BACKGROUND: The Philadelphia chromosome (Ph) represented a finding of chronic myeloid leukemia (CML) in most cases which formed from t (9
22) (q34
q11) resulting in the Breakpoint cluster region-Abelson tyrosine-protein kinase1 (BCR-ABL1) fusion gene. Assuming CCE's inaccuracies in diagnosing CML and FISH's limitations with low BCR-ABL1 percentages, a Predicted-FISH (Pred-FISH) was developed. This model predicts treatment response during follow-up by integrating qRT-PCR results, White Blood Cell (WBC) counts, and Cytogenetic Response data. METHODS: Quantitative Real-Time Polymerase Chain Reaction Analysis (qRT-PCR), fluorescence in situ hybridization (FISH), and Conventional Cytogenetic Examination (CCE or Karyotyping) have been used in the detection and follow-up of CML patients. The study included 110 individuals, divided into three groups: 31.82% (35 individuals) were newly diagnosed CML patients, another 22.73% (25 individuals) were healthy control samples, and the remaining 45.45% (50 individuals) were previously diagnosed CML patients. RESULTS: Include BCR-ABL1 fusion gene levels detected by qRT-PCR, Ph chromosome presence t (9
22) (q34
q11) observed by CCE, and WBC counts. The FISH test, used to confirm disease in new patients before treatment, was compared to CCE results due to its insensitivity in certain conditions. Data from CCE, FISH, qRT-PCR, and WBC for newly diagnosed patients provided a standard for evaluating the Predicted-FISH. CONCLUSION: The FISH technique excels in disease detection with over 98% accuracy and high sensitivity. QRT-PCR is effective for monitoring CML and BCR-ABL1 gene levels, indicating MMR and DMR. CCE, while useful for posttreatment monitoring, is less accurate in measuring treatment response over time.