Autologous

In biology, autologous refers to cells, tissues or even proteins that are reimplanted in the same individual as they come from. Bone marrow, skin biopsy, cartilage, and bone can be used as autografts.

In contrast, cells or tissues transplanted from a different individual are referred to as allogeneic or as an allograft.

Autologous blood donation
In blood banking terminology, autologous refers to a blood donation marked for use by the donor, often in an upcoming scheduled surgery.

The advantages of Autologous blood donation are:
 * Blood type will always match, even with a rare blood type or antibody type
 * The risk of infectious disease such as hepatitis or HIV is reduced, or not an issue.
 * Donations made in this way need not be tested for blood bone diseases
 * The risk of allergic reactions or incompatibility is reduced

The primary disadvantages are the significantly higher cost and the need to make all necessary arrangements well in advance. Autologous blood is stored at one specific hospital clearly labelled for use by one specific patient; if it is not used by that patient, it is discarded.

There is also a risk that, in an emergency or if more blood is required than has been set aside in advance, the patient could still be exposed to donor blood instead of autologous blood. Autologous donation is also not suitable for patients who are medically unable to or not advised to give blood, such as cardiac patients or small children and infants.

Bone autograft
In orthopaedic medicine, bone graft can be sourced from a patient's own bone in order to fill space and produce an osteogenic response in a bone defect. However, due to the donor-site morbidity associated with autograft, other methods such as bone allograft and bone morphogenetic proteins and synthetic graft materials are often used as alternatives.