The range of viral load is so wide that results are often given as results from a logarithmic (log) scale.
This is an easier way to deal with very large and very small numbers at the same time. Less than 50 copies/mL for most people on treatment is 1.7 logs. In very early infection, a viral load of 10 million copies is 7.0 logs.
Log value is a measurement used to describe HIV and expresses the viral load values as a power of ten (written log10). The scale is used because large changes can only be captured on graphs or diagrams by using a log scale. This turns large numbers of copies/mL into ‘manageable’ figures.
Table: HIV RNA viral load log value–number conversion