Washed red blood cells are

red blood cells Red blood cells (RBCs), referred to as erythrocytes (, with -''cyte'' translated as 'cell' in modern usage) in academia and medical publishing, also known as red cells, erythroid cells, and rarely haematids, are the most common type of blood cel ...

that have had most of the plasma,

platelets Platelets or thrombocytes () are a part of blood whose function (along with the coagulation factors) is to react to bleeding from blood vessel injury by clumping to form a blood clot. Platelets have no cell nucleus; they are fragments of cyto ...

and

white blood cells White blood cells (scientific name leukocytes), also called immune cells or immunocytes, are cells of the immune system that are involved in protecting the body against both infectious disease and foreign entities. White blood cells are genera ...

removed and replaced with saline or another type of preservation solution. The most common reason for using washed red blood cells in transfusion medicine is to prevent the recurrence of severe

allergic transfusion reaction An allergic transfusion reaction is when a blood transfusion results in allergic reaction. It is among the most common transfusion reactions to occur. Reported rates depend on the degree of active surveillance versus passing reporting to the blood ...

s that do not respond to medical treatment. The usual cause of these allergic reactions is proteins in the donor plasma. These proteins are removed by the process of washing the red blood cells.

Methods of washing red cells

There are multiple methods of washing red cells. These can include automated or manual methods. They can use

centrifugation Centrifugation is a mechanical process which involves the use of the centrifugal force to separate particles from a solution according to their size, shape, density, medium viscosity and rotor speed. The denser components of the mixture migrate ...

or centrifugation-free methods. The red cells can be re-suspended in saline or other types of special preservative solutions for red cells, such as SAGM (saline, adenine, glucose and mannitol).

Medical uses

Prevention of recurrence of severe allergic reactions

The most common reason for using washed red blood cells in transfusion medicine is to prevent the recurrence of severe

s. The allergen is usually a protein in the plasma that is removed by the process of washing the red blood cells. Various proteins, such as antibodies directed against

IgA IGA or IgA may refer to: Businesses and organizations * IGA (supermarkets) (initially Independent Grocers Alliance), a name used by many independent supermarkets throughout the world ** IGA (Australian supermarket group), the local Australian v ...

haptoglobin Haptoglobin (abbreviated as Hp) is the protein that in humans is encoded by the ''HP'' gene. In blood plasma, haptoglobin binds with high affinity to ''free'' hemoglobin released from erythrocytes, and thereby inhibits its deleterious oxidativ ...

in people with IgA and haptoglobin deficiency, have been suggested to have a causal relationship with the allergic reaction.

Cytokine Cytokines () are a broad and loose category of small proteins (~5–25 kDa) important in cell signaling. Cytokines are produced by a broad range of cells, including immune cells like macrophages, B cell, B lymphocytes, T cell, T lymphocytes ...

s and

chemokine Chemokines (), or chemotactic cytokines, are a family of small cytokines or signaling proteins secreted by cells that induce directional movement of leukocytes, as well as other cell types, including endothelial and epithelial cells. In addit ...

s, which accumulate during the storage of blood components, have also been suggested as causative agents. However, the literature is scarce and conflicting, as passive infusion of anti-IgA antibodies in to recipients has not been found to cause an allergic reaction.

Reduction in transfusion-related complications

In neonates, transfusion has been associated with an increased risk of serious side effects including: *

Necrotising enterocolitis Necrotizing enterocolitis (NEC) is an intestinal disease that affects premature or very low birth weight infants. Symptoms may include poor feeding, bloating, decreased activity, blood in the stool, vomiting of bile, multi-organ failure, and pot ...

(NEC) * Intraventricular haemorrhage (IVH) *

Retinopathy of prematurity Retinopathy of prematurity (ROP), also called retrolental fibroplasia (RLF) and Terry syndrome, is a disease of the eye affecting prematurely born babies generally having received neonatal intensive care, in which oxygen therapy is used beca ...

(ROP) * Chronic lung disease (CLD) * Death Transfusion-related immune modulation has been thought to be the underlying mechanism. Washing red cells has been thought to be one way of potentially decreasing the risk of theses transfusion-related side-effects. However, in neonates, there is insufficient evidence to say whether washing red cells has any effect.

Storage

Once red blood cells have been washed, they can only be kept for up to a day.

References

Blood cells {{treatment-stub Transfusion medicine