THE MATERIALS NEEDED FOR A VENIPUNCTURE

The sampling centers usually use sole utilization barrels or a barrel endowed with a quick trigger, which is easy to handle with one hand only.

The quick trigger barrel is used by countless health facilities, as it is reusable thanks to its needle trigger and to its safety during handling. It was designed to minimize the accidental injury risks during blood sampling.

‘Caliber’ actually represents the needle diameter. The finer a needle diameter, the larger the number of gauges. Vice-versa, the bigger the needle diameter (in gauges), the smaller that needle caliber. Let us take for instance a 22 G caliber needle : the needle diameter is smaller than the 21 G caliber needle.

There are several needle calibers available and used by registered nurses and by other professionals authorized to perform blood sampling operations. The blood sampling responsible nurses may select both the caliber and the length of a needle, subject to their needs.

NEEDLE CALIBERS THAT MAY BE USED FOR BLOOD SAMPLING

• 21 G needle x 1" (0.8 x 25 mm). The color of the protective cap is green.
• 22 G needle x 1" (0.7 x 25 mm). The color of the protective cap is black.
• 21 G needle x 1" 1/4 (1.25 inch long). The color of the protective cap is green.
• 21 G needle x 1" 1/4 (1.25 inch long). The color of the protective cap is black.

There are also some other types of needles that can be a good choice for difficult venous sampling,

for instance the needles endowed with a device with little wings and an activating button (commonly called ‘butterfly needle’).

The tourniquet is used as a device meant to stop a hemorrhage on a part of the human body. As regards blood sampling, it however has got a really specific function.

The tourniquet used for blood sampling is first of all squeezed all around the patient’s forearm, approximately 10 cm above the place where the venous puncture is to be made. The blood sampling professional can then test-feel, touch and choose the right place for blood sampling.

The role of the tourniquet is to make a patient’s veins swallow up in his/her arm, by exerting a pressure on a part of the human body in order to reduce its volume. The tourniquet is only allowed to be applied on a patient’s arm between the shoulder and the wrist.

There are several kinds of tubes than may be used for taking blood samples : either made of glass (the most commonly used ones) or of polymer (unbreakable). These tubes protect from blood spilling in case of breaking.

EXAMPLES OF TUBES

• Green and red hemoculture bottles
• Serum red tubes
• Citrate royal blue tubes
• EDTA lavender tubes
• SST yellow tubes with a gel
• Sodium fluoride grey tubes
• Forest green tubes with heparin

All the blood tubes are for biological tests that enable accurate laboratory results. The procedure linked to tube order and reversal is to be complied with in order to provide accurate blood tests.

In case of the laboratory tests, a pre-test process, adequate transportation and sample processing need to be observed in order to issue reliable results for physicians, so that they can set up a correct medical diagnosis.

THE ANTISEPTICS

The 70 % isopropyl alcohol-saturated antiseptic swabs are regularly used to disinfect the place where the venous puncture is to take place. The health professional rubs the area with the alcohol-imbibed swab, making circular moves from the outside towards the inside, being aware that he/she must finish disinfecting in the middle of the blood sampling area.

NON STERILE OR COTTON WOOL COMPRESSES

A compress is composed of a woven hydrophilic fabric and sometimes of woven cotton.

Within blood sampling, the compresses role is to absorb the blood ; they thus do not need to be sterile. The care taking nurse uses the compress to exert pressure once the needle is taken out of the vein.