Our system currently uses the glass 4.5 mL fill 3.2% BD Vacutainers for our coag samples. Because BD will be discontinuing the glass pediatric tubes and replacing it with the plastic 2.7 mL fill 3.2% tubes, we have decided to switch completely to the plastic.  Best practice (and CLSI recommendation) is to validate to prove there is no difference in results between the two tube types. 

 

Has anyone actually done this? How many samples? What was your range of results (CLSI mentions a difference may only be seen with prolonged samples)? Did you validate your entire test menu, or just PT/PTT?

 

 

We just completed this study in January. We ran 50 PT/APTT patients, across the normal and therapeutic ranges to include heparin therapy patients. We also ran 20 fibrinogens and D-Dimers-we are a small lab so that is our complete testing menu. I used the CAP guidelines-+/- 15% for PT/APTT and +/- 20% for fibrinogen and D-Dimer.

Edited April 16, 201510 yr by adantonio

We did this some time ago, simular to adantonio, above.  I believe for our "batch" tests like free-PS, PC, LAs, etc, we just repeated the normal range study.

 

Scott

Thanks guys!  Next question: how did you go about getting both tubes from patients who would be at the higher end for PT, fibrinogen, and DDimer?  We are not allowed to simply have the phlebs draw and extra tube on patients. PTT and anti-Xa I plan on just spiking with heparin.

Geez, I am pretty sure that we just drew both types of tubes for our comparisons.

 

I think you have to realize that if the two do NOT match within whatever acceptability you use, then you will end up doing a normal range study for all of those tests anyway in order to validate your new tube normal and therapuetic ranges.  So maybe you should just go ahead and do that? 

 

Scott

Don't forget to issue new normal rnages too...