For most children, the National Heart, Lung, and Blood Institute recommends one cholesterol screening test between the ages of 9 and 11, and another cholesterol screening test between the ages of 17 and 21.
Wiktionary (0.00 / 0 votes) Rate this definition: fixation (Noun). The act of fixing, or the state of being fixed or fixated. fixation (Noun). The act of uniting chemically with a solid substance or in a solid form; reduction to a non-volatile condition; -- said of gaseous elements. fixation (Noun). The act or process of ceasing to be fluid and becoming firm.
Complement fixation refers to a reaction in which an antigen binds with an antibody, forming a combination that causes complement (a complex group of blood proteins) to become fixed at the same site. Detection of this complement fixation reaction leads to identification of the original antigen.