Cross-matching

Cross-matching
Cross-matching
Intervention
MeSH D001788

Cross-matching blood, in transfusion medicine, refers to the complex testing that is performed prior to a blood transfusion, to determine if the donor's blood is compatible with the blood of an intended recipient, or to identify matches for organ transplants. Cross-matching is usually performed only after other, less complex tests have not excluded compatibility. Blood compatibility has many aspects, and is determined not only by the blood types (O, A, B, AB), but also by blood factors, (Rh, Kell, etc.).

Cross-matching is done by a certified laboratory technologist, in a laboratory. It can be done electronically, with a computer database, or serologically. Simpler tests may be used to determine blood type (only), or to screen for antibodies (only). (indirect Coombs test).

Contents

Types of cross-matching

Electronic cross-matching

Electronic cross-matching is essentially a computer-assisted analysis of the data entered from testing done on the donor unit and blood samples drawn from intended recipient. This includes ABO/Rh typing of the unit and of the recipient, and an antibody screen of the recipient. Electronic cross-matching can only be used if a patient has a negative antibody screen, which means that they do not have any active red blood cell atypical antibodies, or they are below the detectable level of current testing methods. If all of the data entered is compatible, the computer will print a compatibility label stating that the unit is safe to transfuse.

Serological cross-matching

In serological cross-matching, red blood cells from the donor unit are tested against the serum of the patient in need of the blood transfusion. If the patient’s serum contains antibodies against the antigens present on the donor red blood cells, agglutination will occur. Agglutination is considered a positive reaction indicating that the donor unit is incompatible for that specific patient. If no agglutination occurs the unit is deemed compatible and is safe to transfuse.

Cross-matching falls into two categories:

  • Major Cross-match: Recipient serum is tested against donor packed cells to determine if the recipient has preformed antibodies against any antigens on the donor's cells. This is the required cross-match prior to release of a unit of packed cells.
  • Minor Cross-match: Recipient red cells are tested against donor serum to detect donor antibodies directed against a patient's antigens. This is no longer required. It is assumed that the small amount of donor serum and antibodies left in a unit of packed cells will be diluted in a recipient.

Emergencies

In the case of an emergency a physician, physician assistant, or nurse practitioner can request "uncross-matched blood", or donor units of blood that have not been cross-matched. It is thought that this lifesaving measure is of more benefit than any risk of an antibody-mediated transfusion reaction. In addition, the risk of a serious transfusion reaction can be minimized if the donor unit is both ABO-compatible and Rhesus (Rh)-compatible. Type O and Rh negative blood can be given if the recipient's blood group is not known, as may happen in an emergency. In an emergency, blood grouping can be done easily and quickly in 2 or 3 minutes in the laboratory on glass slides with appropriate reagents, by trained technical staff. This method depends on the presence or absence of agglutination, which can usually be visualized directly, although occasionally a light microscope may be needed. If laboratory services are not available, another system of deciding which type of blood to use in an emergency is the bedside card method of blood grouping, where a drop of the intended recipients' blood is added to dried reagents on a prepared card. This method may not be as reliable as laboratory methods, which are preferable.

External links

  • HealthAtoZ.com Blood typing and crossmatching
  • Nobelprize.org Interactive online game for blood typing and transfusion (Flash Player 5 required)

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Look at other dictionaries:

  • cross-matching — crossˈ matching noun • • • Main Entry: ↑cross …   Useful english dictionary

  • cross matching — cross′ match ing n. med the testing for compatibility of a donor s and a recipient s blood prior to transfusion, in which serum of each is mixed with red blood cells of the other and observed for hemagglutination …   From formal English to slang

  • cross matching — noun Etymology: cross (III) : the testing of the compatibility of the bloods of transfusion donor and recipient by mixing the serum of each with the red cells of the other to determine the absence of agglutinative reactions * * * Med. the testing …   Useful english dictionary

  • cross matching — Med. the testing for compatibility of a donor s and a recipient s blood prior to transfusion, in which serum of each is mixed with red blood cells of the other and observed for hemagglutination. Also, crossmatch /kraws mach , kros /. [1935 40] *… …   Universalium

  • cross-matching — 1. A test for incompatibility between donor and recipient blood, carried out prior to transfusion to avoid potentially lethal hemolytic reactions between the donor s red blood cells and antibodies in the recipient s plasma, or the reverse;… …   Medical dictionary

  • cross matching — crossmatching …   Medical dictionary

  • cross-match — /kraws mach , kros /, v.t. 1. to match (related items from two or more lists or groups). 2. Med. to subject (blood) to cross matching. [1925 30] * * * crossˈ match transitive verb To test (blood samples from a donor and a recipient) for… …   Useful english dictionary

  • cross-match — /kraws mach , kros /, v.t. 1. to match (related items from two or more lists or groups). 2. Med. to subject (blood) to cross matching. [1925 30] * * * …   Universalium

  • Cross Game — volume 1 cover as published by Shogakukan, showing Ko (left) and Wakaba クロスゲーム …   Wikipedia

  • cross-trading — ˈcross ˌtrading also crosstrading noun [uncountable] FINANCE when currency dealers in one country buy or sell the currency of a second country in exchange for the currency of a third country: • The dollar also benefited against the euro by… …   Financial and business terms

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