Titer: The concentration of a substance in a fluid, such as the concentration of an antibody in blood. The titer reflects the amount of the substance in the fluid. Sometimes also spelled titre. QUESTION Allergies can best be described as: See Answer From Allergies Resources Seasonal Impact of RSVLearn How to Treat Chronic HivesBreaking Out in Hives When You're Nervous? Featured Centers What Are the Best PsA Treatments for You?Understanding Biologics 10 Things People With Depression Wish You Knew Health Solutions From Our Sponsors Shot-Free MS Treatment Your Child and COVID-19