BCR/ABL TRANSLOCATION ASSAY By FISH

The FISH (fluorescence in situ hybridization) test detects the BCR‑ABL fusion (Philadelphia chromosome) by using fluorescent probes that bind BCR and ABL genes in blood or bone‑marrow cells. A merged signal shows the t(9;22) translocation. FISH helps diagnose chronic myeloid leukemia and some acute leukemias, quantify affected cells, detect cryptic rearrangements, and monitor treatment response and residual disease.

FISH (fluorescence in situ hybridization) for CML uses fluorescent DNA probes to detect the BCR‑ABL1 gene fusion or Philadelphia chromosome in blood or bone marrow cells. It binds specific DNA sequences in interphase or metaphase cells, enabling rapid diagnosis and monitoring of residual disease and treatment response, especially when conventional karyotyping is unavailable or slower.

Testing for BCR‑ABL uses cytogenetics (karyotyping) to detect the Philadelphia chromosome, fluorescence in situ hybridization (FISH) to localize the fusion gene, and reverse transcription–polymerase chain reaction (RT‑PCR) — especially quantitative real‑time PCR — to detect and measure BCR‑ABL transcripts in blood or bone marrow. PCR also identifies transcript variants and is used for treatment monitoring on an international scale.

FISH uses fluorescent probes to visualize specific DNA/RNA sequences directly in cells or tissue, showing spatial location, gene fusions, or chromosomal changes at single‑cell resolution. RT‑PCR converts RNA to cDNA then amplifies it to detect and quantify transcripts or pathogens; it's highly sensitive and quantitative but lacks spatial information and usually analyzes bulk samples. FISH is cytogenetic/spatial; RT‑PCR is molecular/quantitative.

A positive fecal immunochemical (FIT) test means blood was detected in your stool but doesn’t confirm cancer. It requires prompt follow‑up—usually a referral for colonoscopy—to find the cause (polyps, cancer, hemorrhoids, inflammation or ulcers). Contact your GP or screening service promptly; urgent investigation is recommended. If you have heavy bleeding, severe pain, weight loss or changed bowel habits, seek immediate care.

In India, BCR‑ABL testing costs vary by test type and lab. Quantitative real‑time PCR (qPCR) commonly runs about ₹2,500–₹8,000 per test, while simpler qualitative PCR options may be ₹800–₹3,000. Accredited reference laboratories or IS‑standardized tests tend to be pricier. Costs depend on location, urgency, and lab accreditation—confirm exact pricing and reporting format (international scale) with your local diagnostic center.