While assessing the general health of the donor and throughout the donor history questionnaire, it may be determined that blood donation is not appropriate either for the safety of the donor and/or out of caution for the future recipient. In this case, the donor would be deferred from the process. Three types of deferrals exist: temporary, indefinite, and permanent.
A temporary deferral is when a person has to wait a specified amount of time before they are eligible to donate. For instance, if you donated a single unit of blood 6 weeks ago and were attempting to donate again, you would be deferred from donating for an additional 2 weeks (a total of 8 weeks from your last donation).
An indefinite deferral is when a person is excluded from donating for an unspecified amount of time. They may be eligible to donate in the future should regulatory requirements change and testing methodologies improve.
A permanent deferral is when a person is excluded from ever donating again.
In all deferral cases, autologous donations may still be permitted.
