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Test Code NGFFPE (FFPE), NGSCS (Cytology Smear) OncoScreen- Extended RAS Assay

Specimen Type

FFPE or Cytology Smear


Blocks or slides

Preferred Volume


Offsite Collection Instructions

  • Formalin-fixed, paraffin embedded tissue: Total tumor area on slides = 0.1 cm2 total (include top and bottom H&E guide slides).
  • Paraffin block acceptable.

UCMC Collection Instructions

  • FFPE tissues: a pathologist will review the respective case upon receiving a requisition to select the appropriate block for testing. Slides will be recut and evaluated, tumor-rich areas are selected for testing.
  • Cytology smears: immediate on-site adequacy assessment is performed by a pathologist and tumor-rich areas are selected for testing.


Monday – Friday, 8:00am – 5:00pm

Turnaround Time

8-10 business days

STAT Availability

Not Available

Test Methodology

KRAS, HRAS and NRAS genes are part of the OncoScreen ST2.0 NGS panel. The OncoScreen procedure is performed and data for the 3 genes only is analyzed.
The OncoScreen test is based on the Ion AmpliSeq Cancer Hotspot Panel (IACHP) v2 (Life Technologies). After DNA is isolated and its quality and quantity determined, a single multiplexed PCR is performed using a single reaction containing the 207 Ion AmpliSeq Cancer Hotspot primer pairs. It is then cleaned up using Ampure XP beads and a library is constructed using KAPA HTP Library Preparation Kit and Illumina compatible adapters. Through the library construction, adapter oligonucleotides containing unique patient-specific “barcode” indexes and P5/P7 sequences are ligated onto the amplicon PCR products to make an Illumina compatible sequencing library.All DNA samples for a given run are processed in duplicate and in parallel, and then following a library quantitation, samples with different bar-code sequences are pooled and sequenced in a 2 × 152 bp MiSeq run.

Additional Information

  • Reporting: Mutations with known or possible pathogenic or clinical significance are reported. Variants of unknown significance are reported as such.

STAT Turnaround Time


Reference Range

Interpretive report will be provided.

Test Limitations

  • This test will not detect mutations outside the targeted genomic regions.
  • Copy number alterations and translocations will not be detected. This test is not intended to detect minimal residual disease.
  • Assay sensitivity is 5% mutant allele frequency (MAF), thus false-negative results may occur when there is a lower mutant allele burden.
  • Variants present at oligonucleotide binding sites may negatively interfere with hybridization (as with any PCR-based assay), potentially resulting in underestimation of a particular allele frequency.

Test Includes

This is a next-generation Sequencing panel that tests hot spot regions of 3 genes that are part of the Solid Tumor OncoScreen ST 2.0 panel. The tested genes are: KRAS (exons 2, 3, and 4), NRAS (Exons 2, 3, and 4) and HRAS (Exons 2 and 3).