On my unit, we've been having issues with abnormal lab values based purely off the fact that labs are not being drawn in the correct order. Who would've known that which color tube you drew first would affect the results of the others?  One of our nurses wrote this brief article about drawing labs from a central line.  It's a super quick and interesting read.

Have you ever looked at your patient’s labs and think “there is no way these labs are correct”? When drawing blood from a Central Venous Access Device (CVAD) you could inadvertently contaminate the blood sample with IV fluids and medications. This contamination causes extra work, such as the nurse having to draw the labs again, patients having more blood drawn and lab having to run the test again. This quick tip sheet is to remind us about the proper procedure to draw labs from a CVAD while avoiding contamination.

1.      Choose the largest diameter lumen that is the most distant in the patient’s body. The distal port (16 gauge) of the CVAD is recommended.

2.      If IV solutions or medications are infusing through the CVAD, determine whether stopping the infusion will affect the patient’s hemodynamic stability.

  1. If drawing for a drug level, DO NOT draw from the port the medication is infusing (i.e.: heparin).
  2. If stopping the infusion will not affect hemodynamic stability, stop the infusion for 3 to 5 minutes before drawing the specimen.
  3. If stopping the infusion may cause instability, draw the specimen from a different site.

3.      Flush the port with 10 ml normal saline.

4.      Then withdraw and discard a minimum of a 6cc for waste.

5.      Draw labs in the appropriate order:

a.      If using a VACUTAINER:

    i.      RED TOP (non-additive tube)

   ii.      LIGHT BLUE TOP (citrate tubes)

   iii.      GREEN TOP (heparin tubes)

   iv.      LAVENDER TOP (EDTA tubes)

   v.      GOLD TOP, Speckled, Mottled (separator tubes/clot activators)

   vi.      GRAY TOP

b.      If using a SYRINGE:

    i.      LIGHT BLUE TOP (citrate tubes)

    ii.      GREEN TOP (heparin tubes)

    iii.      LAVENDER TOP (EDTA tubes)

    iv.      GRAY TOP (Oxalate or sodium fluoride)

    v.      GOLD TOP, Speckled, Mottled (separator tubes/clot activators)

    vi.      RED TOP (non-additive tube or serum tube)

6.      Don’t forget to flush the line with 10cc-20cc normal saline when complete to keep the line patent. 

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AuthorCourtney Tracy