CYP2B6*13 (c.415A>G, p.K139E; c.516G>T, p.Q172H/splice defect; c.785A>G, p.K262R) - No function: CYP2B6*13 is assigned no function. CYP2B6*13 contains the same variants as CYP2B6*6, which is assigned decreased function, and CYP2B6*8 which is assigned no function. Most in vitro studies including those using cDNA expression systems (15190123, 20517174, 30201214) and human liver microsomes (17559344) found that CYP2B6*13 has no enzyme activity; only one in vitro study using a cDNA expression system showed residual activity for artemether metabolism compared to the *1 reference. This discrepancy is probably due to differences in the in vitro expression systems and substrates used. Therefore, consensus among experts was no function based on limited evidence.