Type of Syringe for Heparin Injections?

Nurses Medications Nursing Q/A


When giving SQ heparin injections, what type of syringe do you guys use? The reason I'm asking is because for the last 13 years I've given these inj. with insulin syringes. I've recently switched units (from ortho/oncology/pain mgmt rehab to head injury rehab) and the nurses on this unit tell me that you have to use tb syringes when giving hep. inj. AM I MISSING SOMETHING OR WHAT???

10 Answers

Long Term Care Columnist / Guide

VivaLasViejas, ASN, RN

108 Articles; 9,984 Posts

Specializes in LTC, assisted living, med-surg, psych.

I've always used TB syringes for heparin injections because they are measured in fractions of a mL, NOT 'units' (as are insulin syringes). I don't know if there's much of a difference, but I was taught to use the correct type of syringe for each type of medication, and I think it should be the standard of care everywhere. JMHO. :)

TiffyRN, BSN, PhD

2,315 Posts

Specializes in Nurse Scientist-Research.

As it was explained to me the concern is that insulin used to be available in a 40units/ml mix instead of the now more common 100units/ml mixture. There were also insulin syringes that were designed for this mixture, the volume would be different obviously. My understanding is that both this mixture (40units/ml) and the syringes that went with them were gotten rid of because of med errors from not matching the insulin mixture with the right syringe.

Anyway, I guess this prompted the practice of never putting anything except insulin into an insulin syringe. I find it reassuring that when you see an insulin syringe there should always and forever be insulin in it.

Specializes in ER, ICU, Infusion, peds, informatics.

I don't use either -- unless I'm using a highly concentrated heparin that requires precise measurement.

The problem I have with using an insulin syringe is that you can't change the needle. I was taught to always change the needle after drawing up heparin to avoid bruising the tissue when injecting (tracking the heparin through all the tissue the needle goes through).

I was taught to use a tb syringe in school, mostly due to the small size of the needle and the ability to change the needle. But now you can't change the needle on many tb syringes anymore (due to the change to safety needles). So now I draw it up with a 3 cc syringe and an 18 gauge needle, and then change to a 25 gauge needle before injecting.

It is actually a lot easier this way, it can be tough to get all the medicine plus the "air cushion" in those small tb syringes when you are injecting their whole 1 cc volume, which is what you are usually injecting when giving heparin sq.


6,011 Posts


A research project at our hospital determined that by using a 3 ml syringe with a 23g needle provided less bruising and less pain for the patient.

Specializes in PCU, Critical Care, Observation.

I'm in the PCU & we use the TB syringes for heparin here.

Editorial Team / Admin

Silverdragon102, BSN

1 Article; 39,477 Posts

Specializes in Medical and general practice now LTC.

Here in the UK most heparin is in pre filled pre dosed syringes and as far as I am aware we don't use vials due to cutting down on any errors. Because the doses vary from patient to patient the syringes come in various doses which sometimes means 2 injections but have never had a patient complain especially when they have the reasons for being on it explained.


20,964 Posts

Specializes in Specializes in L/D, newborn, GYN, LTC, Dialysis.

I have always used TB syringes.

Specializes in Inpatient Acute Rehab.

I have always used a TB syringe.


105 Posts

I am just a student, but we are taught only to use TB syringes unless for some reason there was only an insulin syringe available.


381 Posts

In school we were taught 3ml syringe with a 23 gauge needle. we used this the first semester when we were in a transitional care unit. all of the heparin vials came up for each patient with the correct dosage. now in the hospital, all of our heparin comes in pre-filled syringes so we have nothing to draw up. I liked using the the 3ml because when we were drawing up the heparin there was space left inside the syringe.

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