The CYP2D6 enzyme metabolizes ~25% of clinically used drugs. The CYP2D6 gene is a highly polymorphic gene, and specific genetic variants of CYP2D6 have been shown to be associated with different metabolism rates, but this is at present poorly documented. The interindividual differences make understanding an individual's CYP2D6 enzymatic activity vital for some medical treatments. We investigate the matching between predicted and directly measured phenotypes of CYP2D6 in a sample of healthy individuals from Addis Ababa, Ethiopia. To address the limitations of current sequencing approaches, we used PacBio technology, and we established an analysis workflow. Current results indicate a matching level of ~73% between the predicted and measured phenotypes, which suggests that besides genetic variations, environmental factors could also influence interindividual phenotype variation. Further investigations between populations living in different environments should be considered, a perspective that is now at hand with the established protocol in our study.