EXISTING PROBLEMS IN THE TESTING FOR INFECTIOUS-DISEASES

Current methods for testing donated blood for presence of infectious v iral agents in the USA differ from those used in other countries becau se of the USA Food and Drug Administration's (FDA) control which inhib its rapid introduction of testing methods or improvements. Delays in F DA approval may occur because of concerns about methodology or the sta te of knowledge about the disease it is intended to detect as wellas d ue to variability between manufacturers. Despite strict FDA control, t esting problems continue to occur in the USA. No approved method detec ts infectious agents during the ''window period,'' and variations in d etection, i.e., false positives and false negatives (even with confirm atory testing), continue to occur. The effect of physical and chemical changes (e.g., various anticoagulants) on samples has not been thorou ghly evaluated. Test performance problems include lapses in sample ide ntification, failure to use routine laboratory controls, improper calc ulation and reporting of results, improper acceptance of test runs and failure to properly detect and retest samples when carryover from ver y reactive samples occurs. For these reasons, transfusion-related dise ase transmission continues to occur. The current USA emphasis on good manufacturing practices should provide continuous improvements.