Table 2 A comparison of all the currently available CTC methods using whole blood, where each method is compared with the other methods. From a clinical perspective, we found the data describing the clinical detection to be the most important. This table shows size-based separation, density-based separation, and combined separation methods
From: Technologies for circulating tumor cell separation from whole blood
Separation category subcategory | Technology | Company | Selection criteria | Key features | Capture efficiency | Purity | Recovery | Viability | Sample volume | Throughput | Clinical detection |
|---|---|---|---|---|---|---|---|---|---|---|---|
Size-based separation | Â | Â | Â | Â | Â | Â | Â | Viable | Â | Â | Â |
Membrane microfilters |  | 8-μm pores | Extraction with reverse flow; easy modification for application; 1-in. WC pressure | 90% | 74% | 90% | Viable | 7.5 ml | 45 ml/h | 76% (16/21) | |
|  | Two 5-μm gaps | Simple operation; transparent membrane; real time changes to the flow characteristics; 5–15-kPa pressure | 80% | 83% | 95–96% | N/A | 2 ml | 0.7 ml/h | 100% (5/5) | ||
SB [33] |  | 8-μm holes on bottom, 40-μm holes on top | Capture is achieved by a gap between the top and bottom porous membranes; reduction in mechanical stress | 78–83% |  |  | 71–74% | 1–7.5 ml |  |  | |
FAST [34] | Clinomics | 8-μm pores + stably-held liquid | Simple use; ultrafast cell enrichment; transparent membrane; 1-kPa pressure | 96% | > 2.5 log depletion | 96% | Viable | 3 ml | 180 ml/h (3 ml/min) | 83.3% (15/18)a | |
Microfluidic sorting | Angle | 10–4.5-μm gap size | Easy operation; multiple use; 99-mbar pressure | 42–70% |  | 54–69% | 99% | 4 ml | 10 ml/h | 38.5% (10/26) | |
|  | 8-μm circular cavities; or 5–9 × 30-μm or 8 × 100-μm rectangular cavities | Integrated enumeration, staining, and washing | 80–97% |  | 70–96% | 98% | 1–3 ml | 12 ml/h | 80% (40/50) | ||
Density-based separation | OncoQuick [74] | Greiner Bio-One | Density | Elimination of lymphocytes and mononuclear cells; separation media for additional separation | Â | Â | 87% | N/A | Â | Â | 23% (14/61) |
AccuCyte [75] | RareCyte | Density | Sequential density fractionation; automated | Â | Â | 90% | N/A | Â | Â | 81% (22/27) | |
Combined methods | CTC-iChip [76] |  | EpCAM/CD45 + size | Two operation modes; long setup time; can be automated; 140-kPa pressure | 77–98% | Positive, > 3.5 log depletion; negative, > 2.5 log depletion | 99.50% |  | 10 ml | 8 ml/h | Positive mode, 90% (37/41) |
Negative-negative microfluidic platform [77] |  | CD45 + size | Negative immunomagnetic enrichment and negative selective microfluidic chip without sample transfer |  | 90% | 90% |  | 2 ml | 2 ml/h | 100% (15/15) |