The correct color tube for a Complete Blood Count (CBC) is lavender (purple).
Lavender (Purple) Tube for CBC
According to the UNC Medical Center's Evacuated Blood Collection Tube Guide, the lavender (or purple) top tube is specifically used for CBC tests.
Why Lavender?
- Anticoagulant: The lavender tube contains the anticoagulant (K2)EDTA. EDTA prevents the blood from clotting, which is crucial for accurate cell counts and analysis in a CBC.
- Specific Tests: Besides CBC, this tube is also used for related tests including:
- Differential (Diff)
- Reticulocyte count (Retic)
- Sedimentation Rate
- Other tests such as FK506, Cyclosporin, Platelet Antibody, Coombs, and Flow Cytometry.
Tube Contents and Use:
| STOPPER COLOR | CONTENTS | USES/COMMENTS |
|---|---|---|
| Lavender ("Purple") | (K2)EDTA | CBC/Diff/Retic/Sed Rate, FK506, Cyclosporin, Platelet Ab, Coombs, Flow Cytometry |
Practical Insights:
- Proper Fill: Ensure that the tube is filled to the marked line to maintain the correct ratio of blood to anticoagulant for accurate test results.
- Gentle Mixing: Immediately after collection, gently mix the lavender tube by inverting it several times (usually 8-10 times) to ensure the EDTA is well mixed with the blood.
- Avoid Clots: Incorrect mixing can lead to clots forming in the tube, making the sample unsuitable for analysis.
By using a lavender (purple) tube, healthcare professionals ensure the accurate analysis of the blood sample for a CBC, enabling precise diagnostics.
