Generally speaking, you should size your syringe to your maximum injection dosage. For example, if you are taking 20 units per shot, you could use either a 0.5cc/50 unit syringe or a 0.3cc/30 unit syringe. If you are taking 60 units, use a 1cc/100 unit syringe. Since the markings are wider apart the smaller the syringe size, it is generally easier to read a 35 unit dosage on a 0.5cc/50 unit syringe than on a 1cc/100 unit syringe. It is easier to read a 15 unit dosage on a 0.3cc/30 unit syringe than on a 0.5cc/50 unit syringe. There is nothing wrong with doing a 15 unit dosage on a 1cc/100 unit syringe, but remember, being precise with your dosage leads to better diabetes management.
UltiCare needles are available with 28 gauge, 29 gauge, 30 guage, and 31 gauge sizes. This number represents the U.S. standard sizing for stainless steel hypodermic tubing. The actual dimensions are:
Outside Diameter Inside diameter Nominal Wall Thickness
28 gauge .014 inches .0065 inches .0035 inches
29 gauge .013 inches .0065 inches .003 inches
30 gauge .012 inches .0055 inches .003 inches
31 gauge .010 inches .0045 inches .0025 inches
The larger the gauge size, the smaller the outside diameter, and therefore, the smaller the hole put in you. One would initially think, "The smaller the hole, the less discomfort, the better!" This is not always the case. Please note that the inside diameter remains the same for 28 and 29 gauge, and though the 30 gauge inside diameter is smaller on the 29 gauge and 30 gauge, the nominal wall thickness is smaller. This means that the needle will be weaker and more likely to bend if you do not inject straight in, or have particularly tough skin, or a lot of callouses. You and your physician or diabetes educator must be the judge of your comfort level and needs.
Please note, that the standard length of the 28 gauge and 29 gauge needle is 1/2 inch while the 30 gauge and 31 gauge needle is only 5/16 inch hence the term "short needle". This shorter needle is required to prevent the much thinner needle from bending. There is also a psychological incentive to use a shorter needle, but most adults will find that the 29 gauge will work just fine as they need a slightly larger diameter and greater length.
Please consult your physician or diabetes educator before making any changes in needle size, length, or capacity.
