Management of pre-admit surgery patients known to have previously identified antibodies

A colleague from the Pacific Northwest would like to know how others handle pre-admit surgery patients who are known to have previously identified antibodies. Their institution currently has a 14 day limit on how far in advance of surgery a pretransfusion sample may be drawn, provided a patient has no history of transfusion or pregnancy in the preceding 3 months. This applies to patients with and without a history of alloantibodies. The pretransfusion samples are routinely tested for ABO/Rh and unexpected antibodies within 48 hours of sample collection, however, crossmatches are generally not performed until the day before surgery is scheduled, so as to not tie up inventory of blood products for long periods of time. The inquiring colleague's institution is considering changing policy to require that a patient with a previously identified antibody be drawn within 2 days of their scheduled surgery date, even if the patient has not been pregnant or transfused in the preceding three months. This is based on a concern of drawing a patient up to 14 days before their surgery, performing the antibody screen within 48 hours of collecting the sample, yet waiting for up to 13 days before performing an antiglobulin crossmatch.

• How are others approaching pre-surgery compatibility testing of known alloimmunized patients?
• Do colleagues accept pretransfusion samples from such patients well in advance of surgery for pre-admit testing, or do colleagues require that a specimen be drawn upon the surgical admission, or within a 3-day period immediately preceding the surgery, even though the patient may not have been transfused or pregnant within the last 3 months?

Please share your policies and the basis (scientific, reagent manufacturer's instructional insert, etc.) upon which they are formulated.

The following responses were received.

ADDENDA Jan. 14, 2004

1. A transfusion medicine physician in Los Angeles would be opposed to discouraging submission of pretransfusion samples from alloimmunized patients in the final two days before a scheduled surgery, as suggested by the colleague from the Pacific Northwest. Rather, this physician is of the opinion that it would be preferable to obtain a pretransfusion specimen from a patient known to be alloimmunized as far in advance of surgery as possible to give the hospital transfusion service as much time as possible to find RBC units, in the event that the patient needs blood products from rare donors.
   
   
2. A colleague in Ontario, Canada reports that at her institution, if a patient has not been transfused or pregnant within the past three months, they would draw preadmission specimens up to 30 days prior to the scheduled surgery and crossmatch any RBC units the evening before the scheduled surgical procedure. This approach would be employed regardless of whether they are known to be alloimmunized. The 30-day outdate was chosen to correspond with acceptable guidelines for other preadmission tests, such a hemoglobin. All preadmission blood specimens are drawn at the same time. In their opinion, the patient's antibody status would not be expected to change without additional exposure to red cells. However, if the patient has been transfused within the past three months, they would require a new specimen to be drawn within 48 hours of the scheduled surgery.

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