88271

Molecular cytogenetics; in situ hybridization (ISH), fluorescence, each probe

CPT code 88271 describes the technical and professional components for the performance and interpretation of fluorescence in situ hybridization (FISH) using a single, individual fluorescent probe. FISH is a molecular cytogenetic technique that employs fluorescently labeled DNA probes to identify and localize specific DNA sequences on chromosomes or within interphase nuclei. This technique is utilized for the detection of chromosomal abnormalities, gene rearrangements, copy number variations, and aneuploidies in various clinical contexts, including cancer diagnosis and prognosis, prenatal screening, and the diagnosis of constitutional genetic disorders.

Clinical Indications

  • Detection of specific gene amplifications (e.g., HER2 in breast cancer, MYCN in neuroblastoma).
  • Identification of specific chromosomal translocations in hematologic malignancies and solid tumors (e.g., BCR-ABL1 in CML, PML-RARA in APL, ALK rearrangements in lung cancer).
  • Diagnosis of microdeletion or microduplication syndromes (e.g., DiGeorge syndrome, Williams syndrome, Prader-Willi/Angelman syndromes) using locus-specific probes.
  • Rapid detection or confirmation of common aneuploidies (e.g., Trisomy 13, 18, 21, sex chromosome aneuploidies) in prenatal or postnatal settings.
  • Assessment of minimal residual disease (MRD) in certain malignancies.
  • Characterization of complex chromosomal rearrangements when a single specific locus is targeted.

Procedure Steps

  1. Specimen collection and preparation, which may include cell culture (for metaphase FISH), fixation, and preparation of microscopic slides from blood, bone marrow, amniotic fluid, chorionic villus samples, or tissue biopsies.
  2. Denaturation of target DNA on the slide and the fluorescently labeled DNA probe to render them single-stranded.
  3. Hybridization of the single-stranded probe to its complementary target DNA sequence on the chromosomes or within interphase nuclei.
  4. Washing steps to remove non-specifically bound probes, ensuring specificity of signal detection.
  5. Counterstaining of the nuclei (e.g., with DAPI) to visualize the entire chromosome or nuclear structure.
  6. Microscopic analysis using a fluorescence microscope to visualize and interpret the fluorescent signals, documenting the presence, absence, or altered location of the target sequences.
  7. Image acquisition, analysis, and generation of a comprehensive diagnostic report.

Coding Guidelines

  • CPT code 88271 is used for the performance and interpretation of FISH utilizing a single, discrete fluorescent probe.
  • This code includes both the technical and professional components of the service.
  • When performing FISH with a panel of multiple probes (e.g., 3-5 probes, 6-9 probes, or 10-30 probes), use the appropriate panel codes (88273, 88274, or 88275, respectively) instead of reporting multiple units of 88271.
  • If a specific, additional individual probe is performed and analyzed outside of a defined panel (e.g., to further characterize a finding or rule out an additional specific aberration), 88271 may be reported for that additional probe.
  • Clinical documentation must clearly specify the exact probe(s) utilized, the specimen type, the clinical indication for the test, and the detailed results of the FISH analysis.
  • Do not report 88271 in conjunction with 88272 (bright field ISH, each probe) for the same probe target on the same specimen.

Associated ICD-10 Codes