All diabetics have to deal with it: taking blood samples and/or injecting insulin. Taking blood is done with lancets and injecting insulin with injection equipment such as pen needles (and sometimes with insulin syringes). These needles or lancets have a certain thickness and length. Of course the length matters, but it is easy to read. This is 'normally' stated in millimeters. The thickness of a needle, on the other hand, can sometimes raise some questions. The thickness of a needle is expressed in 'gauge' or 'G'. We will go into this in more detail in this article.
The unit of measurement 'gauge' dates back to the nineteenth century. At that time there was no universal unit to indicate the thickness of material. The British industry then adopted 'gauge'. A universal value for the thickness of material (steel and iron). And it is used to this day. The higher the G, the thinner the needle. A 16G needle is therefore (much) thicker than a 30G needle. And it is not the case that, for example, 15G is twice thicker than 30G.
Convert from gauge (G) to millimeter (mm)
With the table below you can easily convert the number of G's to millimeters.
| Number G | Amount millimetres (Mm) |
|---|---|
| 15G | 1,8 mm |
| 16G | 1,6 mm |
| 17G | 1,4 mm |
| 18G | 1,2 mm |
| 19G | 1,0 mm |
| 20G | 0,9 mm |
| 21G | 0,8 mm |
| 22G | 0,7 mm |
| 23G | 0,6 mm |
| 24G | 0,55 mm |
| 25G | 0,5 mm |
| 26G | 0,45 mm |
| 27G | 0,42 mm |
| 28G | 0,37 mm |
| 29G | 0,34 mm |
| 30G | 0,31 mm |
| 31G | 0,29 mm |
| 32G | 0,27 mm |
| 33G | 0,25 mm |
| 34G | 0,23 mm |
| 35G | 0,21 mm |
So much for the general explanation about gauge and converting it to millimeters. The story ends there for lancets. After all, a lancet is 'just' a needle. Another element is also important for injection material.
Inject insulin
Now if we look at pen needles to administer insulin, then the needle wall also matters. Or rather, the thickness of the needle wall. Fortunately, this needle wall has become increasingly thinner in recent years. This allows insulin to flow through faster and easier. BD calls this 'thin wall technology'. If there is more space inside the needle, insulin can be administered with less force and therefore with less pain in a shorter time. So in addition to the number G, the needle wall of injection material also matters.
Limit skin damage
The advice is always to use pen needles only once. The material is also designed for that. Pen needles are fragile. When a pen needle is used again, the point will no longer be as sharp and the lubricant will be gone. This makes it easier to damage the skin. In addition, the risk of infections also increases. The needles are no longer sterile after use! Insulin can also crystallize in the needle and block the needle, which may result in less or even no insulin coming out of the needle during the next injection. It is also important to regularly change the injection site so that the skin has time to recover.