Which of the following blood collection systems uses interchangeable multi-sample tubes that allow a phlebotomist to draw several blood specimens at the same time?
Evacuated tube system
Hypodermic needle and syringe system
Winged infusion set and syringe system
Lancet micro collection system
The Correct Answer is A
Choice A Reason:
The evacuated tube system is designed for the collection of multiple blood specimens using interchangeable tubes. This system utilizes a double-pointed needle, one end of which goes into the patient's vein and the other into a vacuum tube. As the blood is drawn, it automatically fills the tube until the vacuum is exhausted. The phlebotomist can then easily replace the filled tube with another without removing the needle from the patient's vein, allowing for multiple samples to be taken during a single venipuncture.
Choice B Reason:
The hypodermic needle and syringe system is typically used for manual blood draws when the evacuated tube system is not suitable, such as with small or fragile veins. This system does not use interchangeable tubes; instead, the blood is drawn into a syringe and then transferred into the appropriate tubes, which can be time-consuming and increase the risk of hemolysis or contamination.
Choice C Reason:
A winged infusion set, also known as a butterfly needle, is often used for patients with difficult veins. Like the hypodermic needle and syringe system, it does not inherently allow for the use of interchangeable multi-sample tubes. Blood is collected into a syringe or a single tube attached to the butterfly needle, and changing tubes usually requires a new puncture for each sample.
Choice D Reason:
The lancet microcollection system is used for capillary blood collection, typically from a fingerstick or heelstick. It is used for small volume samples and does not accommodate interchangeable multi-sample tubes. This method is commonly used for pediatric patients or when only a small amount of blood is needed.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is B
Explanation
Choice A reason:
Cleaning the site is a step that should be completed before anchoring the vein. The site should be cleaned with an antiseptic to reduce the risk of infection. Once the vein is anchored, cleaning the site again could displace the vein and compromise the anchoring.
Choice B reason:
After anchoring the vein, the phlebotomist should perform the procedure, which involves inserting the needle into the vein at the appropriate angle. Once the needle is in place and blood is seen in the tubing, the phlebotomist can proceed to collect the necessary amount of blood into the vacutainers or syringe.
Choice C reason:
Examining the needle is not the next step after anchoring the vein. The needle should be examined before the procedure begins to ensure it is the correct size and gauge for the venipuncture and that there are no defects.
Choice D reason:
Reapplying the tourniquet is not necessary at this point in the procedure. The tourniquet should already be in place to engorge the vein, making it easier to anchor and access. Reapplying it could cause discomfort or even disrupt the already anchored vein.
Correct Answer is C
Explanation
Choice A Reason:
Shaking the tubes vigorously can cause hemolysis, which is the rupture of red blood cells, leading to inaccurate test results. It is not recommended as it does not provide gentle mixing and can damage the blood cells.
Choice B Reason:
Moving the tubes in a figure-eight motion is not a standard practice for mixing blood samples. This method may not provide the consistent and gentle inversion needed to mix the anticoagulant with the blood effectively.
Choice C Reason:
Rolling the tubes between the palms of the hands 4 to 8 times after collection is the recommended method. This technique allows for gentle and thorough mixing of the blood with the anticoagulant, preventing clotting without causing hemolysis. The number of inversions ensures that the anticoagulant coats the inner surface of the tube and mixes with the blood, which is essential for accurate laboratory results.
Choice D Reason:
Passing the tubes from hand to hand is not an effective method for mixing blood samples. This action may not provide the necessary inversion and can lead to inadequate mixing, resulting in clotted specimens.
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