Blood Typing, Antibody Screen, and Crossmatch Core Lab Study
Synonym/Acronym
ABO group and Rh typing, blood group antibodies, crossmatch (XM), type and screen (T&S), type and crossmatch.
Rationale
To identify ABO blood group and Rh type, typically for prenatal screen and transfusion purposes. These tests are also used to help establish compatibility for cellular therapy and solid organ transplantation (in addition to human leukocyte antigen [HLA] and HLA antibody typing).
A small group of studies in this manual have been identified as Core Lab Studies. The designation is meant to assist the reader in sorting the basic “always need to know” laboratory studies from the hundreds of other valuable studies found in the manual—a way to begin putting it all together.
Normal, abnormal, or various combinations of core lab study results can indicate that all is well, reveal a problem that requires further investigation with additional testing, signal a positive response to treatment, or suggest that the health status is as expected for the associated situation and time frame.
Blood product transfusion carries significant risks for patients, up to and including death. It’s crucial for nurses to understand the ABO/Rh systems and to follow their facility’s transfusion policies and procedures for the administration of different types of blood products. Blood typing and other core lab tests such as TBil, H&H, platelet count, and WBC count are valuable tools used to evaluate and monitor patients before, during, and after transfusion. Blood typing is included in the obstetric panel.
Patient Preparation
There are no food, fluid, activity, or medication restrictions unless by medical direction.
Normal Findings
(Method: FDA-approved reagents with glass slides, glass tubes, gel, or automated systems) Compatibility (no clumping or hemolysis).
Timely notification to the requesting health-care provider (HCP) of any critical findings and related symptoms is a role expectation of the professional nurse. A listing of these findings varies among facilities.
Signs and symptoms of blood product transfusion reactions range from mildly febrile to anaphylactic and may include chills, dyspnea, fever, headache, nausea, vomiting, palpitations and tachycardia, chest or back pain, apprehension, flushing, hives, angioedema, diarrhea, hypotension, oliguria, hemoglobinuria, acute kidney injury, sepsis, shock, and jaundice. Complications from disseminated intravascular coagulation (DIC) may also occur.
An IgA deficiency mediated transfusion reaction is a relatively rare type of anaphylaxis. It has been observed when an IgA deficient blood product recipient is transfused with a blood product containing anti-IgA antibodies. The reaction usually occurs within 1 hr of transfusion. A reaction does not occur in all patients with an IgA deficiency and the reaction can occur along a spectrum ranging from no symptoms or adverse reaction to full-blown, life-threatening anaphylaxis. Commonly transfused blood products (FFP, RBCs, platelets) contain small amounts of plasma.
Possible interventions in mildly febrile reactions include slowing the rate of infusion, then verifying and comparing patient identification, transfusion requisition, and blood bag label. The patient should be monitored closely for further development of signs and symptoms. Administration of epinephrine may be ordered.
Possible interventions in a more severe transfusion reaction may include immediate cessation of infusion, notification of the HCP, keeping the IV line open with saline or lactated Ringer solution, collection of red- and lavender-top tubes for post-transfusion work-up, collection of urine, monitoring vital signs every 5 min, ordering additional testing if DIC is suspected, maintaining patent airway and blood pressure, and administering mannitol.
Study type: Blood collected in a red-top, lavender-top [EDTA], or pink-top [K2EDTA] tube; related body system: .
Blood typing is a series of tests that include the ABO and Rh blood-group system performed to detect surface antigens on red blood cells (RBCs) by an agglutination test and compatibility testing to determine antibodies against these antigens. There are eight known blood types comprised of four main blood groups (A, B, AB, and O) and two Rh types (negative and positive).
Main Blood Group Identification
In ABO blood grouping, the patient’s RBCs mix with anti-A and anti-B sera, a process known as forward grouping. The process then reverses, and the patient’s serum mixes with type A and B cells in reverse grouping. Individuals with A antigens have group A blood; those with B antigens have group B blood. Individuals with both A and B antigens have group AB blood (universal recipient); those with neither A nor B antigens have group O blood (universal donor). Blood group and type are genetically determined. After 6 mo of age, individuals develop serum antibodies that react with A or B antigen absent from their own RBCs. These are called anti-A and anti-B antibodies.
Rh Type Identification
Major antigens of the Rh system are D (or Rho), C, E, c, and e. Individuals whose RBCs possess D antigen are called Rh-positive; those who lack D antigen are called Rh-negative, no matter what other Rh antigens are present. Individuals who are Rh-negative produce anti-D antibodies when exposed to Rh-positive cells by either transfusions or pregnancy. A significant transfusion reaction will likely result if Rh-positive blood is subsequently administered to the sensitized Rh-negative recipient. The second instance of alloimmunization occurs when anti-D antibodies from an Rh-negative mother cross the placenta to the Rh-positive fetus’s RBCs and can cause hemolytic disease of the newborn.
Laboratory protocols for “weak D” testing have always been required as part of the compatibility process for transfusions; it is optional for certain other patient populations, most notably for obstetric patients. Obstetric patients with the “weak D” phenotype by serotyping are reported as RhD negative as a means of ensuring they receive Rh(D) immune globulin RhoGAM intramuscular (IM) or Rhophylac IM or IV, thus protecting them from inadvertent alloimmunization by an RhD positive fetus. Administration of RhIG (Rh immune globulin) to these candidates is not harmful. The advent of molecular technology has led to blood group genotyping (BGG). RhD genotyping offers the advantages of avoiding unnecessary injections of RhIG and transfusion of Rh-negative blood when Rh-positive products could be safely used instead. Alloimmunization may still occur in Rh-negative typed women as an unintended consequence of RBC transfusion, unknown miscarriage, or failure to receive the recommended RhIG protocol.
The inheritance pattern of the RhD antigen is autosomal dominant; homozygotes (DD) will always pass the RhD antigen gene on to their offspring and heterozygotes (Dd) will pass the RhD antigen gene to their offspring with a probability of 50%. RhD genotyping is recommended when there is a discrepancy in testing for any patient expected to receive a transfusion (due to variability in reagent system sensitivity or when findings at various points in testing are discordant, e.g., immediate spin stage is negative but IAT is positive) or when a subject’s Rh type is unknown (e.g., paternity cannot be positively confirmed at the time an RhD negative mother undergoes her prenatal blood work).
RBC Compatibility Testing
Generally, only blood with the same ABO group and Rh type as the recipient is transfused because the anti-A and anti-B antibodies are strong agglutinins that cause a rapid, complement-mediated destruction of incompatible cells. However, blood donations have decreased nationwide, creating shortages in the available supply. Safe substitutions with blood of a different group and/or Rh type may occur depending on the inventory of available units. Many laboratories require consultation with the requesting HCP prior to issuing Rh-positive units to an Rh-negative individual.
The type and screen (T&S) procedure is performed to determine the ABO/Rh and identify any antibodies that may react with transfused blood products. The T&S may take from 30 to 45 min or longer to complete depending on whether unexpected or unusual antibodies are detected. Every unit of product must be crossmatched against the intended recipient’s serum and RBCs for compatibility before transfusion. Knowing the ABO/Rh and antibody status saves time when the patient’s sample is crossmatched against units of donated blood products. Efforts are under way to develop a national registry (database) of RBC alloantibodies; a daunting but important patient safety initiative.
There are three crossmatch procedures. If no antibodies are identified in the T&S, it is permissible to use either an immediate spin crossmatch or an electronic crossmatch, either of which may take 5 to 10 min to complete. If antibodies are detected, the antiglobulin crossmatch procedure is performed, along with antibody identification testing, or the process is repeated, beginning with the selection of other units for compatibility testing. Typically, specimens for T&S can be held for 72 hr from the time of collection for use in future crossmatch procedures. This time frame may be extended for up to 14 days for patients with a reliably known history of no prior transfusions or pregnancy within the previous 3 mo. Laboratories work closely with HCPs in order to efficiently manage blood product inventory and many facilities have a transfusion committee comprised of physicians and laboratory personnel who specialize in blood banking. Policies based on evidence-based studies have been developed to reduce unnecessary and ineffective use of blood products. Requests for type and crossmatch are discouraged in some situations, such as when patients are undergoing procedures with: expected minimal blood loss, a historically low percent of transfused blood products, or a low ratio of transfused units to patients.
ABO and Rh testing is also performed as a prenatal screen in pregnant women to identify the risk of hemolytic disease of the newborn. Although most of the anti-A and anti-B activity resides in the immunoglobulin M (IgM) class of immunoglobulins, some activity rests with immunoglobulin G (IgG). Anti-A and anti-B antibodies of the IgG class coat the RBCs without immediately affecting their viability and can readily cross the placenta, resulting in hemolytic disease of the newborn. Individuals with type O blood frequently have more IgG anti-A and anti-B than other people; thus, ABO hemolytic disease of the newborn will affect infants of type O mothers almost exclusively (unless the newborn is also type O).
Other Types of Compatibility Testing
Many of the same tests used to determine the compatibility and safety of blood products (ABO, Rh, antibody screen, and infectious disease markers) are also used to establish a safe, compatible transplantation between donors and recipients of cellular therapy and solid organs. Cellular therapy uses human cells, such as bone marrow or stem cells, from a donated source to replace or repair damaged cells in a human recipient; solid organ transplantation serves a similar purpose, most commonly with heart, kidney, liver, lungs, pancreas, and skin.
Tissue typing, also called HLA typing, is additional testing performed to match a compatible donor and recipient for cellular therapy or solid organ transplantation. Blood cell antigens and tissue type are inherited, half from each of the biological parents. The individual antigens and tissue surface antigen patterns are specific for each person and are unique except in the case of identical twins. HLA typing is also performed to identify antibodies the recipient may develop against the donor’s foreign tissue cells in order to prevent graft versus host rejection. Although it is possible to find a compatible, non-related, donor-recipient pair in the general population, donor compatibility is best matched to a recipient who shares some of the same genetic markers—in other words, a person who is a blood relative.
All donated blood products are tested for ABO group, Rh type, unexpected RBC antibodies, and six transmissible infectious diseases; some of which may require the use of multiple methods for: hepatitis B core antibody (antibodies directed against the hepatitis B core antigen), hepatitis B surface antigen, hepatitis B virus (viral DNA by nucleic acid amplification testing [NAAT]), hepatitis C antibody, hepatitis C virus (viral RNA by NAAT), HTLV I and II antibody, HIV 1 (viral RNA by NAAT) and 2 antibody, Treponema pallidum antibodies (syphilis), and West Nile virus antibody (viral RNA by NAAT). In May 2021 the Food and Drug Administration (FDA) determined that the Zika virus no longer had sufficient prevalence to affect the pool of potential donors and was no longer on its list of “relevant transfusion-transmitted infections” and thereby no longer required testing. Blood centers were advised that they could discontinue testing for Zika after written notification was submitted to the FDA documenting the date Zika antibody testing was discontinued. Additional testing may be performed in cases of specific need to identify cytomegalovirus antibody, IgA deficiency, Trypanosoma cruzi antibody (all first-time donors; negative results on either current or at least one previous test), and Babesia (DNA by NAT and antibody for B. microtion donations where the Babesia protozoan is endemic). All donated units receiving additional testing will be labelled with the results (positive or negative).
Blood product transmitted CMV infections are a major cause of post transplant organ rejection, organ failure, and mortality; organ transplant failure is a very negative and costly outcome on a number of levels. Approaches to mitigate risk of blood product transmitted CMV infections include testing to identify IgG antibodies, use of a combined test for IgG and IgM antibodies to CMV, and use of leukoreduced blood products (CMV is harbored within WBCs). Conventional testing methods include enzyme immunoassay, indirect hemagglutination, and latex agglutination; FDA-approved testing systems for donor screening include a solid-phase red-cell-adherence test system and a passive particle agglutination test system. Practices vary by institution; some use an additional approach, which includes preemptive serial testing for viral antigens and prophylaxis with antiviral agents (i.e., ganciclovir, valganciclovir).
Note: All platelet donations are tested for bacterial contamination. The risk of a septic transfusion reaction related to platelet infusion is now greater than the risk of transfusion-transmitted viral infections. It is believed that a contributing factor is the storage temperature (22°C) of platelets which is favorable for bacterial growth. The most commonly identified bacterial groups include gram positive skin contaminants such as Staphylococcus aureus and Staphylococcus epidermidis. Some blood centers are now using an FDA-approved pathogen reduction system. The system uses a photoactive crosslinking compound and UVA light to inactivate the DNA and RNA of a wide variety of pathogens (bacteria, protozoa, viruses) in platelet products.
Licensed testing for emerging transmissible pathogens is not always available when the pathogens are identified. Therefore, blood component collection facilities implement a variety of strategies to help ensure the safety of the blood supply. Recommendations may include the addition of specific questions to the donor history questionnaire to evaluate risk of infection, implementation of a waiting period prior to donation, or deferral of donation. Decisions regarding donor eligibility are based on criteria and recommendations developed by national (e.g., AABB, FDA, Centers for Disease Control and Prevention) and international (e.g., World Health Organization) scientific communities. Educational material is also available at collection facilities for potential donors to review and determine whether they should self-defer from donation.
Common Types of Mild Transfusion Reactions (Also Refer to the Critical Findings Section)
Febrile nonhemolytic reaction and urticarial/allergic reaction are the two most common types of reactions that occur in blood product transfusions. Many institutions have a policy that provides for premedication with acetaminophen and diphenhydramine to avoid initiation of mild transfusion reactions, where appropriate.
IgA Deficient Transfusion Reaction—A Relatively Rare But Potentially Serious Reaction (Also Refer to the Critical Findings Section)
IgA is primarily involved in immune health maintenance of the mucosa that lines the gastrointestinal, genitourinary, and respiratory systems. IgA deficiency is the most common deficiency of the five main immunoglobulin classes (IgA, IgD, IgE, IgG, and IgM). Antibodies to IgA and other immunoglobulins are present in the plasma unless they are sourced from:
Factors That May Alter the Results of the Study
Other Considerations
RBC Component Compatibility
*If RBC units of exact match to the patient’s group and type are not available, a switch in ABO blood group is preferable to a change in Rh type. However, in extreme circumstances, Rh-positive blood can be issued to an Rh-negative recipient. It is very likely that the recipient will develop antibodies as the result of receiving Rh-positive red blood cells. Rh antibodies are highly immunogenic, and once the antibodies are developed, the recipient can receive only Rh-negative blood for subsequent red blood cell transfusion. | ||||||||||||||||||||||||||||||||||||||||||||||||||||
Are All Blood Components Tested for ABO Grouping, Rh Type, and Compatibility?
The short answer is yes—to ABO grouping and Rh type. The FDA requires that all blood component labels include the donor’s blood group and type. Compatible is not the same as identical or matched ABO group and Rh typed components. Compatibility testing for RBC products is always required; however, administration of identical or matched components is not always required; guidance regarding selection of mismatched components is clearly stated in the facility’s related policy and procedure (P&P) manual. Generally, compatible blood transfusion components of the same ABO group and Rh type as the patient are the first choice and routinely those choices are followed.
The decisions made to administer group and/or type components that are not identical comes down to product availability, how much product is expected to be transfused, and the urgency of the patient’s medical situation. It is not uncommon when responding to a traumatic injury to find that the patient’s blood group and type is unknown. In some cases, blood for transfusion must be released before group, type, and compatibility testing is completed—an emergency release is guided by specific P&Ps. In other situations, identical group and type components may not be available, as in the case of rare blood types, rare antibodies, or lack of inventory (e.g., platelets inventory can be a nightmare to manage; units have a 5-day shelf life). Choices of the safest mismatched component for transfusion are also based on the patient’s age (adult vs. pediatric) and gender/menopausal state (male and post menopausal female vs. premenopausal female). For example, transfused RBC components are always ABO compatible, but there are exceptions in the case of Rh typing as noted in the table above. Exceptions are often driven by the safest choice considering the situation and product availability. For example, in an emergency, if there is no ABO compatible Rh-negative unit available, an Rh-negative patient may be given a unit of Rh-positive RBCs—with the understanding that the patient will most likely develop Rh antibodies and can never be transfused with anything but Rh-negative blood in the future. This scenario would be more significant for an Rh-negative female of childbearing age since future pregnancies involving an Rh-positive fetus would become complicated by the presence of the mother’s Rh antibodies.
The main categories of blood components used for transfusion include RBCs, plasma (usually FFP), cryoprecipitate (cryo), and platelets. Each component has subcategories that speak to their specific method of collection, preparation, and preservation (to extend shelf life), e.g., plasmapheresis, leukoreduced RBCs, pooled platelets, RBCs with adenine saline. Examples of further processing of blood components include irradiation, leukocyte reduction, pathogen reduction technology, volume reduction, and washing.
Blood banks have a comprehensive collection of P&Ps to ensure safe procurement, testing, and administration of blood products for transfusion. Laboratories are regulated by the federal government and undergo periodic, rigorous inspections by agencies such as Centers for Medicare & Medicaid Services (CMS) and the Joint Commission; blood banks that procure blood and manufacture blood components for transfusion are also periodically inspected by the FDA. Some laboratories and blood banks also choose to earn certification by national and international organizations such as the AABB, COLA, and the College of American Pathologists. This level of regulatory oversight is important to note because choices of blood products may not always seem to make sense. Decisions regarding blood product administration carry a heavy burden of responsibility for everyone involved (e.g., requesting health-care providers, pathologists, nurses, laboratory technicians and technologists, unit secretaries, transporters).
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Potential Nursing Problems: Assessment & Nursing Diagnosis
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Before the Study: Planning and Implementation
Teaching the Patient What to Expect
Potential Nursing Actions
Make sure a written and informed consent has been signed prior to any transfusion blood products.
Safety Considerations
After the Study: Implementation & Evaluation Potential Nursing Actions
Avoiding Complications
Treatment Considerations
Cardiac Output
Fluid Volume
Gas Exchange
Injury, Risk
Safety Considerations
Clinical Judgement
Follow-Up and Desired Outcomes