- Stored specimens and HLA testing: Stored blood and tissue samples from patients will be used for future research on HIV, AIDS and related medical conditions, and the immune system. The samples may be labeled with no identifying information, with identifying information, such as the patient's name, or with a code that only the study team can link to the patient. Some of the blood drawn may be used for HLA typing, a genetic test of markers of the immune system. Usually used to match bone marrow or organ transplants, HLA type might also be used to try to identify factors associated with the progression of HIV disease or related conditions. Determining HLA type is also necessary to be able to perform certain research studies.