Thank you for your inquiry.
There are differences between tuberculin and insulin syringes. The two links copied below will take you to websites that discuss these differences.
This does not preclude insulin syringes from being used to administer allergy injections, but one has to be very careful about the conversion units involved. In addition, syringes specially designed to administer allergy injections are also available for purchase at suppliers. These are designed specifically for that task.
It's All in the Syringe
What is the difference between a tuberculin syringe and an insulin syringe?
Thank you again for your inquiry and we hope this response is helpful to you.
Phil Lieberman, M.D.