Safety of a liberal policy for extended-date preadmission testing samples

Regulations governing pretransfusion testing allow specimen expiration to be extended past 3 days before the transfusion if a patient has not been transfused or pregnant in the preceding 3 months. Our hospital allows extension of the expiration of a presurgical specimen to 28 days if 1) the patient has neither been transfused nor pregnant in the past 3 months, 2) the patient does not have an antibody history, and 3) the current antibody screen (ABSC) is negative. Patients not meeting Criteria 2 and 3 are required to have specimens redrawn on the day of surgery (DOS). We evaluated the necessity of this policy.

From October 2009 to September 2010, there were 132 patients who did not meet the above criteria for specimen extension. Equivalent tests were performed on preadmission testing (PAT) and DOS specimens, and the results were compared.

The majority (113, 86%) of the samples redrawn on the DOS showed no change in antibody serology upon reinvestigation. Of the remaining patients, DOS specimens did not identify any new antibodies or change in blood product choices.

Of the PAT specimens rejected for antibody history or positive ABSC, none had new significant serologic findings on DOS. Based on these results, requiring a repeat specimen on the DOS may not be clinically necessary. Our facility changed the PAT policy to extend specimen acceptability to patients with red blood cell antibody history or positive ABSC at time of PAT. A 6-month follow-up period showed that this practice is safe.