AUTOLOGOUS AND DIRECTED BLOOD DONATIONS

Joseph E. Kiss, M.D., Associate Medical Director

INTRODUCTION

Central Blood Bank (CBB) has provided autologous donor services for over 20 years and directed donor services since 1987.  Well-defined advantages exist for autologous transfusions in that the potential for blood borne viral transmission, immunologic transfusion reactions, and sensitization are completely eliminated.  On the other hand, the rationale for directed donor transfusions stems largely from the perception among the public that blood obtained from persons they know may be safer than that from the regular volunteer donor population.  Based on prevalence studies of markers for blood borne viruses, however, physicians should be aware of the lack of objective evidence to support this opinion when considering transfusion options with their patients.

patient selection for autologous donations

Primary candidates are those undergoing planned surgery ordinarily requiring blood to be crossmatched.  A useful guide in estimating the number of units which should be drawn is the hospital’s maximum surgical blood order schedule (MSBOS).  Autologous donation is generally a safe procedure, even for elderly patients.  However, vasovagal reactions, which occur in 1-4% of all blood donations, may carry the risk of greater morbidity for some patients with cardiac or cerebrovascular disease.  CBB medical staff are available to assist with questions regarding donor suitability and the need for special monitoring.

AUTOLOGOUS DONATION PROCEDURE

Autologous units may be stored as whole blood, but are usually processed into packed red blood cells; fresh frozen plasma may also be prepared for the latter.  Liquid-stored red cells have a shelf life of 35-42 days.  Once a date for surgery is confirmed and the physician prescribes the number of units needed, patients may be scheduled at one of CBB’s fifteen Community Donor Centers in the area.  Because of the special medical value of autologous blood, certain regular donor eligibility criteria (e.g., donation  

interval, minimum hematocrit) are relaxed for autologous donors.  As a rule, donations are made at weekly intervals; the last donation should be no less than 72 hours before surgery to allow sufficient regeneration of the patient/donor’s red cells and blood volume.  Iron therapy is required since inadequate iron reserves is the major limitation to completing the donation schedule.  Should surgery be postponed, the hospital blood bank and CBB should be contacted so that the red cells may be frozen, if necessary.

Likewise, if an insufficient number of red cell units is collected due to hematocrit deferral (<33%) and the patient’s physician chooses to postpone surgery, the donated units may be frozen, permitting additional time to collect the prescribed amount.  In this way, the availability of autologous blood for surgery may be maximized.  Erythropoietin therapy has also been used for this purpose.

Directed donation procedure

Directed donors are in fact homologous donors, so the rigorous screening criteria used to safeguard both the health of the donor and the transfusion recipient are followed as for regular blood donors.  To allow time for donor scheduling, blood collection, processing (including testing), and shipping, as well as crossmatching at the hospital, directed donation requests require advanced planning.  None-the-less, in most cases directed donor units can be made available as little as 24-hours after donation.

policies

Directed donations between first-degree family members are gamma-irradiated in order to prevent transfusion-induced graft vs. host disease.  Unless notified otherwise by the patient’s physician, unused directed donor units may be “crossed-over” for general use.

All CBB autologous units are labeled “For Autologous Use Only”, since many of these units do not meet the stricter standards established for homologous blood.  CBB performs all regular donor testing on antilogous donations.  Because of the potential biohazard, units reactive for anti-HIV and HbsAg are discarded.  In instances where markers other than these are reactive, the patient’s physician determines whether to continue the donation schedule and appropriateness for transfusion.  Crossmatching is required on red cell units to confirm their identity before transfusion.

Copies of the Transfusion Medicine Update can be obtained by contacting Deborah Small at (412) 209-7320 or
by e-mail:  dsmall@itxm.org.