Detection Windows The window to detect the presence of a particular drug in a personâs urine is highly dependent on multiple factors, such as: Hydration-More dilute urine from high fluid intake may cause dilution of drug and therefore a negative result due to levels present but below the cutoff.
Alcohol flush reaction. Alcohol flush reaction is a condition in which an individual develops flushes or blotches associated with erythema on the face, neck, shoulders, and in some cases, the entire body after consuming alcoholic beverages.
Definition of flush. 1 :  a sudden flow (as of water); also : a rinsing or cleansing with or as if with a flush of water. 2a : a sudden increase or expansion; especially : sudden and usually abundant new plant growth the spring flush of grassb : a surge of emotion felt a flush of anger at the insult.