Once upon a time (in Bloodland) all donor RBC were crossmatched by IAT, even if the antibody screen was negative. In addition, for many types of surgery a high percentage of the donor blood that was crossmatched and held for patients was never transfused. This was wasteful of both the available donor blood and the blood bank technologist's time.
Fortunately, since about 1980 or so, it has become routine practice in most transfusion services for physicians to order a "type and screen" for patients who will probably not require blood transfusion during surgery. The type and screen consists of doing an ABO, Rh(D) type and antibody screen for unexpected antibodies on the patient. Providing that the antibody screen is negative, donor blood is not crossmatched and reserved for the patient. Once the type and screen is done, if blood is unexpectedly required during surgery, it can be quickly crossmatched (preferably by an IS or electronic crossmatch; or by an IAT crossmatch if that is the laboratory policy) because the blood bank has a record of patient ABO and Rh types , as well as the negative antibody screen.
To a large extent today, the use of the electronic crossmatch (or the IS crossmatch at RT ) has made the type and screen redundant. For patients without unexpected antibodies, blood can easily and rapidly be issued by using the computer to confirm ABO compatibility.
The type and screen offers several advantages over the older practice of crossmatching and reserving specific donor units for patients:
Better use of donor blood, as it is not tied up by being
crossmatched and held for patients who probably will not
need it.
More efficient service for patients, as blood bank personnel are not tied up crossmatching needlessly or removing tags from unused products but rather are available for more useful
purposes.
Potential for a more economic transfusion service due to decreased blood inventory requirements, decreased reagents, and more efficient use of technologist time.
The type and screen, in which specific donors are not crossmatched for patients, can be used in only particular circumstances:
It is indicated only for patients undergoing surgery in
which blood transfusion is unlikely to be required.
The antibody screen must be sensitive and reliable
or the patient's well-being can be put in jeopardy,
e.g., if clinically significant antibodies go undetected
in the type and screen, they will not be detected by an
IS or electronic crossmatch.
If an unexpected antibody is detected during the type
and screen, it is identified and donor blood must be
antigen typed and crossmatched (by tube IAT) so
that it will be available if required during
surgery.
Typically, a type and screen protocol includes provisions for a maximum surgical blood order schedule (MSBOS).
 Information Systems
| Type & Screen | MSBOS
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