Reference Range
The upper normal level of eNO in different studies ranges from 20 to 30 parts per billion. However, several major features influence the reference values. Men have higher eNO values than women. Smoking notoriously lowers eNO values, and even former smoking status can influence results. The levels are higher in people with an atopic constitution (a tendency towards allergies). The fraction of eNO is also flow-dependent (higher at lower flow rates and vice versa), so measurements are normally measured at 50 ml/s. Age or height could also considerably confound eNO values in children. The magnitude of these effects lies in the order of 10%, so even single cut-off values might be useful.
Read more about this topic: Exhaled Nitric Oxide
Famous quotes containing the words reference and/or range:
“In sum, all actions and habits are to be esteemed good or evil by their causes and usefulness in reference to the commonwealth, and not by their mediocrity, nor by their being commended. For several men praise several customs, and, contrarily, what one calls vice, another calls virtue, as their present affections lead them.”
—Thomas Hobbes (1579–1688)
“[F]or as Socrates says that a wise man is a citizen of the world, so I thought that a wise woman was equally at liberty to range through every station or degree of men, to fix her choice wherever she pleased.”
—Sarah Fielding (1710–1768)