Complex sentence: Viral load is a measure of the severity of a viral infection, and can be calculated by estimating the amount of virus in an involved body fluid, for example, it can be given in RNA copies per milliliter of blood plasma.
Split into simpler sentences: Viral load is a measure of the severity of a viral infection, and can be calculated by estimating the amount of virus in an involved body fluid. For example, it can be given in RNA copies per milliliter of blood plasma.