In CTC analysis, result quality depends heavily on sample preparation and transport quality. This guide summarizes the critical points to ensure your blood sample reaches the laboratory under optimal conditions.
Blood Draw Protocol
- Tube choice: EDTA (lavender cap) is the most common; CellSave tubes provide stability for up to 96 hours
- Volume: 7.5–10 mL peripheral blood (20G needle, preferably not the first tube drawn)
- Order: the CTC tube must be drawn before blood cultures (contamination risk)
- Mixing: gently invert the tube 8–10 times after collection (prevents clotting)
Transport Conditions
| Tube Type | Transport Temperature | Time Limit |
|---|---|---|
| EDTA | 18–25°C (room) | 24 hours |
| CellSave | 18–37°C | 96 hours |
| CPT (Cell Preparation Tube) | 18–25°C | 2 hours (to processing) |
Common Mistakes
- Cold transport (EDTA): CTCs are cold-sensitive; ice packs cause CTC loss in EDTA tubes
- Delayed processing: beyond 24 hours in EDTA tubes, leukocyte apoptosis increases and CTCs degrade
- Over-mixing: vigorous shaking can damage CTCs
- Wrong tube: heparin (green cap) can affect CTC staining; EDTA is preferred
You can consult us about the sample shipping protocol.
Rx-only — prescription screening test. Galleri® is not a diagnostic test. A positive result does not mean a cancer diagnosis; a negative result does not rule out cancer. The test does not replace the routine cancer screenings recommended by your physician. Galleri® does not detect all cancers.