Order of Draw and Tube Mixing

Correct order of draw is essential to preserve specimen quality and reduce pre-analytical error. During multiple-tube blood collection, tubes must be filled in the approved sequence to minimise additive carryover, contamination, clotting problems, and testing interference that may affect the accuracy of results.

All blood specimens shall be collected only by trained and authorized personnel using the laboratory’s approved collection devices, containers, and additives.

Order of Draw

• • For multiple-tube venous blood collection, follow the approved order below:

Blood Culture → Citrate → Serum → Heparin → EDTA → Fluoride/Oxalate

• • This order applies whether blood is collected using a syringe, tube holder, or pre-evacuated tube system.

Why This Matters

• Collecting tubes in the wrong order may cause carryover of additives from one tube to another. This can affect specimen integrity and may produce inaccurate or spurious results. In some cases, repeat specimen collection may be required.

Identify the Correct Tube

• The correct tube shall be identified primarily by tube type and additive. Closure colour should be used only as a local visual guide for the approved tube system, as tube colours may vary between manufacturers.

• Always refer to the laboratory’s approved tube guide and specimen collection manual.

Fill the Tube Correctly

• Allow each evacuated tube to fill naturally until the vacuum is exhausted and blood flow stops. Do not force blood into the tube by pressing the syringe plunger, as this may cause haemolysis.

• When syringe transfer is required, use the approved blood transfer device and allow the tube vacuum to draw the blood to the intended level.

• Correct fill volume is especially important for citrate tubes, as underfilling or overfilling may alter the required blood-to-additive ratio.

Mix Immediately After Collection

• Each tube shall be mixed immediately after collection by gentle inversion. One complete inversion means turning the tube 180° and back. Tubes must not be shaken.

• Use the approved number of inversions for the specific tube type. As a general guide:

• Citrate: 3–4 inversions
  Serum / RST: 5 inversions
  SST: 5–6 inversions
  Heparin, EDTA, Fluoride: 8–10 inversions

• Where applicable, follow the approved manufacturer’s instructions or local laboratory validation.

Special Collection Notes

• When a winged collection set is used and a citrate tube is the first specimen required, collect a discard tube first to clear the tubing air space and ensure correct fill volume.

• When collecting blood cultures using a winged set, fill the aerobic bottle first, followed by the anaerobic bottle.

Non-Conforming Specimens

• Samples that do not meet requirements for identification, container type, fill volume, clotting status, handling, or transport shall be managed according to the laboratory’s specimen acceptance and rejection policy.

• If a compromised but clinically critical or irreplaceable specimen is accepted, the limitation shall be documented and an appropriate cautionary note shall be included in the report where relevant.

Quick Reminder

• Follow the approved order of draw.

• Allow the tube to fill completely.

• Mix immediately by gentle inversion.

• Use the poster and tube guide for quick reference.

1️⃣: Assemble equipment.

1. A supply of laboratory samples tubes, which should be stored dry and upright in a rack. Check the expiry date of the tubes;

2. Well-fitting, non-sterile gloves;

3. An assortment of blood-sampling devices (needles, syringes) of different sizes;

4. A tourniquet;

5. An alcohol hand rub;

6. 70% alcohol swabs for skin disinfection;

7. Gauze or cotton-wool ball to be applied over puncture site;

8. Laboratory specimen labels;

9. Laboratory requisition forms;

10. A puncture-resistance sharps bin.

2️⃣: Identify and prepare the patient.

1. Introduce yourself to the patient, and ask the patient to state their full name.

2. Check that the laboratory requisition form matches the patient’s identity to ensure accurate identification.                              (Double confirmed using IC against requisition form)

3. Ask whether the patient has allergies, phobias or has ever fainted during previous blood takings.

4. If the patient is anxious and afraid, reassure the patient.

5. Make the patient comfortable in a relaxed position.

6. Discuss the procedure to be performed and obtain verbal consent. The patient has a right to refuse the procedure at any time before the blood sampling.

3️⃣: Select the site.

1. Extend the patient’s arm and inspect the antecubital fossa or forearm.

2. Locate a vein of a good size that is visible, straight, and clear. 

3. The median cubital vein lies between the muscles and is usually the easiest to puncture.

4. The vein should be visible without applying a tourniquet. 

5. Locating the vein will help in determining the correct size of the needle.

6. Apply the tourniquet about 4 - 5 finger widths above the venepuncture site and re-examine the vein.

4️⃣: Perform hand hygiene and put on gloves.

1. Perform hand hygiene and afterward, put on well-fitting non-sterile gloves.

5️⃣: Disinfect the entry site.

1. Clean the site with a 70% alcohol swab adequately and allow to dry completely (about 20 - 30 seconds).

2. Apply firm but gentle pressure. 

3. Start from the center of the venepuncture site and work outward to cover an area of 2cm or more.

4. Allow the area to dry. 

5. Failure to allow enough contact time increases the risk of contamination. 

6. DO NOT touch the cleaned site; in particular, DO NOT place a finger over the vein to guide the shaft of the exposed needle. 

7. If the site is touched, repeat the disinfection.

6️⃣: Take blood.

1. Anchor the vein by holding the patient’s arm and placing thumb BELOW the venepuncture site.

2. Enter the vein swiftly at a 30 degree angle and continue to introduce the needle along the vein until the blood flow is established.

3. Once the blood flow is established, maintain the position of the needle, release the tourniquet and pull the plunger of the syringe lightly. 

4. Let the blood flow into the syringe until sufficient volume of blood has been collected.

5. Withdraw the needle gently and apply gentle pressure to the site with a clean gauze or dry cotton-wool ball.

7️⃣: Fill the laboratory sample tubes.

1. Follow the correct Order of Draw for blood collection tubes to avoid cross-contamination of additives between tubes.

2. Place the tube into a rack before filling the tube. 

3. Pierce the rubber stopper on the tube with the needle directly above the tube using slow and steady pressure to fill the tube.

4. DO NOT recap and remove the needle.

5. DO NOT remove the stopper because it will release the vacuum.

6. Gently invert the tubes according to the required number of times. 

7. Avoid vigorous mixing to avoid hemolysis.

8️⃣: Clean contaminated surfaces and complete the procedure.

• 1. Discard the used needle and syringe into a sharp yellow bin.

  2. Check the label and forms for accuracy.

  3. Discard used items into the appropriate category of waste (yellow bin or general waste).

  4. Perform hand hygiene again.

  5. Recheck the labels on the tubes and the forms before dispatch.

  6. Inform the patient when the procedure is over.

  7. Ask the patient about their condition. 

  8. Check the puncture site to verify that it is not bleeding and thank the patient before leaving.