Home / Knowledge / Blood tube additives and cap colours
Blood tube additives and cap colours
Cap colour is a convention, not a standard, and it is the most common source of confusion in a cross-border tube order.
Most laboratories identify a vacuum tube by the colour of its cap, and within one market that works because everyone uses the same convention. Across markets the convention varies, and a colour that means one additive in one country can mean another elsewhere.
The additive is the thing that actually matters, because it determines what the sample can be used for. A tube ordered on colour and delivered with a different additive is not a cosmetic problem; it is a box of tubes that cannot be used for the test they were bought for.
So specify by additive name and by draw volume in millilitres, and treat cap colour as a preference to be confirmed rather than as the specification. If the order needs a particular colour for local familiarity, say so as a separate requirement.
This is also worth writing into a purchase order rather than leaving in an email thread. An order that states the additive is checkable on receipt; an order that says "as before" is only checkable by whoever remembers.
Specifications
| Colour | A market convention, not a standard |
|---|---|
| Specify by | Additive name and draw volume |
| If colour matters | State it as a separate requirement |
| Put it | On the purchase order, not in an email |
Related Products
Specifying a vial closure system
The vial, the stopper and the cap are one system, and a mismatch is discovered by a filling machine rather than by a goods-in inspector.
PPE standards by destination
Two identically described masks can be certified against different test methods, and only one of them may be acceptable where you sell.
Analyzer and strip continuity
An instrument is bought once and fed every month, so supply continuity of the consumable matters more than the instrument specification.
Send the SKU and target quantity
Name the item, the size or additive, the quantity and the destination market. We reply from the catalog rather than with a form to fill in.