UGT1A1*80 is in very high linkage disequilibrium with *28 and *37. In the rare event that *80 is detected but *28 and *37 are not, there are not enough clinical data to predict metabolizer status with certainty. However, if only *80 is interrogated and the patient is heterozygous or homozygous for *80, an intermediate or poor metabolizer phenotype may be inferred, respectively.