A rubella titer showing a greatly increased level over a previous reading indicates what?

A rubella titer showing a greatly increased level over a previous reading indicates what?

• A. Recent infection
• B. Immunity
• C. Susceptible
• D. No infection

Answer: (A)

Rising rubella antibody levels between tests show the body is actively responding to a recent exposure. When the titer increases markedly from a previous reading, it indicates seroconversion or an acute/recent infection, because the immune system is mounting a stronger antibody response now. Immunity from prior infection or vaccination would usually be reflected by a stable or high baseline IgG without a rapid rise. A significant rise, often a fourfold or greater increase between paired samples, is the classic sign of a recent rubella infection.

Rising rubella antibody levels between tests show the body is actively responding to a recent exposure. When the titer increases markedly from a previous reading, it indicates seroconversion or an acute/recent infection, because the immune system is mounting a stronger antibody response now. Immunity from prior infection or vaccination would usually be reflected by a stable or high baseline IgG without a rapid rise. A significant rise, often a fourfold or greater increase between paired samples, is the classic sign of a recent rubella infection.