The XL ATM/11cen probe is a qualitative, non-automated test for the detection of deletions of the ATM gene region at 11q22.3 by fluorescence in situ hybridization (FISH). The product is intended as a diagnostic aid and assists in disease monitoring. The test population consists of patients with confirmed or suspected chronic lymphocytic leukemia (CLL), T-cell prolymphocytic leukemia (T-PLL) and non-Hodgkin-lymphomas (NHL). Hybridization is to be performed on methanol/acetic-acid fixed cells derived from bone marrow or peripheral blood for CLL and T-PLL and on methanol/acetic-acid fixed cells derived from involved lymph node, involved bone marrow or other involved tissue for NHL.