What gauge needle is used for intradermal?

You might wonder, does the needle gauge make a difference for IVF injections? Perhaps you love using the very small needle for the Lupron injection. Can you use small needles for other injections?

Actually, the gauge and length of the needles you use for your IVF injections does matter. The majority of IVF medications are injected subcutaneously, meaning they are injected into fatty tissue underneath the skin’s surface. The needles used for this are short in length and thin in diameter because they don’t have to go all the way into the muscle layer. However, if a medicine needs to get to the muscle layer these thinner needles won’t be effective.

Needle Measurement

With needles, there are two important measurements to consider.

Gauge: The diameter, or thickness, of the needle. The higher the number, the finer or thinner the needle. For example, a 30-gauge needle is smaller than a 27-gauge needle.

Length: How long the needle is. This is measured in inches.

Injection Route

The gauge and length of the needle used for each medication is determined by the injection route.

Let’s compare injection options for IVF medications:

Subcutaneous injection (SC):

• Injected into the fatty tissue under the skin
• Usually given with 27-, 28-, or 30-gauge 0.5-inch needles

Intramuscular injection (IM)

• Injected directly into the muscle
• Usually given with 21-, 22-, or 25-gauge 1- or 1.5-inch needles

The needle for your IVF medication may come permanently affixed to the syringe, or you may be able to twist or push it on and off.

Your IVF medication may come pre-mixed or require mixing. Here are some examples and what to expect for the injections:

IVF medications That Are Pre-mixed

Your medication may come packaged from the manufacturer with the syringes and needles to be used for administration. These include:

• The Leuprolide acetate (Lupron) two-week kit. This comes in a pre-mixed multi-dose vial with syringes that have 28-gauge 0.5-inch needles affixed for SC injection.
• The Follistim and Gonal-f pens. These come with a supply of the 29-gauge 0.5-inch needles that must be twisted onto the pen before each use.
• The Gonal-f Multi-Dose vials. These come with syringes with 27-gauge 0.5-inch needles affixed.
• Several medications like ganirelix acetate and Ovidrel come in pre-filled, one-time use syringes with a 27-gauge 0.5-inch needle affixed.

IVF Medications That Require Mixing

There are other medications used in IVF cycles that require mixing a diluent with powdered medication to make a solution that can be drawn up and injected. These include Menopur, Novarel, Pregynl and human chorionic gonadotropin (hCG).

In this case, your nurse will order the appropriate syringes and needles for you to use. In general, you will use a 3cc syringe with a 22-gauge 1.5-inch needle to do the mixing and drawing-up, so you have both the length and diameter to make it easy to move liquid into and out of vials and syringes.

If you are then instructed to do an intramuscular injection, you can simply leave that same needle on for the injection. If you have been instructed to do a SC injection, you will carefully recap the needle, twist it off and replace with a 28- or 30-gauge 0.5-inch needle to do the injection.

Another option is a progesterone in oil for IM injection. This comes in a 10 ml multi-dose vial with needles and syringes ordered separately. Because the progesterone in oil is thicker than the water-based medications, some nurses order 18-gauge 1.5-inch needles to withdraw it from the vial. This needle can be intimidating due to its large size, but is only used to draw up the medication. You will use a 22-gauge 1- or 1.5-inch needle to do your injection.

Melissa Bell is a nurse manager at Reproductive Medicine Associates of New York. After graduating from Our Lady of the Lake College nursing school in Baton Rouge, Louisiana, she moved to New York and fell in love with the field of reproductive medicine. Melissa is passionate about helping individuals and families meet their family planning goals. She is currently working on research for the American Society of Reproductive Medicine and strives to be an influential leader for her nurses and an advocate for her patients. 

Selecting Syringes and Needles

Updated: December 30, 2021

Most of us can recognize a syringe, with a needle sticking out of a long plastic body. For many, it is a childhood horror that they can never forget! While your early years may have been spent dreading a needle, your teens or adulthood might require you to keep a supply of syringes ready to administer a doctor prescribed medication. When you start your own family, you may need a supply of needles for a family member to treat a medical condition. In this case, not only do you need to forget your old dread of this small medical device, but you will also need to know how to use it. Most importantly, you need to know that not all syringes are the same. There are different designs to meet different purposes.

Types of Syringes

Syringes are available in several different designs and varieties. Most are disposable, and many come with an attached needle or with no needle at all. You may select the size of the syringe by the volume of medication it holds. Below is an image depicting the parts of a syringe.

Selecting Syringes

Select syringes based upon the volume of medication prescribed and the desired pressure flow. Marked on the barrel is the amount, measured in centimeters (cc) or milliliters (mL). Both types of measurements are equivalent in volume. One cc is the same as a 1 mL. Large quantities of medication require larger syringe sizes. A need for lower pressure flows also requires a larger dimension. The use of a syringe for injections, with medical tubing or for irrigation are also factors in syringe selection. A prevalent type is the U-100 insulin syringe. It is a low volume syringe commonly used for diabetic medications. This syringe is for one-time use only and is thus a very low-cost syringe. Below is an infographic of a continuum depicting syringe sizes matched with corresponding usage--injections, medical tubing, or irrigation.

Syringe Tips

There are five basic types of syringe tips. The first and most popular is the Luer lock, which has a tip that allows the removal and reattachment of the needle. Disconnecting or attaching the needle is easy and quick. The needle hub locks to the syringe tip with a push and a twist. The twisting motion locks the needle hub into place. This twist mount helps secure the needle to the syringe for better safety and stability.

A slip tip syringe is also very common. The user may push the needle hub onto the syringe. Friction holds the needle hub in place on the syringe tip. There is no locking function like that found on the Luer lock.

Use eccentric tips when you need to administer a medication parallel to the skin of the patient. Use these tips when you want to inject into a surface vein without having the needle penetrate through both vascular walls. Aspiration of liquid medications is also effortless with this type of syringe.

Catheter tip syringes are useful for wound irrigation, for flushing medical tubing. Medical manufacturers make catheter tips with a tapered end to allow catheters to slip on and off of the tip.

The last type of tip is a syringe with a permanently attached needle. Frequently used for low-dose applications, these devices decrease medication waste. It is also disposable after use, making cleanup a snap. Tuberculin and insulin injections are popular with this syringe type.

Selecting Needles

Needles have a simple design with a hollow center, sharp point, and a hub that affixes to the syringe. Needle shafts come in varying lengths measured in inches. Guage sizes measure the thicknesses or diameter of the needle. Needle tips most often have a beveled tip to provide easier cutting or puncturing. Many needles come with a cap to protect the caregiver during the transition from package removal to needle use.

The criteria for selecting the right needle has three primary considerations--gauge, length, and use. Needle gauge measures the width or diameter of the needle. Length measures from the hub to the tip of the needle. Needle use refers to how deep the needle must traverse to reach the target injection area. These injection depths include intradermal (dermis injections), subcutaneous (subcutaneous tissue injections) and muscle (intramuscular injections.

Choosing the Needle Gauge

Selecting needles by gauge size occurs by considering skin or hide thickness and the depth of the injection. The needle gauge is a series of numbers in which the lower the number, the wider the diameter of the needle. The higher the gauge number, the smaller the needle width. On the other hand, smaller numbers denote a larger diameter or width. Larger diameter gauges have thicker needle walls and are stronger and more durable. They provide for more viscous medications and support denser skin penetration. Select a lower gauge number when using a high viscosity medication. Fine gauge needles (small diameter) offer less pain for the patient and accommodate low viscosity medications. Select a higher gauge number for these types of injections. The most common needle gauges are 26 and 27. This gauge range adapts to all three types of injections--intradermal, intramuscular and subcutaneous. See the Needle Gauge Continuum below for more details.

Choosing the Right Needle Length

Standard needles vary in length from 3/8 inch to 3-1/2 inch. The location of the administration determines the needle length required. Generally, the further the depth of the injection, the longer the needle. Intramuscular injections require extended needle lengths. Needle lengths for intramuscular injections are usually 7/8 to 1-1/2 inches. Subcutaneous injections call for a 1/2 to 5/8 inch needle. Intradermal injections require a needle length of 3/8 to 3/4 inch. The 1/2 and 5/8 inch needles are the two most common needle lengths and span both intradermal and subcutaneous injections. Below are three graphics to help select which is the best needle for your needs.

Purchasing Syringes and Needles

When you buy syringes, it is essential that you know which one you need. Are you using the syringe with needle for intradermal injections, intramuscular injections or subcutaneous injections? The needle gauge and needle length selection are different for each type of injection. Below is a quick list of the selection criteria used for purchasing a syringe and needle.

• The volume of medication to be administered determines syringe size.
• Type of needle hub used determines syringe hub. (Luer Lock, Slip Tip, Eccentric Tip or Catheter Tip)
• The viscosity of the medication determines needle gauge.
• Location of the injection determines needle gauge and needle length.

Make sure you know your needs before shopping!

Burt Cancaster writes articles for various publications usually related to health and medical topics. He loves skiing, mountain biking, hiking, racing, football, soccer, and travel.

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