Syringe gauge refers to the width of a needle. Manufacturers use a standardized gauging system when they produce needles in order to ensure that needles of the same gauge are actually the same size, no matter who made them. The higher the number, the smaller the needle; a 20 gauge syringe is smaller than a 16 gauge syringe, for example. Gauge is typically printed on the sterile packaging and many companies color-code their syringes or caps to make it easy for people to spot a needle of the desired gauge when they are in a hurry.
When selecting a needle, it is critically important to use one of the right gauge. Small needles are less painful, but conversely are slower for injections and blood draws. Using syringes with a big gauge will allow for the rapid delivery of medications, but if the gauge is too big, the drugs can be delivered too quickly and may cause pain for the patient. It is also important to consider individual characteristics, as different patients have differing tolerances for needles; a small syringe gauge is more suitable for a young child, for example, or for a patient who is having repeat injections at the same site.
Small gauge needles are often used for things like needlesticks for small blood samples and deliveries of small amounts of medication. Larger needles are needed for fluid administration and boluses of drugs, where the goal is to push through a large dose of medication quickly. Catheter needles are very large gauge because tools must be threaded through the needle in the process of placing the catheter.
Care providers with experience are generally good at selecting an appropriate syringe gauge for an application. They have experience with syringe gauge measurements and various applications for syringes and they know which tool will be most suitable. Care practitioners who are just entering practice may be less certain and sometimes consult mentors or go with a generally safe size while they are learning. This does not endanger patients, although sometimes people end up with injections that are a bit more painful than they need to be.
When patients need to use needles at home to administer medication and fluids, a doctor may provide needles at the clinic or hospital, or provide patients with a prescription to take to a pharmacy. Sometimes doctors will offer patients a mix of syringe gauge options and lengths so that they can find a size they are comfortable with. Patients who are familiar with self-administration of medication, like diabetics, may request a specific gauge that they prefer at the time a prescription is written.
