Banks take ethnicity into account and try to find an appropriate match for people who need blood. It's far more likely that a Negro will get a transfusion from a White do-gooder than the other way around, which is not surprising.