Syringes are designed to hold an accurate volume of fluid, and have markings to help the user identify when the correct volume is in the syringe. Healthcare professionals use syringes often, and so know the knack to reading them. For everyone else, though, reading syringes is an acquired skill. Small syringes, by necessity, have tiny markings, and so extra care must be taken before dispensing the liquid.
Turn the syringe vertically so that the numbers are the right way up. On a syringe, the measurements start from the bottom, which is the end where a needle can fit in, and then increase towards the top, which is the end that you pull and push to fill and empty the liquid. Some syringes have the numbers printed so they can be read by a person looking from the needle end, and some have the numbers printed so a person looking down from the plunger end can read them.
Match up the longer lines on the syringe with the printed numbers. In a 1 ml syringe, the printed numbers normally represent 0.1 ml intervals. The syringe should therefore have a long line at the needle end marked with a 0.1, and a long line at the plunger end marked with a 1.0. In between, there are other long lines representing 0.2 ml and so on.
Look at the smaller lines in between the 0.1 ml intervals. As the syringe is so small, these markings cannot fit little numbers in them. Instead, there are four little lines in between the long lines, splitting the 0.1 ml intervals into five portions. Each portion represents a fifth of a 0.1 ml, which is 0.02 ml. For example, if you need a dose of 0.14 ml in the syringe, the volume should be over the first long line and up to the second little line.
- Always ask a healthcare professional if you are unsure about correct medicine doses. An overdose or an underdose can be dangerous in many cases, and it is the job of the doctor or nurse to properly explain the procedure to you.
- An easy way to prevent overdose is to only fill the syringe up to the desired volume, so that you cannot accidentally press the plunger too hard and dispense too much fluid.
- Be very careful not to read insulin syringes in this way, as they are marked with the amounts of insulin units, instead of insulin volume. A 100 unit insulin syringe, according to the NHS, holds only 1 ml of insulin.
- Syringes are scientifically calibrated to hold accurate volumes of liquid, but this only applies to the markings, so you should always measure to the markings, and not guess at smaller increments in between markings.
- Filling a syringe properly without getting air or other substances into the liquid requires a specific technique, so you should also know how to do this.
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