Chapter 16: Transfusion Medicine and the Blood Bank

INTRODUCTION

ROUTINE BLOOD DONATION

Voluntary blood donation provides all blood products that are transfused in the United States. Donors usually are >18 yr old, are in good health and afebrile, and weigh >110 lb (50 kg). Donors are usually limited to one unit every 8 wk and six donations per year. A variety of medical conditions and behaviors may temporarily or indefinitely exclude a donor from donating blood; these deferrals are intended to reduce the risk of transfusion-transmitted infections. Donor blood testing includes ABO/Rh type, antibody screen, HIV-1 and -2, HBV, HCV, Zika virus, HTLV-I and -II, and Treponema pallidum (syphilis). As of June 2020, the Red Cross began testing donated blood for COVID-19 antibodies. Donors who test positive for COVID-19 antibodies may be invited to donate convalescent plasma.

BLOOD GROUPS

Table 16-1 gives information on the major blood groups and their relative occurrences. For RBC units, type O is the “universal donor,” and AB is the “universal recipient.” For plasma units, type AB is the “universal donor” because it lacks both anti-A and anti-B, while type O is the “universal recipient.”

BLOOD BANKING PROCEDURES

Type and Screen (T&S): The blood bank tests the patient’s ABO and Rh type and screens for antibodies. If an alloantibody (an antibody formed in response to pregnancy, transfusion, or transplantation targeted against a blood group antigen that is not present on the person’s red blood cells) is found that would make crossmatching challenging, the ordering physician usually is notified. If the decision to transfuse is made before the specimen expires (typically 72 hr after collection), the T&S order may be changed to a T&C.

Type and Cross (T&C): The blood bank performs a T&S on the patient’s specimen and matches specific ...