Runyon classification
The Timpe and Runyon classification of nontuberculous mycobacteria is based on the rate of growth, production of yellow pigment and whether this pigment was produced in the dark or only after exposure to light.
It was introduced by Ernest Runyon in 1959.
On these bases, the nontuberculous mycobacteria are divided into four groups. The first three groups are classified as "Slowly growing Mycobacteria" and the fourth group as "Rapid Growers".