Qualitative hematological toxicity variables, including thrombocytopenia, leukopenia, neutropenia, lymphocytopenia, and anemia, were assessed at five different time points for their correlation with various alleles of the CYP2C19, ALDH3A1, SLC22A16, and ABCB1 genes. The gene discussed is ABCB1; the disease is Thrombocytopenia.