CFTR and infection: Four strata distributed subjects into roughly equal size groups for each infecting organism (FEV1BeforeInfx less than the 50th %ile, 50-74.9th %ile, 75-89.9th %ile and greater than the 90th %ile) and revealed that the effect of CFTR genotype upon risk of infection differed depending upon lung function and the organism involved (TABLE 5).