EGFR Hotspot PCR Analysis Assay
Test Mnemonic
EGFRID
CPT Codes
- 81235 - QTY (1)
Aliases
- EGFR
- EGFRGN
Performing Laboratory
Cleveland Clinic Laboratories
Specimen Requirements
| Volume | Type | Container | Collect Temperature | Transport Temperature | Special Instructions |
|---|---|---|---|---|---|
| 10 mm square | Block, Formalin fixed paraffin | Formalin-fixed, paraffin-embedded block | Ambient | Ambient | Formalin-fixed paraffin-embedded tissue slides. Transport and store slides at ambient temperature. Three unstained sections FFPE tissue on charged, unbaked slides or scrolls, plus one H&E stained section with best tumor area circled by a pathologist. Provide the percentage of tumor cells present, minimum 10%. |
| 10 mm square | Cell block, formalin fixed paraffin | Formalin-fixed, paraffin-embedded block | Ambient | Ambient | Formalin-fixed paraffin-embedded cell block slides. Transport and store slides at ambient temperature. Three unstained sections FFPE cell block tissue on charged, unbaked slides. Provide the percentage of tumor cells present, minimum 10%. |
| 10 mm square | Aspirate, fine needle | Slide | Ambient | Ambient | One alcohol fixed cytology slide. Tissue adequacy must be assessed by cytopathologist. |
Stability
| Environmental Condition | Description |
|---|---|
| Ambient | FFPET slides and scrolls, cell block slides and alcohol fixed slides are stable at ambient temperature indefinitely. |
| Refrigerated | FFPET slides and scrolls, cell block slides and alcohol fixed slides are stable at ambient temperature indefinitely. |
| Frozen | Unacceptable |
Days Performed
Mon - Fri
Turnaround Time
3 days
Methodology
| Name | Description |
|---|---|
| Real-Time Polymerase Chain Reaction (RT-PCR) |
Special Info
Detects 51 known mutations of the EGFR gene.
Clinical Info
The EGFR Hotspot PCR Analysis rapidly identifies specific EGFR mutations in solid tumors, guiding diagnosis, prognosis, and treatment planning. The EGFR Hotspot PCR Analysis rapidly detects 51 biomarkers, including clinically relevant, activating mutations in EGFR exons 18-21, using real-time PCR technology. EGFR hotspot testing is indicated in non-small cell lung cancer to determine eligibility for targeted therapies or to determine if EGFR-targeted therapy resistance has developed. This test only detects hotspot mutations in EGFR. It should be considered when EGFR-only targeted testing is required (i.e., rapid detection of known EGFR resistance mutations), when tumor material is limited, and/or when rapid turnaround time is necessary. For more comprehensive solid tumor testing, please refer to the Targeted Oncology Panel.
Clinical Limitation
The assay limit of detection (LOD) is 5% variant allele fraction. Specimens must contain at least 10% tumor cells; if less than 10% tumor is utilized, a negative result is of indeterminate significance. Only 51 EGFR variants can be detected by this technology; refer to the gene list on the Supporting Document tab for specific details. A negative result does not preclude the possibility of an alternative hotspot variant. Tumor heterogeneity, tumor burden, specimen degradation, or other technology limitations may affect the sensitivity and LOD. Interfering substances, specifically formalin, decalcification agents, fixation agents containing heavy metals, or preservation of buffy coats using Hank’s Balanced Salt Solution (HBSS), can affect assay performance. This test cannot distinguish between somatic and germline variants.