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Short answer: for a capillary (skin-puncture) collection, the order of draw, properly called the order of collection, is the sequence in which microcollection tubes are filled when more than one is needed. A laboratory procedure and a tube maker’s FAQ agree on the core of it: EDTA tubes first, then other additive tubes, then serum tubes. The laboratory that receives the specimens, and the instructions for use (IFU) of the tubes you stock, decide the exact sequence for your site.
This page describes products and general use; it is not medical advice. It does not describe how to perform a puncture. Staff follow their facility protocol and the tube maker’s IFU for that.
Who uses it: laboratory and clinic staff who stock or receive microcollection tubes, supply buyers, and students learning why tube sequence is a written rule. If you also collect venous samples, see blood draw tube colors and the venous order of draw; the two sequences are not the same.
What is the order of draw (in phlebotomy and for a phlebotomist)?
The order of draw is the fixed sequence in which collection tubes are filled when several are taken from one patient at one time. Alberta Precision Laboratories states the reason in its skin puncture procedure: “Blood collection tubes must be filled in a specific order to minimize contamination of sterile specimens and avoid possible test result error due to cross contamination from tube additives.” For a phlebotomist the practical point is that there are two written sequences, one for venous tubes and one for skin-puncture microcollection tubes, and the capillary one is the subject of this page.
Capillary order of draw: the sequence
The table sets out the sequence given in each of two documents. It is a comparison of documents, not a recommendation for any one site.
| Step | Alberta Precision Laboratories, PA03-010 (Rev 2.00) | BD Microtainer K2EDTA product page FAQ |
|---|---|---|
| 1 | Capillary tube blood gas; NMS card | Not listed |
| 2 | EDTA microcollection tube | EDTA tubes |
| 3 | Other additive tubes: heparin microcollection tubes including those with gel; sodium fluoride EDTA microcollection tubes | Other additive tubes |
| 4 | Serum microcollection tubes including those with clot activators and gel | Serum tubes |
Sources: Alberta Precision Laboratories, “Skin Puncture Order of Collection”, PA03-010 Rev 2.00; BD, Microtainer K2EDTA product page 365974, FAQ on order of draw (both checked 2026-11-04; full links under Sources).
The two agree on the order of the three tube groups. They differ in that the Alberta procedure also places a capillary blood gas tube and the newborn screening (NMS) card first, while the BD FAQ does not mention them. Alberta adds that the same order applies when blood collected by syringe is transferred into microcollection tubes.
The capillary blood collection guide records a third statement: the Sarstedt Microvette page gives EDTA, then lithium heparin or lithium heparin gel, then fluoride, then serum or serum gel, citing the CLSI standard. That is the same EDTA-first, serum-last pattern.
Order of draw for capillary puncture compared with venous
The venous sequence in CLSI GP41, as summarized on the blood draw tube colors page, is: blood culture, sodium citrate, serum, heparin, EDTA, then the gray glycolytic-inhibitor tube. Placed side by side:
| Position of EDTA | Position of serum | Source |
|---|---|---|
| First of the additive tubes | Last | Capillary: Alberta PA03-010; BD FAQ |
| Fifth, after serum and heparin | Third, before heparin and EDTA | Venous: CLSI GP41 as summarized on CASRAI’s tube colors page |
The practical consequence is that a rule remembered from venous work, with EDTA near the end, cannot be applied to microcollection tubes. Alberta’s procedure sends venous readers to a separate document (PA03-005) for that reason. The documents above give the contamination wording quoted above as the general purpose of any order of draw; they do not give a separate explanation of why the capillary and venous sequences differ, so this page does not offer one.
Which document governs at your site
- The tube IFU. BD describes K2EDTA microtainers as containing enough K2EDTA for 250-500 μL of blood, about 1.0 mg per tube. Fill volume and additive are product-specific, so read the insert for the product in your drawer.
- Your facility or reference laboratory procedure. Alberta’s document tells readers to refer to its test directory for the collection and handling of each test, so a test-specific instruction can sit outside the general sequence.
- The standard cited, and its edition. Both documents point to the CLSI capillary standard. Alberta lists GP42-A6, 6th edition, 2008; BD cites the same title under the older number H4-A6 (Vol. 28 #25, September 2008). They are the same 2008 document under two numbering schemes. A later edition may exist; check which edition your own procedure names rather than assuming.
- Syringe transfers. Alberta applies the same sequence when syringe-collected blood is moved into microcollection tubes.
Common mistakes
- Applying the venous sequence to microcollection tubes (or the reverse).
- Treating a vendor FAQ as the full procedure: the BD FAQ lists three groups and omits the blood gas and NMS card steps that Alberta includes.
- Citing an old standard number (H4-A6) as if it were a different, newer document from GP42-A6.
- Assuming cap colour tells the sequence: colours vary by manufacturer. For specific additives see green top tubes, red top tubes and gray top tubes.
Supplies that go with microcollection work
Staff handling specimens also need protective garments; see medical apparel. For the puncture device itself, see what a lancet is.
Frequently asked questions
What is the order of draw?
It is the written sequence for filling several collection tubes from one collection so that additive from one tube does not contaminate another. Venous and capillary collections have different sequences.
What is the order of draw in phlebotomy?
For venous tubes, CLSI GP41 gives: blood culture, sodium citrate, serum, heparin, EDTA, gray (see the venous chart). For skin puncture, Alberta Precision Laboratories gives: capillary blood gas and NMS card, EDTA, other additive tubes, serum tubes.
What is the order of draw for a phlebotomist doing a capillary puncture?
Both documents agree on EDTA, then other additives (heparin, fluoride), then serum. The facility’s own procedure and the tube IFU take precedence.
Does the order of draw differ when blood is transferred from a syringe into microcollection tubes?
Alberta’s procedure says to use the same order for transferring syringe-collected blood into microcollection tubes.
Sources
- Alberta Precision Laboratories (Alberta Health Services), Skin Puncture Order of Collection, PA03-010 Rev 2.00, albertahealthservices.ca, checked 2026-11-04. It cites CLSI GP42-A6 (2008) and BD Microtainer insert 8363931 (03/2011).
- BD, Microtainer K2EDTA tube product page 365974, bd.com, checked 2026-11-04.
- CASRAI guides capillary blood collection and blood draw tube colors for the Sarstedt statement and the CLSI GP41 venous sequence, each checked 2026-10-30.
