Naso-pharyngeal aspirate or other respiratory secretion must contain intact respiratory epithelium to be deemed adequate for examination. Inadequate specimen collection and too few cells on the slide may lead to failure of direct smears to detect respiratory viruses. Smears contaminated with RBCs can be misinterpreted due to RBC autofluorescence. Smears with less than 25 cells often prove inconclusive and will be reported as inadequate. Viral respiratory tract infections are the most common diseases affecting humans throughout the world.
Viruses are the fourth leading cause of hospital- treated pneumonia in otherwise healthy adults.
Infants, the elderly, and individuals with compromised cardiac, pulmonary, or immune systems are at greatest risk of serious complications from these viruses. Culture backup for negative results is strongly recommended. Its performance characteristics were determined by ARUP Laboratories. Virology , 3rd ed. Davis, et al.