Comparison of indirect immunofluorescence and membrane fluorescence assays for the differentiation of antibodies to human immunodeficiency virus types 1 and 2

Microarray detection of human parainfluenzavirus 4 infection associated with respiratory failure in an immunocompetent adult

A pan-viral DNA microarray, the Virochip (University of California, San Francisco), was used to detect human parainfluenzavirus 4 (HPIV-4) infection in an immunocompetent adult presenting with a life-threatening acute respiratory illness. The virus was identified in an endotracheal aspirate specimen, and the microarray results were confirmed by specific polymerase chain reaction and serological analysis for HPIV-4. Conventional clinical laboratory testing using an extensive panel of microbiological tests failed to yield a diagnosis. This case suggests that the potential severity of disease caused by HPIV-4 in adults may be greater than previously appreciated and illustrates the clinical utility of a microarray for broad-based viral pathogen screening.

Existing problems in the testing for infectious diseases

Current methods for testing donated blood for presence of infectious viral agents in the USA differ from those used in other countries because of the USA Food and Drug Administration's (FDA) control which inhibits rapid introduction of testing methods or improvements. Delays in FDA approval may occur because of concerns about methodology or the state of knowledge about the disease it is intended to detect as well as due to variability between manufacturers. Despite strict FDA control, testing problems continue to occur in the USA. No approved method detects infectious agents during the "window period," and variations in detection, i.e., false positives and false negatives (even with confirmatory testing), continue to occur. The effect of physical and chemical changes (e.g., various anticoagulants) on samples has not been thoroughly evaluated. Test performance problems include lapses in sample identification, failure to use routine laboratory controls, improper calculation and reporting of results, improper acceptance of test runs and failure to properly detect and retest samples when carryover from very reactive samples occurs. For these reasons, transfusion-related disease transmission continues to occur. The current USA emphasis on good manufacturing practices should provide continuous improvements.