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Table 1 Assay performance parameters

From: Advances in rare cell isolation: an optimization and evaluation study

Parameter

Optimization goal

Definition

Dependencies

Limit of detection (LOD)

0.24 cells/mL peripheral blood

Detection of at least one cell of interest in 4.2 mL blood or 2.5e7 total cells

Test sensitivity, recovery, Ltotal

Enrichment factor

>500

Ratio between the cell-of-interest frequency before and after enrichment

Depletion factor and recovery

Depletion factor

>625

Ratio between the leukocyte amount before and after enrichment

Bead amount high

Recovery

80%

Measure of target cell loss

Bead amount low

Initial leukocyte amount, Ltotal

2.5 × 107

Assay start with leukocyte cell count

Blood volume 3–7 mL, enrichment factor, cell of interest frequency,

Residual leukocytes, Lfinal

2 × 104 to 4 × 104 cells

Leftover leukocytes after depletion

Depletion factor

Assay time

2 h

Complete assay time including isolation and analysis

RBC lysis quality and enrichment factor