A variety of syringes and needles are used to inject medication. Tuberculin and insulin syringes are small syringes with fine needles . They are used to inject medication under the skin.

Modern Syringes

Needles may be permanently attached to syringes or require assembly. Needle gauge indicates the width of the needle. Needles numbered with a high gauge are the thinnest.


The procedure for using a syringe is similar no matter what syringe is used. Aseptic technique is essential. Dispose of the syringe and needle safely after using.

Tuberculin Syringes

Tuberculin syringes hold up to one half to one cubic centimeter of fluid. They are used to administer medication and perform a tuberculosis test called a PPD. Syringes are marked in increments of 0.01 cc. Needles are often 26 or 27 gauge in diameter and 1/2 to 5/8 inch in length.

Insulin Syringes

Insulin syringes come in one third, one half, and one cubic centimeter sizes. They are marked by units of insulin. A one cubic centimeter syringe can hold up to 100 units of insulin. Insulin needles are extremely fine and flexible. They range from 29 to 31 gauge in diameter and from 5/16 inch to 1/2 inch in length


It is essential that people administering injections receive appropriate training. Syringes and needles must never be shared or reused. Several communities offer locations for safe disposal of used syringes and needles. Check with your local Health Department.