North American pretransfusion testing practices, 2001-2004: results from the College of American Pathologists...

Pretransfusion testing of whole blood and red blood cell recipients is regulated by the federal government under the authority of the Clinical Laboratory Improvement Amendments of 1988. Regulated tests include determination of ABO group, Rh D type, antibody detection, antibody identification, and crossmatching. A wide variety of methods and reagents are available for these regulated tests. During 2001-2004, the College of American Pathologists (CAP) Interlaboratory Comparison Program (Proficiency Testing) J-Survey collected data from more than 4000 laboratories regarding their pretransfusion testing practices. Those data are presented in this report.

To assess current testing practices for ABO grouping, Rh D typing, antibody detection, and crossmatching in North America.

Data collected for the CAP Interlaboratory Comparison Program (Proficiency Testing) J-Survey were analyzed for trends in laboratory testing practice during 2001- 2004. The data were grouped for analysis by peer group (testing method used) for ABO grouping, Rh D typing, antibody detection, and crossmatching and then analyzed. SETTING, PATIENTS, OR OTHER PARTICIPANTS: Subscribers to the CAP Interlaboratory Comparison Program Transfusion Medicine J-Series.

The most common testing schemes used in North America during 2001-2004 are as follows: ABO grouping (most laboratories perform tube testing: 97.6% in 2000 and 91.1% in 2004); Rh D typing (most laboratories perform tube testing: 97.7% in 2001 and 91.1% in 2004); antibody detection (most laboratories perform tube testing: 69.7% in 2001 and 55% in 2004, most frequently with the low ionic strength solution anti-human globulin [AHG] method, 48.3% in 2001 and 39.9% in 2004; as of 2004 slightly more laboratories use the gel AHG method [42%] than the low ionic strength solution AHG tube method); crossmatching for alloimmunized patients (most laboratories perform tube testing using a low ionic strength solution AHG method; 55.8% in 2001 and 47.6% in 2004); and crossmatching for nonalloimmunized patients (tube testing using an immediate spin method; 42% in 2001 and 40.4% in 2004).

Most North American laboratories currently favor tube methods when performing ABO grouping, Rh typing, antibody screening, and crossmatching. However, there has been a significant increase in the use of gel-based methods in recent years, especially for antibody detection and crossmatching. Data collection and data analysis of CAP Interlaboratory Comparison Program Survey results allow for assessment of laboratory proficiency and provide insights into current North American practice trends in pretransfusion compatibility testing.