This diagnostic package, based on immunohistochemistry, includes the examination of a range of markers to confirm the B-cell origin of lymphoblastic neoplasms. The package primarily includes the examination of CD79a, an early and persistent cytoplasmic component of the B-cell receptor (BCR) complex, making it a highly sensitive and specific marker for B-cell origin even in very early stages. It also includes essential complementary markers: CD20 (a mature membrane marker for B cells), PAX5 (a nuclear transcription factor specific to B cells), and T-cell markers such as CD3 to rule out a T-cell origin. The package aims to confirm the initial diagnosis of B-cell neoplasms and provide a solid foundation for subsequent subclassification.