TRANSFUSION SERVICES (BLOOD BANK)



TRANSFUSION SERVICES (BLOOD BANK)

Introduction

The Christiana Care Health Services maintains a Blood Bank and Transfusion Service. This section on Transfusion Therapy is designed to inform the Christiana Care Health Services staff of services provided by the Blood Bank Department and provide guidelines for transfusion. The "Circular of Information for the Use of Human Blood & Blood Components" and "Blood Transfusion Therapy -A Physician's Handbook" are available in the Blood Bank and should also be consulted for additional information.

Indications for Transfusion Therapy

Transfusion therapy with red blood cells (RBCs) is indicated for restoration of oxygen carrying capacity and correction of anemia. Most patients are not significantly symptomatic until the hemoglobin level is less than 7-8 grams/dl, however factors such as cause for the anemia and comorbid illnesses are considered in each transfusion decision. Platelets are indicated for correction of significant thrombocytopenia with bleeding, for prophylaxis in profound thrombocytopenia (usually less than 10,000), or for patients with thrombopathies. FFP and cryoprecipitate may be indicated for correction of coagulation defects in certain circumstances. All transfusion decisions involve integration of the clinical information and laboratory data and reflect both the benefit and risks of the therapy.

Definitions and Explanation of Terms

Blood Bank - A laboratory which is responsible for the collection, processing, manufacture, and storage of human blood and its components.

Transfusion Service - A laboratory which is responsible for testing patient samples, storage of blood products, and issuing products for transfusion.

Transfusion Therapy - The infusion of blood or one of its components for therapeutic purposes.

Order - Formal written instructions from a physician which appear on a patient chart or on a prescription form requesting services and/or products.

Request - The act of asking to supply products or services as a result of the physician's order.

Transfusionist - A physician or registered nurse specially trained in transfusion practices who performs the phlebotomy and/or starts to transfuse the blood or blood component. Only the transfusionist may break the seal of the unit.

Transfusion Reaction - Any untoward effect resulting from a transfusion. All suspected reactions must be reported to the patient's physician and the Transfusion Service Lab (Blood Bank) and/or IV nurses at the time it is noted.

Unit Label - The non-removable label on the front of the blood or blood component containing information regarding the contents of that unit.

Requisitions

All Transfusion Service Laboratory (TSL) tests can be ordered by using a manual Transfusion Service Laboratory Requisition (the red and white form #18821 S) or by the Clinical Care System (CCS).

All manual requisitions must be stamped with an addressograph plate or the information normally found on the plate must be legibly handwritten. The physician's order must be transcribed in the space provided on the requisition for requesting blood and blood components.

Both types of requisitions (manual and CCS) have a space for the signature of the phlebotomist. Each specimen sent to the Blood Bank must be accompanied by one of the requisitions. The only exception to this would be immunology tests ordered through the CCS. No testing will be performed unless the specimen and a properly signed slip have been received and all patient identification information match.

Services Provided by the Transfusion Service Lab

Diagnostic

Hepatitis Markers - tests for infectivity and/or evidence of prior exposure to the viruses (viral antibodies)

HBsAg and confirmation - used to detect the presence of the Hepatitis B surface protein in the serum.

Anti-HBc - detects the antibody to the Hepatitis B core antigen which is present in nearly all chronic HBsAg carriers.

Anti-HBs - detects the antibody to HBsAg and usually indicates immunity to Hepatitis B virus.

Anti-HCV - detects the antibody to the Hepatitis C virus previously called non-A, non-B hepatitis.

Anti-HAV(IgM) - used to detect the IgM class antibody to Hepatitis A that appears during the acute phase of infection and persists through early convalescence.

Anti-HBc(IgM) - used to detect the IgM class antibody to the Hepatitis B core antigen. It is a reliable marker for acute disease and can be valuable for diagnosing post-transfusion Hepatitis B.

Immunologic Tests

Anti-HIV I/II - detects antibodies to human immunodeficiency viruses type 1 and/or type 2 which cause Acquired Immunodeficiency Syndrome (AIDS).

Rapid HIV – detects antibody to HIV 1 only. Limited to needlestick/exposures through Employee Health and untested mothers in L&D.

Anti-HTLV-I/II - detects antibodies to the human T-lymphotropic virus type I/II which has been associated with Adult T-cell leukemia.

CMV - semi-quantitative measurement of IgG antibodies to cytomegalovirus in serum to indicate past or current infection.

Rubella - quantitative measurement of IgG antibodies to the Rubella Virus in serum to aid in the determination of immune status.

Toxoplasma - quantitative measurement of IgG antibodies to Toxoplasma gondii in serum to aid in the determination of immune status.

Send Out Tests - tests sent to facilities outside the hospital.

HAV - antibody to Hepatitis A virus. This combination test detects IgM and IgG antibodies.

HDV - antibody to Hepatitis Delta virus.

HBeAg - detects Hepatitis B envelope antigen.

Anti-HBe - antibody to HBeAg

HCV PCR - Hepatitis C by polymerase chain reaction method, qualitative test.

HCV RIBA - Hepatitis C by radio-immunoblot assay

HCV RNA - Hepatitis C ribonucleic acid, quantitative test.

HIV I and HIV II Western Blots - confirmatory test for HIV I and HIV II that detects viral gene proteins.

HTLV I/II Western Blot - confirmatory test for HTLV I/II

Rubella IgM - measurement of IgM antibody

CMV IgM - measurement of IgM antibody

Toxo IgM - measurement of IgM antibody

Antibody Titer

Titration is a semi-quantitative measurement of the amount of antibody contained in a serum; the higher the titer, the more antibody present. The serum is diluted serially until the antibody can no longer be detected and the titer is reported as the reciprocal of the highest reactive dilution.

Both autoantibodies and allo-antibodies may be titered. Cold (auto) agglutinin titer may be elevated in the serum of patients with certain diseases; for example, an elevated titer (greater than 32) in a patient with respiratory symptoms may be indicative of mycoplasma infection. Serial titers of autoantibodies may be employed to assess response to therapy. Allo-antibodies such as the naturally occurring isoagglutinins anti-A and anti-B are sometimes titered in assessing immune competence.

Cold antibodies are usually complete (IgM) antibodies with a blood specificity of Anti-I. Titers less than or equal to 32 are of no significance. In patients with acquired hemolytic anemia associated with a cold antibody, the titer is usually in the thousands. Elevated cold agglutinin titers are also seen in primary atypical pneumonia.

The most frequent use of the antibody titer is to follow serially the response of each allo-antibody to a red blood cell antigen found in the mother's serum during pregnancy. If the antibody is of IgG structure and directed against a red cell antigen inherited by the baby from its father, the possibility for Hemolytic Disease of the Newborn (HDN) exists. Rh HDN is the most common. Antigen-positive red cells from the baby will usually stimulate the mother to produce more antibody, producing a rising titer.

Special Collection for Cold Agglutinin

Blood should be collected in a prewarmed (37o C) purple top vacutainer tube immediately placed in a cup of warm (37o C) water and taken directly to the Blood Bank.

Direct Antiglobulin Test (DAT)

The DAT is used to detect globulins immunologically bound to the patient's red cells in vivo. The test is used in the diagnosis of hemolytic disease of the newborn, autoimmune hemolytic anemia, investigation of transfusion reactions, and diagnosis of drug-induced red cell sensitization reactions. A cell eluate may be performed when the DAT is positive in order to determine the identity of the antibody coating the cell. An eluate is the solution recovered after attempting to remove antibodies from red blood cells. Several techniques are available and the technique used will depend on the circumstances in each case. After an eluate is prepared, it is tested in the same manner as serum to detect antibodies. Occasionally a cell eluate may demonstrate the presence of an antibody coating the cell which cannot be detected by performing a routine antibody screen. The test is also used in investigation of transfusion reactions if the DAT becomes positive after the patient has been transfused.

Antigen Profile

The profile consists of typing the patient's cells for common antigens in the ABO, Rh, Kell, Kidd, Duffy, MNS, Lewis and P blood group systems for which antisera are available. Patients whose cells lack antigen in any of these systems have the potential to produce antibodies against those antigens if the patient receives blood possessing those antigens. When the DAT is positive, the extent of typing in the profile is reduced. An antigen profile is suggested for anyone expected to receive serial transfusions over a long period of time such as patients with renal disease, malignancies, chronic anemia, or other blood dyscrasia.

Transfusion Reaction Evaluation

Any symptoms suggestive of a transfusion reaction during or after a transfusion must be reported to the physician and the Transfusion Service Lab for investigation. Post transfusion samples must be drawn immediately. The investigation is a stat work-up consisting of 1) a clerical check for errors, 2) inspection of plasma for hemolysis, 3) a DAT, and 4) visual inspection of a post transfusion urine specimen. Any indication of a hemolytic reaction will result in additional tests being performed. Please refer to Adverse Reactions to Transfusions.

Platelet Antibody Studies

The Blood Bank sends testing for post-transfusion purpura (PTP) and Neonatal Alloimmune Thrombocytopenia (NAIT) to the Red Cross. The majority of PTP cases are associated with anti- PLA1 antibodies, although other specificities do occur. Antibodies are detected during the acute phase of thrombocytopenia, and platelet antigen typing is completed when the patient's platelet count recovers. NAIT is caused by passive transfer of maternal antibody to the newborn. The mother's serum is tested against the platelets of the father and a panel of known, typed platelets. Specificity is often found to be anti-PLA1, but specificities with Bak, Yuk, Br, and HLA are reported.

HLA ABC and DR typing and HLA Cytotoxic Antibody Testing

HLA ABC and DR typing is usually performed on potential bone marrow transplant candidates. HLA ABC and HLA cytotoxic antibody testing is usually performed on patients about to undergo chemotherapy for possible HLA matched platelet pheresis support in the event the patient becomes refractory to platelet transfusions. Testing requires a calculation of the number of tubes to be drawn based on the patient white count. Advance scheduling is also required. It is therefore necessary to contact the blood bank prior to ordering testing.

Pretransfusion

Neonatal Typing

Tests performed include ABO, Rh, and DAT. Neonatal Typing should be ordered when sending cord bloods or other specimens for testing of neonates or infants less than four months of age.

Type and Screen

This is not an order to perform compatibility testing, but to perform all testing required (ABO, Rh, and antibody screen) prior to compatibility testing. Compatibility tests will only be performed when there is a physician's order for transfusion.

Type and Crossmatch

This test includes ABO, Rh, antibody screen, and crossmatch of blood for transfusion. The physician's order to transfuse or crossmatch blood for the patient must be written as it appears on the chart.

Rh Immune Globulin (RhIg) Evaluation

Antepartum, amniocentesis, or termination of pregnancy - This work-up is performed to evaluate the need for giving Rh Immune Globulin (RhIg) and consists of an ABO and Rh and antibody screen. All pregnant Rh negative women should be evaluated as candidates to receive RhIg.

Postpartum - After delivery, the newborn's blood type will be determined. If the baby is Rh negative, the mother does not need a RhIg Evaluation. If the baby's type is Rh positive or cannot be determined, the mother is a RhIg candidate and a postpartum sample must be collected. This sample will determine if the mother should receive more than one dose of RhIg.

Therapeutic Products

See "Circular of Information for the Use of Human Blood and Blood Components" (prepared by AABB and ARC) or specific product circulars for commercially prepared products. The last ten products in this section (12-21) are commercially prepared.

Red Blood Cells (Leukopoor)

The red cells from a unit of whole blood that have been filtered to remove >99% of leukocytes. Leukocyte-poor RBC's are used routinely for all RBC transfusions. Storage may be up to 42 days at 4oC depending on the coagulant used when drawing the unit.

Red Blood Cells (Washed)

The red cells from a unit of whole blood that have been washed and resuspended in normal saline. Washed cells contain little or no serum proteins. After a unit has been washed, it can be stored for only 24 hours at 4 oC. This product may only be ordered after consultation with the Blood Bank Medical Director.

Red Blood Cells (Deglycerolized)

The red cells from a unit of whole blood that have been glycerolized and stored frozen up to ten years. Prior to transfusion, the unit is thawed, deglycerolized, and washed. Deglycerolized cells contain reduced numbers of leukocytes and little or no serum proteins. After deglycerolization, the unit can be stored for only 24 hours at 4oC. This product may only be ordered after consultation with the Blood Bank Medical Director.

Autologous Blood

Autologous transfusion refers to the transfusion of blood or blood components to the same person who donated the blood. Patients wishing to donate autologous blood are referred to the Blood Bank of Delaware. (A physician order is required.) The donor center then delivers autologous units to the appropriate hospital. These units are kept in inventory until they expire. Each unit donated for autologous use shall have a special tag permanently attached to the unit. A tag with the heading, "Autologous Unit – For Autologous Use Only" indicates that the unit is not acceptable for allogeneic transfusion.

Designated Donation

Designated donations are units drawn for transfusion to a specific patient, usually from family members or friends of the patient. A tag with the heading, "Designated Donation" and the patient's name and date of birth will be attached to the bag. Designated donors are tested for infectious disease markers, therefore 72 hours is required before blood is available to allow for testing. A husband is not recommended as a directed donor for his wife of child bearing age. If the wife receives this blood, she may produce antibodies that may affect future babies and cause hemolytic disease of the newborn. Designated donors are not collected at Christiana Care. These donors are referred to the Blood Bank of Delaware.

Platelets (Apheresis, HLA-matched, Random Donor Pools)

Platelets for transfusion are obtained by donor platelet pheresis. Rarely, and only with the approval of the Blood Bank Medical Director, pools of six random donor platelets prepared from individual units of donated whole blood may be provided. For adults, ABO-compatible platelets are preferred, but are not essential. Platelets are not routinely crossmatched, however, crossmatching is required if the platelet product contains more than 5 ml of red cells. Platelets can be stored for up to five days after collection.

Platelet pheresis products are now tested for bacterial contamination before being delivered from the Blood Bank of Delaware. Testing is initiated before the products are sent, but results may not be available before the platelets are transfused. Should a pheresis product test positive for bacteria, the blood center will notify our Blood Bank. Our Blood Bank will quarantine the product, as well as notify the physician if the product has been transfused.

Platelet pheresis is an effective way to harvest a therapeutic adult dose of platelets from one individual donor. Platelet pheresis should contain 3x1011 platelets, and the plasma volume will vary between 200 and 500 ml.

If approved by the Blood Bank Medical Director, six random donor platelet concentrates may be pooled for transfusion. Each individual platelet contains not less than 5.5x1010 platelets in 50-70 ml of plasma. The pool of six platelet concentrates should, therefore, contain no less than 3x1011 platelets suspended in 300-420 ml of plasma. Once the pool is prepared, this product expires in four (4) hours. The platelet concentrates in each pool are tested for bacterial contamination before being issued.

If the plasma volume of the platelets is considered excessive the product may be centrifuged to permit removal of the undesirable plasma. Following this centrifugation, the platelets must rest for 1 hour without agitation, then be gently agitated for 1 hour to assure the resuspension necessary for optimum function and survival before they can be transfused. This two-hour delay must be considered by the physician when requesting reduced volume platelet transfusions.

HLA matched platelet pheresis may be requested from the blood bank for patients who demonstrate refractoriness to platelet transfusion. The products are obtained by the blood bank from Penn Jersey American Red Cross and require scheduling of product and preliminary HLA A,B, and C typing, and tests for HLA cytotoxic antibodies.

A one (1) hour post-transfusion platelet count is recommended after each platelet transfusion. This count should be used to determine the correct platelet increment for the patient, and helps determine how the patient responded to the platelet transfusion.

When Rh positive platelets are transfused to Rh negative females of childbearing age ( ................
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