Epic Sciences analyzes all nucleated cells in the blood sample. We do not sort or discard any nucleated cells. This non-biased approach ensures that no CTCs are left behind through the use of single parameter analysis.

Blood samples are shipped to our lab within 48 hours of the blood draw. When the samples are received, nucleated cells are dispensed as a monolayer on Epic Sciences’ proprietary glass microscope slides. Each slide holds three million nucleated cells, the equivalent of approximately 0.5mL of blood. Slides are then frozen and stored in the Epic Sciences biobank for future studies or may be tested directly.

Next, the slides are thawed and stained using the CTC base assay, which includes a cocktail of Cytokeratin (CK), CD45, DAPI and one or two characterization antibodies, such as a protein drug target. The slides are scanned on our whole slide fluorescent microscope.

Our digital pathology software analyzes the image files for a multitude of immunofluorescent and morphological features on all three million cells of each slide. (In some research studies, more than one slide per patient may be examined.) The hematopathology-trained algorithm incorporates numerous morphology measurements as well as expression from cytokeratin and CD45. It then proposes candidate CTCs which are confirmed by a trained reader.

If genomic analysis is needed, the coverslip is removed, and either FISH or NGS is performed. For FISH, each CTC is relocated. A trained reader scores the regional white blood cells to determine the negative control and does the same for the CTCs. Patient CTC counts are enumerated as CTCs/mL of blood, the percentage of CTCs expressing the biomarker and the results. For NGS analysis, the single cell of interest is picked from slide and relocated to an epitube where sequencing is performed.