Overview: FISH inv16 CBFB Panel
Introduction: The FISH inv16 CBFB Panel is a diagnostic tool designed to detect inv(16) in leukemia using whole blood or bone marrow samples. In India, inv(16)(p13q22) or t(16;16) occurs in ~5-8 percent of acute myeloid leukemia (AML), particularly M4Eo subtype, associated with favorable prognosis and high cure rates with standard chemotherapy. High morbidity from under-testing in rural/low-SES AML patients, limited FISH labs, delayed risk-adapted therapy leading to overtreatment or relapse. Per cytogenetics practices aligned with ICMR and Indian Society of Hematology guidelines, the test employs FISH for CBFB rearrangement over 1-2 days with high sensitivity/specificity, valuable for rapid diagnosis and favorable-risk classification in AML. This diagnostic falls under genetic cancer screening and targets AML patients (especially with eosinophilia or M4/M5 morphology), addressing accurate detection to guide consolidation chemotherapy and avoid unnecessary transplant. With elevated morbidity due to under-testing, the test supports public health efforts by enabling precise molecular subtyping and improving survival. Its blood/bone marrow-based approach ensures reliable inversion detection.
Other Names: FISH inv16 Pnl.
FDA Status: FDA approved, CLIA certified for cytogenetics/oncology, compliant with 2025 standards.
Historical Milestone: inv(16) FISH favorable marker; in India, used in AML protocols.
Purpose: The test detects 2 parameters including inv(16) CBFB to guide leukemia genetic assessment, identify favorable-risk feature, inform therapy.
Test Parameters: 1. inv(16) CBFB, 2. Chromosomal Rearrangement.
Pretest Condition: No fasting required; patients should have confirmed AML.
Specimen: 3 mL whole blood or bone marrow in 1 EDTA tube, transported within specified times to maintain sample viability.
Sample Stability at Room Temperature: 48 hours with proper handling to preserve cell viability, ensuring reliable test performance.
Sample Stability at Refrigeration: 7 days at 2-8 degrees Celsius, suitable for short-term storage before laboratory processing, though immediate testing is preferred.
Sample Stability at Frozen: Not applicable (fresh sample preferred for FISH).
Medical History: Patients should provide details on AML subtype, eosinophilia, prior therapy.
Consent: Written informed consent is required, detailing the test's purpose, potential risks of undetected favorable abnormality including overtreatment, benefits of detection, and minimal discomfort from blood/bone marrow draw.
Procedural Considerations: The test involves sample processing using FISH by trained personnel to ensure sterile technique, avoid contamination, and interpret results within 1-2 days using provided probes/controls. Laboratories must maintain a controlled environment, adhere to quality assurance protocols.
Factors Affecting Result Accuracy: Delays beyond stability periods, improper storage conditions, or low blast count can affect results. Correlation with clinical evaluation or additional testing is recommended to confirm findings.
Clinical Significance: Positive inv(16) indicates favorable AML prognosis, necessitating specialist input. Negative may require follow-up.
Specialist Consultation: Hematologists/oncologists should be consulted for management.
Additional Supporting Tests: Karyotype, NGS for confirmation.
Test Limitations: Detects inversion only; comprehensive approach required.
References: Indian Journal of Hematology 2024, AML Studies India 2023.
