PST Tube Color: Heparin Gel Tube Sizes and Codes

Short answer: a PST tube is a plasma separator tube: a blood collection tube holding lithium heparin and a separator gel. Heparin-class tubes, with or without gel, are shown in the CLSI order-of-draw guidance with dark green, light green or speckled green closures, so green is the colour family to look for. The exact shade depends on the maker, so read the label on the tube you are holding.

General product information only, not medical advice. Tube choice for a given test is set by the laboratory’s collection manual and the tube manufacturer’s instructions for use.

PST tube chart: sizes from FDA device records

The rows below are BD Vacutainer and Microtainer PST products as recorded in the FDA’s AccessGUDID data through the openFDA UDI API (data last updated 2026-10-01, checked 2026-10-30). Volume, diameter and length are the values in each record; heparin units are part of the product name. Every record is marked single-use and not labeled as containing natural rubber latex.

Catalog no.	Product name in record	Draw volume	Diameter x length	Code in device description
367960	PST Gel and Lithium Heparin, 56 Units	3 mL	13 mm x 75 mm	none given
368036	PST Blood Collection Tubes	3 mL	13 mm x 75 mm	PLH 13X75 3.0 … L/GN
367961	PST Gel and Lithium Heparin, 65 Units	3.5 mL	13 mm to 100 mm (as recorded)	none given
367962	PST Gel and Lithium Heparin, 83 Units	4.5 mL	13 mm x 100 mm	none given
367963	PST Lithium Heparin (LH) Blood Collection Tubes	4.5 mL	13 mm x 100 mm	PLH 13X100 4.5 … L/GN
367964	PST Gel and Lithium Heparin, 126 Units	8 mL	16 mm x 100 mm	PLC 16X100 8.0 … GN/GR
365985	Microtainer PST Tubes with LH	not recorded	not recorded	MICRO W/MICROGARD PST MTGN
365987	Microtainer PST Tubes with LH – Amber	not recorded	not recorded	MICRO W/MICROGARD PST MTGN/AMB

Source: openFDA device UDI endpoint, AccessGUDID records for Becton, Dickinson and Company, record versions dated between 2024-02 and 2026-05. Check your product’s labelling: catalog numbers, fills and closures change, and a record can lag the box in your hand.

How to read the chart

The catalog number identifies the product, the draw volume is the nominal fill of the evacuated tube, and diameter x length is the outside size of the tube. The “code in device description” column repeats the abbreviations in the FDA record exactly as written. The record does not expand “L/GN” or “GN/GR”, so this page does not translate them into a closure colour; the colour is whatever is printed or moulded on the product you receive.

Where PST sits in the standards

The CLSI order-of-draw guidance (checked 2026-10-30) places “heparin tube with or without gel” after serum tubes and before EDTA tubes, and gives dark green, light green and speckled green as example closures for that class. A PST tube is a gel heparin tube, so it sits in that heparin position. Colour alone does not identify a product; the tube label and the manufacturer’s instructions for use state the additive and fill.

Equivalence notes

PST versus other heparin tubes

FDA’s GMDN-based device description for an evacuated anticoagulant/separator tube describes a tube containing an anticoagulant (heparin is among the examples) plus a separator, such as a gel, that separates plasma from cells. A PST is that arrangement with lithium heparin. Heparin tubes without gel fall in the same CLSI class.

PST versus micro tubes

The BD Microtainer PST records above are micro tubes with lithium heparin, listed under the same PST name. The record gives no volume or size for them, so they are not compared by size here.

Regulatory class

In openFDA classification data (checked 2026-10-30), serum separator blood collection tubes (product code JKA) and vacuum sample tubes with anticoagulant (GIM) are both device class 2 under 21 CFR 862.1675, Blood specimen collection device, in the Clinical Chemistry panel.

Common mix-ups

• PST versus SST. A serum separator tube belongs to the serum class, which CLSI lists ahead of heparin tubes; see the red-top tube additive guide for the serum side.
• PST versus pearl-top EDTA gel. CLSI lists EDTA, with or without gel separator, as a later class with lavender, pearl or pink closures. The additive differs from lithium heparin.
• Light green as the only PST colour. CLSI gives three heparin closure colours as examples, so colour alone does not identify a PST tube.
• Heparin versus fluoride tubes. The grey-closure class holds a different additive; compare it in the grey-top tube additive guide.

For the full colour-by-additive chart and the CLSI order of draw, see blood draw tube colors. For why laboratories choose plasma or serum, see serum versus plasma. For a supply list, see the phlebotomy lab supply checklist.

FAQ

What color is a PST tube?

PST tubes are heparin tubes, and CLSI gives dark green, light green and speckled green closures as examples for heparin tubes with or without gel. The FDA device descriptions for BD PST products carry “L/GN” or “GN/GR” codes. Confirm the colour on the package.

What additive is in a PST tube?

Lithium heparin as the anticoagulant, plus a separator gel. The FDA records name “Gel and Lithium Heparin” in the product names, and the GMDN definition describes an anticoagulant with a separator for plasma analysis.

Sources

• FDA, openFDA device UDI API (AccessGUDID data), https://api.fda.gov/device/udi.json, checked 2026-10-30.
• FDA, openFDA device classification API, product codes JKA and GIM, https://api.fda.gov/device/classification.json, checked 2026-10-30.
• CLSI, “Order of Blood Draw Tubes and Additives”, https://clsi.org/about/blog/order-of-blood-draw-tubes-and-additives/, checked 2026-10-30.
• 21 CFR 862.1675, Blood specimen collection device, https://www.law.cornell.edu/cfr/text/21/862.1675, checked 2026-10-30.