Considerations in the development of circulating tumor cell technology for clinical use

Table 3 CTC Assay Clinical Readiness Evaluation

Assay Validation
Pre-Analytic	How is specimen collected (venous route, body position, draw order, tourniquet time, needle bore, tube type)?
	When is specimen collected (time of day, relative to treatment, relative to infusates)?
	How is specimen stored (time and temperature)?
	How is specimen handled (shipping, transfers)?
Analytic	Sensitivity (lower limit of quantitation)?
	Reportable range?
	Specificity?
	Reproducibility?
	Robustness?
Post-Analytic	How is data reported?
	How is data analyzed?
	What are the reference intervals?
Clinical Feasibility
• Are there analytically valid results when tested in appropriate preclinical models?
○ with use of clinically relevant/feasible specimen acquisition?
○ with use of clinically relevant specimen handling procedures (both at the point of acquisition and in the receiving laboratory)? These processes should be tracked and recorded.
○ with use of clinically relevant collection scheduling?
Therapeutic Relevance
• For predictive biomarkers, is there a relationship between dose/exposure, quantifiable target modulation, and disease outcome?
• For prognostic biomarkers, is there a relationship between baseline levels and survival?

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