出典(authority):フリー百科事典『ウィキペディア(Wikipedia)』「2014/08/02 03:48:18」(JST)
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Cross-matching | |
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Intervention | |
MeSH | D001788 |
Cross-matching (or crossmatching) blood, in transfusion medicine, refers to the testing that is performed prior to a blood transfusion in order 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 confirmed 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).
This is the most comprehensive form of cross-matching, making it the safest form, but it is also the most expensive and time-consuming. It involves serological body-temperature tests and can take around an hour.
Immediate-spin cross-matching (ISCM) is an abbreviated (faster, less expensive, less sensitive) form of cross-matching that is conditionally appropriate as either preliminary to, or in place of, full cross-matching. It is an immediate, room-temperature serological test, taking only several minutes.
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.
Cross-matching falls into two categories:
As the complete cross-matching process requires approximately 1 hour to be done, it's not always used in emergencies.
In the case of an emergency, a type-specific blood ("uncross-matched blood") can be requested. It is thought that this lifesaving measure is of more benefit than any risk of an antibody-mediated transfusion reaction. This type of blood has less risk of a serious transfusion reaction because it 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.
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リンク元 | 「クロスマッチ」 |
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