Effective September 30, 2026, the 1p/19q Deletion by FISH assay will be discontinued.
 

Recommended Alternative

To assess for 1p/19q co-deletion, laboratories should order Cytogenetics, Chromosomal Microarray Analysis, FFPE Tissue (order code: CGAPT).

Test details and ordering information

 

Rationale for the Change

Multiple studies have shown that assessment of 1p/19q status by fluorescence in situ hybridization (FISH) may produce inaccurate results. Partial deletions of 1p and/or 19q can affect the regions targeted by FISH probes, potentially making them appear to be whole-arm deletions. For additional information, see PMID: 29600313 and 35233774.

 

Chromosomal microarray analysis provides a genome-wide assessment of copy-number variants and can more accurately distinguish whole-arm deletions from partial deletions. It also evaluates other copy-number variants relevant to central nervous system tumors, including:

• Chromosome 7 gain/chromosome 10 loss (+7/−10)
• EGFR amplification
• CDKN2A/B deletion