17.2 Red Cell and Whole Blood Therapy

17.2 Red Cell and Whole Blood Therapy

Quick Answer: One red-cell unit raises a stable ~70 kg adult about 1 g/dL hemoglobin and 3% hematocrit; children are dosed 10–15 mL/kg. Prestorage leukoreduced units are CMV-safe for most recipients. Irradiate cellular products when TA-GVHD risk is high. Issue hemoglobin S–negative units to neonates, intrauterine transfusion recipients, and patients with sickle cell disease. Give C/c, E/e, and K phenotype-matched (and more if alloimmunized) red cells to sickle and transfusion-dependent thalassemia patients. In emergency bleed, issue group O and switch to type-specific after two independent ABO determinations. Low-titer group O whole blood is a trauma balanced product. Hyperhemolysis in sickle cell disease is treated by stopping transfusion and giving immune therapy — not by blindly issuing more antigen-negative units.

This is June 9, 2026 outline V.B for red cells and whole blood. Manufacturing clocks live in Chapter 4. Thresholds live in 17.1. This section is which red-cell product and what increment to expect. If a stem asks 1 g/dL, emergency O, two ABO types, HbS-negative, phenotype matching, LTOWB, exchange, or hyperhemolysis, answer it here.

Expected increment

In a stable, nonbleeding, non-hemolyzing ~70 kg adult, one additive-solution unit raises hemoglobin about 1 g/dL and hematocrit about 3%. Failure to increment means bleeding, hemolysis, or a much larger patient — not a weak unit as the first explanation. Children and small adults are dosed by volume, commonly 10–15 mL/kg of red cells, which raises hemoglobin about 2–3 g/dL. Do not apply the 1 g/dL adult rule to a 12 kg toddler.

Check a post-transfusion hemoglobin after the unit is in and the patient is stable, not while blood is still on the floor. In ongoing hemorrhage the increment is a resuscitation vital sign, not a QC check on the bag. A washed or deglycerolized unit is a slightly smaller red-cell dose because cells are lost in the processor; still think in the same 1 g/dL order of magnitude for a full adult unit, then reassess.

CMV-safe and leukoreduced

Almost all U.S. allogeneic red cells are prestorage leukoreduced. Leukoreduction lowers febrile reactions, HLA alloimmunization, and CMV transmission. For CMV, a leukoreduced unit is considered CMV-safe and is accepted as equivalent to CMV-seronegative for most indications (AABB). Some obstetric and neonatal services still request both leukoreduced and CMV-seronegative for intrauterine transfusion or very-low-birth-weight neonates — follow the local protocol, but do not call leukoreduced CMV-unsafe.

Leukoreduction is not irradiation, not washing, and not hemoglobin S testing. A CMV-safe label does not make the unit phenotype-matched.

Irradiated red cells

Irradiation (typically 25 Gy to the center of the container) prevents transfusion-associated graft-versus-host disease by inactivating donor lymphocytes. Issue irradiated red cells for intrauterine transfusion and many neonatal exchange or simple transfusions after IUT; congenital cellular immunodeficiencies; Hodgkin lymphoma; recipients of purine analogues (fludarabine, cladribine, deoxycoformycin) and selected potent lymphodepleting therapies; hematopoietic progenitor cell transplant recipients (allogeneic and, in many programs, autologous); HLA-matched or crossmatch-compatible cellular products; directed donations from blood relatives; and all granulocyte concentrates.

Irradiation is not required for every oncology patient. Solid-tumor chemotherapy without the risks above is not an automatic irradiation indication. Irradiation shortens red-cell dating (often 28 days from irradiation or the original outdate, whichever is sooner) and raises supernatant potassium — relevant for large-volume neonatal transfusion (Chapter 4 and 17.4).

Hemoglobin S–negative and phenotype matching

Hemoglobin S–negative red cells are required for intrauterine transfusion, neonatal large-volume or exchange transfusion, and patients with sickle cell disease. Sickling of donor cells in a hypoxic, acidotic recipient — or in an exchange circuit — is the risk. A sickle-trait donor unit can sickle. Do not issue an untested unit to these patients because the antibody screen is negative.

Patients with sickle cell disease and transfusion-dependent thalassemia should receive red cells matched at least for C, c, E, e, and K from the first transfusion when feasible, and extended matching plus antigen-negative units once alloantibodies form. The goal is to prevent the next antibody, not only to win today’s crossmatch. RH genotyping matters because many patients of African ancestry have partial D, C, or e; a serologic e-positive unit may still stimulate an anti-e-like antibody. Antigen-matched does not treat hyperhemolysis (below).

Emergency group O, then type-specific

Uncrossmatched group O red cells are issued when delay will harm the patient. O-negative is reserved preferentially for women of childbearing potential and for children when inventory allows. O-positive is acceptable emergency stock for most men and for women beyond childbearing in modern trauma protocols — using O-negative for every adult male empties the rare inventory.

Switch to ABO type-specific (then fully crossmatched) as soon as the patient’s type is established. AABB requires two independent ABO determinations — two samples, or one sample plus a historical type that meets the facility’s computer-crossmatch rules — before a computer or abbreviated crossmatch. In a massive uncrossmatched resuscitation, switch when the type is confirmed and the blood bank can keep up; do not keep a group A patient on O-negative for twelve hours out of habit.

If the patient received so much group O that the reverse type is now mixed-field or shows anti-A or anti-B from the units, the blood bank may need to stay with O until the transfused isoagglutinins clear. That is a serologic decision, not a once-O-always-O slogan.

Low-titer group O whole blood and exchange

Low-titer group O whole blood (LTOWB) is used in civilian and military trauma as a balanced, oxygen-carrying hemorrhage product. Low titer means the donor’s anti-A and anti-B are below a defined threshold (many programs use < 50 or < 256 — program-defined, not an ASCP unpublished official titer). The unit is group O so it can go to any ABO recipient in an emergency. Cold-stored LTOWB is not a room-temperature platelet dose; it is a hemorrhage product that supplies red cells, plasma, and cold platelets together.

Exchange transfusion replaces the patient’s red-cell mass (and some plasma) to remove hemoglobin S, bilirubin, parasites (severe malaria), or incompatible antibody-coated cells (HDFN). In sickle cell disease, a full exchange often targets a post-procedure HbS commonly < 30% for stroke or severe acute chest — that target is a clinical protocol number, not a Board-owned cutoff. Automated RBC exchange needs antigen-matched, HbS-negative units and a plan for citrate and calcium.

Hyperhemolysis — stop, do not stack antigen-negative units

Hyperhemolysis is a sickle-cell (and occasionally thalassemia) syndrome in which post-transfusion hemoglobin falls below the pretransfusion value. Both donor and autologous cells lyse (bystander hemolysis). The DAT may be negative. The reticulocyte count often falls. Issuing better antigen-negative units feeds the process.

Management is stop transfusion unless the patient is imminently dying of anemia, give IVIG and corticosteroids, consider erythropoietin, and treat the trigger (infection, delayed serologic reaction). Further transfusion, if unavoidable, is a last resort after immune therapy is started — not the first reflex. This is the exam trap that looks like just find C-negative units.

Worked scenario. A 22-year-old woman with HbSS presents with hemoglobin 5.8 g/dL two days after two C-negative, e-negative, K-negative units. Pretransfusion hemoglobin was 7.4 g/dL. DAT is negative. This is hyperhemolysis until proven otherwise. Do not issue three more antigen-negative units as the first move. Stop, treat, and call the transfusion service medical director.

Exam traps. Increment is 1 g/dL / 3% Hct, not 3 g/dL. Leukoreduced is CMV-safe. Emergency O is temporary. Two independent ABO types before type-specific computer crossmatch. Hyperhemolysis: stop, not more matched units. LTOWB titer cutoffs are program-defined.