This is what we do.......... When more than one method can be used to perform testing in the Blood Bank, each method will be checked against each other at least twice a year for correlation of results. 3 patient samples for each different test method will be compared under actual testing conditions. Quality control data may be used for the comparison of results when the same manufacturer and lot number of reagents are being used. The following tests will be compared: ABO/Rh typings, antibody screens, direct antiglobulin test, immediate spin crossmatch, full crossmatch, and blood type confirmations. The methods that will be compared are automated gel testing, manual gel testing, and tube testing (LISS and PEG).