The syringe method has long been used to draw blood for testing. It is unique in its own way when compared to the other methods for drawing blood. It is simple and straightforward.
If you can get a good handle of the syringe method you will no doubt be good at drawing blood. Being able to maneuver it well will sharpen your skills and make using the other methods easier.
While it is not the most common method used, you will use it many times for the elderly, children and difficult patients.
What Are the Advantages of the Syringe Method?
There are many pros of using the syringe and needle to do blood tests. They include:
- Different sizes. There is a 10, 5, or 3 ml that can be used. Based on the amount of blood needed decide on which one to use.
- Syringe can be attached to a butterfly needle for kids, elderly or difficult veins.
- Can be attached to needles with safety mechanism.
- Most suitable for thin, small, fragile and rolling veins.
- Blood appears in the hub when vein has been entered.
- You can control the pressure and speed at which blood is drawn. That is important for fragile veins.
- Can prevent or lessen trauma to small/fragile veins in the elderly.
- Can be maneuvered.
What Are the Disadvantages Of the Syringe Method?
The cons of the syringe method are as follows:
- Chances of needlestick injuries are increased.
- Limited amount of blood.
- Can be labor intensive for large volume draws.
- Can cause hemolysis when pulling back too hard or fast on plunger. Also, when filling tubes incorrectly.
- Transfer of blood into tubes.
- 10 mil plungers are hard to pull.
- Time consuming in transferring blood from one tube to another.
- Platelet clumps form if blood is not transferred immediately.
- Can be difficult to maneuver when the draw is from a difficult position (area of location of the vein or the position of the patient).
Why Is the Phlebotomy Syringe Method Used?
The syringe and needle method is used for small, rolling, fragile, hand and other difficult veins. Patients with those veins include persons from all ages. So, children, some adults, elderly and critical care patients.
The Evacuated Tube System is used for good veins. Most people have good veins but there are times when a person has small or thin veins. Elderly veins are usually fragile and rolling, and so, in cases like that you would use a syringe and needle to draw blood.
The syringe method is safer for those veins because you can control the pressure and speed at which blood is drawn. Also, it reduces the stress exerted on those veins and prevents vascular collapse.
In some instances, a syringe can be used with a butterfly needle to draw blood, especially, when the patient is in a position that is difficult to control a syringe and needle. The extended length of the butterfly will make it easier to collect the blood.
Cases like that can include drawing blood from some children, critical care patients, patients at hospitals and sometimes, hand veins.
How Long Should Blood Stay in Syringe?
As soon as the desired amount of blood has been drawn from the vein transfer the blood from the syringe into the tube or tubes. The blood will clot if it stays too long in the syringe.
Also, be mindful of the time you are taking to draw blood. I know drawing blood from difficult veins or patients can take a little while but it is important that you don’t take too long. Platelet clumps can form when you take long and will cause erroneous results in some testing.
Quickly transfer blood into the respective tubes following the order of draw. Remember to invert tubes as necessary.
How Do You Transfer Blood From a Syringe To a Tube?
After collecting the desired amount of blood remove the needle from the syringe and dispose it in a sharps container. Attach a safety transfer device to the syringe then pierce the tube closure and allow the vacuum in the tube to draw the proper volume of blood from the syringe.
Do Not push the plunger of the syringe. Doing so will hemolyze the sample. Just allow the vacuum to draw the blood.
If the blood has clotted in the syringe when filling red tops Do Not push the plunger to force the blood out through the needle. Instead, remove the transfer device and the tube stopper and deliver the blood to the tube slowly to avoid hemolyzing the sample.
If for some reason the specimen is hemolyzed you may have to redraw the blood for best testing and results.
If a safety transfer device is not available put the tube or tubes in a rack and using one hand pierce the tube stopper with the needle. Do Not handhold the tube while you are pushing the needle through the stopper. Once penetrated allow the vacuum in the tube to draw the blood.
What is the Order of Draw When Transferring Blood From a Syringe?
It is important that you follow the order of draw when transferring blood into tubes. As color coding and tube additives may vary, verify recommendations with manufacturers or local laboratories. Below is a simplified order of draw:
- Blood culture bottle (yellow-black stripped tubes)
- Non-additive tube
- Coagulation tube (light blue top)
- Clot activator (red top)
- Serum separator tube (red-grey tiger top or gold)
- Sodium heparin (dark green top)
- PST (light green top)
- EDTA (purple top)
- Blood tube (pale yellow top)
- Oxalate/fluoride (light grey top)
Of course, you are not going to have to fill all those tubes in one draw. It may just be two or three tubes you have. But in general, remember, blue is before red, red is before purple and purple is before grey. Most times, those colors are the most common ones used.
Other methods of venipuncture? go read about the Evacuated Tube System here.