Human leukocyte antigen (HLA) is located in the chromosome 6, which is present in almost all nucleated cells. The HLA system includes a complex array of genes, which controls the immune response through recognition of self and non-self antigens, which can lead to graft rejection. HLA typing, also known as tissue typing, is required majorly to examine graft rejection due to organ, tissue, blood cell, and bone marrow transplantation. Through this testing, bone marrow and blood cell transplantation complications can be minimized, which can increase the survival rate of the organ recipient.