The CLL Panel by FISH (Fluorescence in situ hybridization) is a specialized genetic test for Chronic Lymphocytic Leukemia (CLL), using fluorescent probes to detect specific chromosomal changes (deletions, duplications like 13q-, 17p-, trisomy 12) in blood or bone marrow cells, helping doctors diagnose, predict prognosis, guide treatment (chemo, immunotherapy), and monitor the disease’s response or progression, especially when routine tests are inconclusive