Quality control in immunophenotyping: U.S. efforts to establish common methodology and their impact. American Society for Histocompatibility and Immunogenetics.

Several organizations in the United States have recently been involved in the quality assurance of immunophenotyping using flow cytometry. These activities include publication of guidelines for immunophenotyping, particularly in human immunodeficiency virus infection, performance evaluation and proficiency testing programs, and training and continuing education programs. Through questionnaires and results from performance evaluation programs, variability in test results has been decreasing the last few years, and more laboratories are beginning to use the same specimen processing and data analysis procedures.