Welcome curious traveler!
My name is Debra and I am medical laboratory technician - which is a fancy name for a lab tech. I have an Associates of Applied Science degree and have worked as a lab tech for the past 10 years. I want to share some of my knowledge with anyone who feels like reading it. This is my first ever blog post and I'm sad to say I don't have as many pictures in it as I would like. But hopefully you won't be too bored and I promise my next post will be full of color!
Most adults have had their blood drawn at some point in their life. Whether it was for general wellness testing or to assist the doctor in diagnosis, having your blood drawn can be a scary situation. I'm here to put your mind at ease by walking you through the entire process.
First off, all testing begins with your doctor's order - paper or electronic - that you present to a phlebotomist [fluh-bot-uh-mist]. A phlebotomist is a trained healthcare professional with comprehensive understanding of blood collection by venipuncture (using veins) and capillary technique (using fingertips or heels on infants) on all age groups.
After verifying the order, the phlebotomist will sit you down in a specialized chair that allows them to work easily and keep you comfortable (well as comfortable as you can be with someone stabbing your arm!). He/she will ask for your name and usually your date of birth to confirm you are the same person as the order is for.
Your phlebotomist should always put gloves on first; this is to protect you both.
Some will try to tell you that they can feel the vein better without the gloves and will put them for the actual stick but don’t let them! If they can’t feel it with a glove on they shouldn’t be sticking that vein.
The next step is to tie a tourniquet (which is basically a giant rubber band) around your upper arm, 3-5 inches above your elbow; the tourniquet needs to be tight enough to increase the blood pressure in the veins but not so tight that it cuts off the circulation. This helps the veins to “pop up” so they are easier to find and feel. You may be asked to make a fist (don’t pump it though! This can affect test results in a bad way!!) or rotate your wrist a certain way to help position the veins. They will then gently feel around for a vein. In the image below you can see the approximate location of veins as they cross the bend of the arm; the preferred vein is shown because it is usually the largest and has very few other structures around it (nerves, artery, tendon, etc.). Veins will feel squishy with a little bounce to them so you may notice the phlebotomist pressing up and down on the area multiple times.
Once they choose a vein, they will decide on the best needle for your vein. Needles come in many different sizes and forms; all needles used for blood collection in the U.S. are sterile and meant to be used one time only. Lots of factors must be considered when choosing a needle collection device. How many tubes must be filled? Is the vein really close to the surface of the skin or is it a bit deeper? This is a 21 gauge needle from Bectin Dickinson (BD); it features a sterile needle on one end, a safety device, and a rubber covered needle.
For this style, you first remove the white cap and screw this into a plastic hub (see picture below); when ready to stick the vein, the green cap is removed to expose the needle. The purple safety device is quickly activated after removal from the vein with one hand and clicked into place over the needle. The entire device is then discarded. The safety device is there to protect everyone as the device is discarded and to prevent the reuse of the needle.
Have you ever heard of a “butterfly” needle? Did you know they are not always the smallest needle?
The butterfly collection set is used when sticking a vein on the top of the hand, children, and difficult veins and sometimes when collecting blood into special tubes. The needle size can be the same as a “straight” needle (21-23 gauges).
Butterfly needles have their place in a blood draw but should not be used just because you think it will hurt less.
It is always our goal to make this as painless as possible – trust our experience and let us do our job. We understand that pain is objective, meaning everyone experiences it differently and you want this to be as painless as possible but you can actually make us really nervous when you start saying you are hard to stick or you will only let us do it with a butterfly. We’ve been trained and most of us have our routine down, so when you start messing with that routine it can fluster some of us.
Unless you have a valid reason (physician’s recommendation) you shouldn’t be picking what we use to draw your blood. You wouldn’t walk in and tell a surgeon what tools to use would you? It’s the same thing – we are the expert, not you!
After choosing the needle, your skin will need to be disinfected to prevent any infectious bacteria/virus/fungus from entering your body when the needle goes in. We usually use an alcohol pad but some tests require something different be used. The skin should be allowed to dry naturally – never fan it or blow on it – to keep the area sterile. We will remove the needle cap and inspect the needle’s tip to make sure the hole is pointing upwards. They will anchor the vein below where they wish to stick so that it lessens the chance of the vein rolling. A properly inserted needle is shown in figure A below. The other images show what may be happening when there is no blood flow after inserting the needle.
If a vein rolls off to the side – it is usually a bad idea to try and chase it down. In rare cases we may attempt to take one more jab towards it – but it must done with caution and only by moving the needle as little as possible. Veins tend to roll away when the needle hits to the side instead of the middle of the vein. Think of it as if you were trying to stab a hot dog with a knife – the curve of the hot dog sides will deflect the knife whereas hitting it dead center catches the flattest point of the cylinder. Most of the time when a phlebotomist or lab tech tells you that you have veins that roll it's an excuse; when properly anchored and stabbed (sorry) the vein should be easily punctured.
After insertion, they will place a tube inside the hub and push on it to pierce the cap; blood will automatically flow into the tube because they have been filled with air, creating a vacuum.
Once blood is flowing into the tube they should release the tourniquet to prevent bruising or release of other fluids from the surrounding tissue. If there is no blood flow – the phlebotomist should only ever move the needle a little more forwards or pull it out a little bit while adjusting the angle. They should NEVER go fishing for the vein and move the needle around and around – we are trained to never do this! If they start doing this and you are uncomfortable tell them to stop immediately.
When all tubes are filled, in a single swift motion they should pull the needle out with one hand, engage the safety device (takes quick press, usually with thumb), and place a cotton ball over your new wound. They should never place the cotton ball on top of the needle and press down while pulling the needle out – this puts them at risk for getting hurt by the needle. The needle will then be placed in a special plastic container called a "sharps" box; Sharps waste is classified as biohazardous and must be carefully handled by trained personnel only. "Strict hospital protocols and government regulations ensure that hospital workers handle sharps waste safely and dispose of it effectively."
They may ask you to hold pressure on it while they prepare a band aid/tape; pressure should be applied for at least 5 minutes to ensure the bleeding has stopped. If pressure is not held, the vein will continue to bleed for about 15 minutes and the blood could gather under the skin and leave a nasty bruise.
So there you have it. Hopefully you’ve learned a little something today!
My next entry will discuss common reasons you have to have your bloodwork repeated.
Other Resources:
Basic Principles of Phlebotomy
Vacuum Blood Collection by Terry Kotrla
OSHA
What is a phlebotomist?
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