Blood Bank

Packed RBC issued by the NEMC Blood Bank are leukoreduced and preserved using an anticoagulant and an additive solution of adenine saline.  Packed RBC stored with adenine saline have a shelf life of up to 42 days, and have a hematocrit of between 55 and 65%.

Except in an emergency situation, packed RBC must be crossmatched and irradiated before issue.

Washed RBC are available to patients who experience allergic transfusion reactions to packed RBC.

A unit of washed RBC is prepared from one unit of leukoreduced packed RBC.  Anticoagulant, preservative solution, isoagglutinins, plasma protein and extracellular potassium are all reduced to very low levels.  A unit of washed RBC has a hematocrit of between 55 and 65% and expires 24 hours after washing.

Using a cryoprotectant solution, a unit of packed RBC can preserved in the frozen state for up to ten years after collection.  After thawing, the glycerol must be removed by a process called deglycerolization.  (Freezing RBC also provides a way for the Blood Bank to preserve autologous RBC and RBC with rare phenotypes for up to ten years in the frozen state).

Glycerolization of RBC inactivates leukocytes.  Except in an emergency situation, deglycerolized RBC must still be crossmatched for an adult recipient and irradiated before issue.

Fresh frozen plasma (FFP) restores blood volume and replaces all coagulation factors.  By definition, one ml of FFP contains one international unit (iu) of each clotting factor.

Cryoprecipitated antihemophilic factor (cryo) is normally used to restore fibrinogen to patients who become fibrinogen deficient during rapid blood loss.  Cryo also contains factor XIII, factor VIII and von Willebrand's factor and can be used to treat hemophiliacs and von Willebrand's patients if the appropriate lyophilized clotting factors are unavailable.

Rapid blood loss, defects in platelet production or platelet destruction by the immune system can result in a platelet deficiency.

A single donor platelet (SDP) is equivalent to between six and eight random platelet concentrates.  The Blood Bank normally issues one SDP when 6–10 units of random donor platelets are ordered.  When small platelet doses are required, an SDP can be split into several aliquots.

SDP expire five days after donation.  A current clot is not required before SDP can be issued, but the Blood Bank must have a record of the patient's blood type

If necessary, platelets can be washed to prevent hive reactions.

Patients who fail to respond to platelet transfusion may benefit from receiving HLA matched platelets.

Normal serum albumin is used to replace blood volume, for plasma replacement during plasmapheresis, and to replace colloids in burn patients.

The Blood Bank provides albumin in 5% and 25% concentrations.

The following table lists lyophilized clotting factors provided by the Blood Bank and their indications:  

Note that the Blood Bank provides only recombinant products whenever possible.

Given the assay values of the available inventory, the Blood Bank will issue a number of vials that comes as close as possible to the ordered dose.

Physicians caring for patients who will require extended clotting factor support are urged to discuss the situation with the Blood Bank Medical Director (ext. 6454) as soon as possible.

Two formulations of Rh immune globulin are used at NEMC.  IV Rh immune globulin is used in the treatment of idiopathic thrombocytopenic purpura (ITP) and is only available from the pharmacy.  IM Rh immune globulin is available from the Blood Bank and is used to prevent Rh sensitization by removing Rh-positive RBC from the circulation of an Rh-negative patient after the patient has been exposed to a small amount of Rh-positive RBC.  In order to prevent hemolytic disease of the newborn Rh immune globulin should be given to a pregnant Rh-negative woman at 28 weeks gestation, after abnormal bleeding and within 72 hours following the birth of an Rh-positive baby. 

Each vial of Rh immune globulin contains enough antibody to clear 30 ml of Rh-positive RBC from the circulation of an Rh-negative recipient.  The Kleihauer-Betke acid elution test serves to quantify the number of fetal RBC in the maternal circulation (fetal RBC per 1000 maternal RBC.  The following formula can be used to estimate the volume of a fetal-maternal hemorrhage, and to calculate the number of Rh Immune Globulin vials required to treat a given FMH.

Acid Elution Result/1000 x Maternal Blood Volume = FMH        (5000 ml may be used as an estimate of Maternal Blood Volume)

For safety, the estimated FMH volume is doubled before calculating the number of Rh immune globulin vials required.

It is rarely useful to give more than 10 doses, no matter how large the FMH.

The following tests require 1, 10 ml EDTA purple top tube. 

Additional plasma may be required for antibody identification if the screen is positive.  Titration of the antibody is done only in selected cases. 

Depending on the recipient's immune status, one of two methods of crossmatching is used: the electronic (computer) crossmatch or the serologic (full) crossmatch.  A current (less than 72 hours old) Blood Bank specimen is required for either method.

The Direct Antiglobulin Test (DAT) is a test for antibody that has become bound to the surface of a patient's red blood cells.  The patient may become anemic if the antibody coated cells are recognized and destroyed by the immune system. 

1.  Some medications can negatively interact with the patient's immune system resulting in the production of an autoantibody that is absorbed onto the surface of the patient's red cells.  The Blood Bank requests a medication list to rule out this possibility. 

2.  The patient may have a disease associated with the production of an autoantibody.  The autoantibody may be either warm or cold reactive and may either be directed against a specific antigen or react with all red cells.  It may be difficult or impossible to find compatible RBC for patients with autoimmune hemolytic anemia.  If so, "least incompatible" RBC must be issued.

The final step in resolving a positive DAT result is to identify the specificity of the bound antibody by preparing an elution.

The Blood Bank will release group O Negative RBC without compatibility tests or antibody screening of the recipient in the following emergency situations:

1.  There is insufficient time to perform any pretransfusion testing, or no pretransfusion specimen is available, and the blood type of the patient is unknown.

2.  There is insufficient time to perform any pretransfusion testing, but a pretransfusion specimen over 72 hours old that has been drawn during the current admission is available, and the patient is known to be Rh-negative.

The Blood Bank will release group O Positive RBC without compatibility tests or antibody screening of the recipient in the following emergency situations:

1.  There is insufficient time to perform any pretransfusion testing, or no pretransfusion specimen is available and the patient's blood type is unknown, and O Negative blood is not available.

2.  There is insufficient time to perform any pretransfusion testing, but a pretransfusion specimen over 72 hours old that has been drawn during the current admission is available, and the patient is known to be Rh-positive.

The Blood Bank will release blood components without serologic tests for disease only when no alternative therapy is possible.  The Blood Bank Medical Director must specifically approve every release of serologically untested components.

The Blood Bank makes every effort to issue emergency blood products as quickly as is safely possible.  A Blood Bank Emergency Release Form must be completed and returned to the Blood Bank.

This procedure is needed to prepare a patient for bone marrow transplant.  Before collection, stem cells are lured out of the bone marrow into the peripheral blood by a special regimen of drugs (chemotherapy and growth factors, Neupogen), where they are called human peripheral blood progenitor cells (HPBPC) or peripheral blood stem cells (PBSC). 

PBSC are collected by an automated blood cell separator which centrifuges blood, separating the blood components and skimming off the stem cell layer for collection. 

The number of collections will vary from patient to patient based on several factors: the volume of the whole blood processed, the disease being treated, chemotherapy treatment, and response to growth factors.  Cells collected in a PBSC procedure are analyzed soon after the procedure to see if enough CD34 positive cells have been obtained to engraft the patient. 

PBSC collection is scheduled through the bone marrow transplant coordinator. (Foundation for the Accreditation of Hematopoietic Cell Therapy) accreditation.

Graft Versus Host Disease (GVHD) is a potentially fatal transfusion complication in which passenger donor lymphocytes present in some blood components engraft in a recipient, multiply and attack the recipient's tissues.  Both platelets and RBC components contain lymphocytes that are capable of causing GVHD.  Neonatal patients, patients with compromised immune systems and recipients of donor-specific blood that has been donated by a primary relative are at increased risk of GVHD.

Leukoreduction alone does not prevent GVHD, but blood product irradiation completely stops lymphocyte engraftment.  At NEMC, except in an emergency situation, all platelets and RBC components are irradiated before issue. 

Leukocytes present in platelets, packed RBC and washed RBC can cause febrile transfusion reactions, can immunize recipients against leukocyte antigens, and can transmit cytomegalovirus (CMV) infection.   Immunization against leukocyte antigens can shorten the survival time of transfused platelets and complicate a future transplant.  CMV infection can be fatal to premature infants and to patients with compromised immune systems.   At NEMC, except in an emergency situation, all heterologous packed RBC, washed RBC and platelets are leukoreduced before issue.

Freezing and deglycerolization inactivates passenger leukocytes, so deglycerolized RBC are not leukoreduced before issue.

Outpatient blood transfusions are provided for all departments except the Hematology/Oncology Clinic.  Patients are in the clinic for approximately 3-4 hours depending on the products given.  No more than three blood products are given in a day.  Packed red blood cells are transfused over 45-60 minutes per unit, platelets over 30-45 minutes per unit, and FFP over 45 minutes per unit.  All procedures are by appointment only. 

Donor lymphocyte (DLI) collection, therapeutic plasmapheresis (TPE), leukapheresis, plateletpheresis, and red blood cell exchange are provided by the Blood Bank Clinic.  These procedures are performed on an outpatient and inpatient basis.  They are done either in the Blood Bank Clinic, ICUs or patient floors, which is dictated by the patient’s condition.  

Therapeutic apheresis is the removal of a specific blood component from a patient for the purpose of depleting that pathogenic component from the patient's circulation, such as autoantibodies and immune complexes.  The remaining blood components are continuously returned to the patient.  Therapeutic apheresis procedures usually fall into the following categories: cell depletion (leukapheresis and plateletpheresis), plasma exchange or red cell exchange.

Therapeutic plasma exchange is used to treat immune-related disorders predominately in four medical specialty areas: Neurology, Nephrology, Hematology, and Rheumatology.  Therapeutic plasma exchange is performed to remove an offending antigen, antibody, immune complex or other circulating toxic substance in the plasma.   Large quantities of plasma can be removed quickly and safely replenished with the prescribed protein replacement fluid. 

Therapeutic Phlebotomy

Therapeutic phlebotomy is the removal of 500 cc (approximately 1 pint) of blood, but 250 cc may be indicated in the elderly, those with cardiovascular disease or low weight.  This is performed on an inpatient and outpatient basis.  This procedure takes approximately 45 minutes.  All procedures are by appointment only.

Any undesirable effect following a blood component transfusion is a transfusion reaction.  Nursing policies and procedures govern the standards for identifying a transfusion reaction.  When a transfusion reaction is reported, the Blood Bank performs a transfusion reaction workup to determine whether the reaction was caused by red cell immunity.   A negative transfusion reaction workup result does not mean that a reaction did not take place.  It only means that the Blood Bank was unable to demonstrate that the reaction was caused by red cell immunity.

Hemolytic reactions involve the destruction of red blood cells.  Immediate hemolytic reactions are most often caused by repeat exposure to an antigen against which the patient has previously developed the corresponding antibody. 

Intravascular hemolytic reactions are most serious type of transfusion reaction, are and are usually caused either by RBC transfusion of the wrong blood type or by a failure of pretransfusion testing to inaccurately identify an a potent red cell antibody.

Nonhemolytic febrile reactions can occur in recipients who have been immunized against leukocyte antigens. 

Nonhemolytic allergic (hives) reactions can occur in recipients who have been immunized against plasma proteins. 

A recipient who is IgA deficient and who also produces class-specific anti-IgA may experience an nonhemolytic anaphylactic reaction to the IgA found in blood components containing plasma. 

Nonimmune transfusion reaction effects include bacterial contamination, circulatory overload, citrate toxicity and iron overload.