I e-mailed the HCBB, asking them to explain their policy which prevented me from being able to donate blood. This is their explanation. Note: it is only a sample of the letter they sent me.
"The regulations are numerous and center around two aspects of blood donation – patient and donor safety. These guidelines generally describe an interaction with donors which relies on verbal interaction from donors at critical points in the screening and blood collection areas.
However, let me also assure you that HCBB has a long-standing history of accepting donors for screening who are unable to speak, or where donor verbal interaction is difficult. In these situations, more emphasis is put on written communication and interaction. That’s the key – certainty that the donor understands the information and questions presented and is also able to respond as necessary. Since we have this history, I don’t feel our current policies or procedures need revision."