Phlebotomy: 25 Gauge Needle Question

Nurses General Nursing

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Specializes in Community Health, Med-Surg, Home Health.

I have been drawing blood as a phlebotomist for over 15 years before becoming a nurse. I was always told by lab techs and other nurses that drawing blood from a 25 gauge butterfly needle can hemolyze the blood, so, I would use size 23.

Now, working occasionally in the Coumadin clinic, I am encountering patients who I really cannot obtain a sample, and today, I had to resort to using a 25 gauge so that I would not blow the veins of this frail, elderly patient. The sample did make it to the lab, and a successful reading came, but I am concerned, because I see many patients like this, whose veins are blown from many hospital admissions and frequent visits to the labs and clinic.

What does anyone know about this? Does, in fact, the 25 gauge needle ruin the sample? Thanks!

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I have never heard of that. When I used to have to order butterfly needles, I did so through Quest Diagnostics. THEY supply them, I dont think that they would stock or send out anything that would cause harm. Ive never gotten any complaints about samples that I have drawn with them either.

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Specializes in Pediatrics (Burn ICU, CVICU).

I use them on a regular basis...typically don't have a problem.

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we use 25ga ABG kits.

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Specializes in ER/EHR Trainer.

Our butterflies are 23 and 25 gauge...use what works.

Maisy

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Specializes in Community, OB, Nursery.

I've never ever heard that.

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Specializes in Cardiac/ED.

I worked as a phleb for over 20 years..(now one semester from my ADN) Drawing with a 25g is fine...hemolysis is of course a concern, one has to carefully monitor the amount of vacuum that apply to the syringe. Rest assured if the sample had hemolysis that would have interfered with the results I am sure the Lab scientist would have rejected it...they work under a license just like RN's and therefore held to their own laws and regulations.

One of my favorite methods of collection from extremely difficult draws, was a straight 25g needle on a 3ml syringe...you don't get much but it could be stretched for what you need.

P2

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Specializes in ER.

If it was aproblem they wouldn't make that gauge needle, another thing to try to stop veins from blowing is to not apply a tourniquet for lab draws.

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here's an excerpt from the abstract from the sample study addressing the question at hand:

"Routine coagulation tests were assayed in blood specimens collected from 22 consecutive patients in three separate, sequential phlebotomies, using butterfly devices with different needle sizes. Test results of samples collected with 23 and 25 G needles were compared with those obtained with the currently recommended 21 G needle. Although both the prothrombin time and activated partial thromboplastin time displayed a trend towards lower values employing the smaller 23 and 25 G needles, results did not differ significantly from the reference 21 G needle specimen, with the exceptions of D-dimer (25 G versus 21 G needle, 186 ± 70 versus 178 ± 66/ml, P

Lippi, G., G. L. Salvagno, et al. (2006). "Influence of the needle bore size on platelet count and routine coagulation testing." Blood Coagul Fibrinolysis 17(7): 557-61.

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I am currently a phlebotomist and have been for 24 years. I am also a nursing student.

A 25g needle can cause hemolysis just as any need can if too much force is exerted. I do not use butterflies at all except to draw infants. I typically use a 23g straight needle or 21g vacutainer.

The trick to avoiding hemolysis is a steady and controlled draw. As for coag specimens, I do not believe hemolysis is a factor. Hemolysis affects potassium levels and may affect accurate CBC results.

Rich

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Specializes in Spinal Cord injuries, Emergency+EMS.

also depends on what you want the samples for ...

our haematolgy analyzers seem to cope reasonable well with when the samples taken at the same time from the same stick for biochemistry analysis come back as haemolysed

we were talking about this and the 'worst case scenario' options to get that sample you REALLY REALLY need, and given that the labs can do capilliary samples for neonates/ paeds and in critical care anyone with an art line gets arterial samples sent ... depending on the skills or your team ( docs and nurses) alternative approaches may pay off

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Specializes in Community Health, Med-Surg, Home Health.

Thank you everyone for your phenomenal answers.

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