Written and maintained by CASRAI Editorial Board
Last updated
This page describes products and general use; it is not medical advice.
A green top tube is a vacuum blood collection tube whose additive is heparin, so the sample is collected as plasma rather than serum. The closure colour tells you the additive family only; the label tells you which heparin salt (lithium or sodium) is inside. It is used by phlebotomists, clinic and laboratory staff, and the buyers who stock them; after reading you should be able to tell the two green tube types apart and know what to confirm on the label.
What a green top tube is
A green top tube is an evacuated blood tube that contains heparin, an anticoagulant, and is closed with a green stopper or green Hemogard closure. Heparin keeps the specimen from clotting, so the laboratory works from whole blood or plasma. In the U.S., a blood collection tube is a “blood specimen collection device” under 21 CFR 862.1675, defined as a device intended for medical purposes to collect and handle blood specimens, and classified as Class II (21 CFR 862.1675, checked 31 October 2026).
Who uses it: phlebotomists, laboratory technicians and clinic staff who collect specimens for tests that call for a heparin plasma sample, and the purchasing staff who stock those tubes.
What is inside: lithium heparin versus sodium heparin
Both salts are sold in green tubes. BD lists its Vacutainer green tube SKU 367886 as lithium heparin (95 USP units) and SKU 367671 as sodium heparin (33 USP units), both with a green Hemogard closure (BD product pages, checked 31 October 2026). Because the stopper colour is the same, read the label for the salt before use or before ordering.
Types and variants
| Type (BD example) | Additive | Closure | Key difference |
|---|---|---|---|
| BD Vacutainer Heparin Tube, SKU 367886 | Lithium heparin, 95 USP units | Green Hemogard | Lithium salt; plastic; larger tube |
| BD Vacutainer Heparin Tube, SKU 367671 | Sodium heparin, 33 USP units | Green Hemogard | Sodium salt; glass material code; smaller tube |
Source: BD product pages for SKU 367886 and SKU 367671, checked 31 October 2026. These are two examples from one manufacturer, not a complete list of green tubes.
Sizes and specifications
| SKU | Tube size as listed | Additive amount | Material | Pack |
|---|---|---|---|---|
| 367886 | 13×100 | 95 USP units lithium heparin | Plastic | 100 per box, 1,000 per case |
| 367671 | 13×75 | 33 USP units sodium heparin | Material code G (glass) | 100 per box, 1,000 per case |
Source: BD product pages, checked 31 October 2026. The larger tube carries the larger heparin amount in these two listings.
Green top tube versus light green PST and royal blue
Green is not the only tube colour that involves heparin. A light green gel tube is a plasma separator tube (PST) with lithium heparin and a separator gel; see PST tube color and sizes. Royal blue tubes are a separate family; see royal blue top tube. For the full colour chart and the order of draw, use blood draw tube colors, which places heparin tubes (with or without gel) after serum tubes and before EDTA. For the serum counterpart, see red top tube additive.
Safe use and handling basics
- The interior of the tube is sterile (gamma-sterilized, per BD’s FAQ). BD does not recommend re-sterilizing tubes by ethylene oxide or autoclave, because the cycle can disrupt the negative pressure and the tubes may not draw the proper blood volume.
- BD states non-gel tubes, including heparin tubes, can be centrifuged at up to 1300 RCF for 10 minutes.
- Label expiry dates on BD tubes are in Year/Month/Day format; expired or unused tubes are handled under local waste guidance.
- BD does not claim its Vacutainer tubes are endotoxin-free.
For capillary and other collection devices, see capillary blood collection.
Common mistakes
- Assuming every green closure holds the same salt. The salt (lithium or sodium) is on the label, not signalled by colour.
- Treating a light green gel PST as interchangeable with a non-gel green tube; they are different products.
- Re-sterilizing tubes. BD advises against it because of the effect on vacuum.
FAQ
What is a green top tube used for?
It collects blood with heparin as the anticoagulant so the laboratory can use plasma instead of serum. Which tests need it is set by the testing laboratory.
What is the difference between lithium and sodium heparin green tubes?
The heparin salt. In BD’s catalogue, SKU 367886 is lithium heparin (95 USP units, 13×100) and SKU 367671 is sodium heparin (33 USP units, 13×75). Both have a green closure.
Is a green top tube a regulated device?
Yes. Blood collection tubes fall under 21 CFR 862.1675 as blood specimen collection devices, Class II.
Sources
- 21 CFR 862.1675, Blood specimen collection device, via Cornell Legal Information Institute, checked 31 October 2026.
- BD Vacutainer Heparin Tube SKU 367886, BD product page, checked 31 October 2026.
- BD Vacutainer Heparin Tube SKU 367671, BD product page, checked 31 October 2026.
- Order of draw wording as published on CASRAI’s blood draw tube colors page; see also the phlebotomy lab supply checklist (checked 31 October 2026).
