Circulating Tumor Cells (CTC) for Breast Cancer by CellSearch, Blood
Method Description Describes how the test is performed and provides a method-specific reference
The CellSearch system consists of a CellTracks AutoPrep System and a CellTracks Analyzer. The AutoPrep system uses a ferrofluid reagent conjugated with monoclonal antibodies to epithelial cell adhesion molecule (EpCAM) to immunomagnetically separate epithelial cells from other blood components. Because the epithelial cell enrichment with EpCAM does not result in a completely pure epithelial cell population, the CellSearch System also utilizes 3 stains (DAPI, phycoerythrin [PE]-labeled cytokeratins [CK], and allophycocyanin [APC]-labeled CD45) to help distinguish true circulating tumor cells (CTCs) from contaminating leukocytes. DAPI stains the nuclei of cells and helps distinguish true cells from nonspecific debris. CTCs are identified with PE-labeled antibodies to CK 8, CK18, and CK19. Leukocytes are identified with APC-labeled antibodies to CD45. Cells that are DAPI+/CD45-/CK+ are classified as tumor cells, while all other staining combinations represent noncirculating tumor cells (eg, leukocytes or noncellular debris). (Riethdorf S, Fritche H, Muller V, et al: Detection of circulating tumor cells in peripheral blood of patients with metastatic breast cancer: a validation study of the CellSearch machine. Clin Cancer Res 2007 Feb 1;13:920-928)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Monday through Friday, Sunday
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Performing Laboratory Location The location of the laboratory that performs the test