Cryopreservation of CTCs for biobanking and sample logistics

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Cryopreservation protocol enables long term storage of PBMC before CTC enrichment, making it possible to biobank samples and ease sample logistics.

Most CTC enrichment procedures start with the collection of one or more tubes of whole blood. Once drawn, these blood tubes have a relatively brief window where they can be processed, typically 36 hours. The use of a fixative inside the tube can extend this window to 96 hours, but may come at the expense of the types of analyses that can be performed (i.e. it may limit it to just enumerating the CTCs). It is a clear advantage to be able to retain the samples for longer before processing:


  • Preserve the integrity of the sample during transport and storage
  • Ease the logistical burden on clinical collections team and lab processing center
  • Batch process samples to reduce time and expense
  • Biobank samples for analysis at later time points


The protocol here describes a method for collecting blood in BD Vacutainer® CPT™ Tubes for easy recovery of the PBMC fraction. The PBMCs can be frozen and retained indefinitely for processing at a later date. The protocol describes the methods for both the freezing and thawing process, both of which are critical to maintain the integrity of the sample. After thawing, the PBMCs can move directly into the protocol for the IsoFlux CTC Enrichment Kit.