Which of the following tube additives promotes clot formation?
Heparin
Oxalate
Citrate
Silica
The Correct Answer is D
Choice A reason:
Heparin is an anticoagulant, not a clot activator. It works by inhibiting thrombin and preventing the conversion of fibrinogen to fibrin, thus preventing clot formation. It is commonly found in green-top tubes and is suitable for collecting plasma samples for tests like electrolyte levels and coagulation studies.
Choice B reason:
Oxalate is also an anticoagulant that prevents clotting by precipitating calcium. It is not used to promote clot formation but rather to maintain a blood sample in a non-coagulated state for various tests.
Choice C reason:
Citrate functions similarly to heparin and oxalate as an anticoagulant. It chelates calcium ions in the blood, inhibiting the coagulation process. Citrate is often used in blue-top tubes and is ideal for collecting plasma samples for coagulation studies.
Choice D reason:
Silica is a clot activator. It is commonly used in serum separator tubes (SSTs) with a gold or red speckled top. The silica particles provide a surface for the rapid formation of the clot, allowing for the separation of serum from the blood cells. This is essential when serum is needed for testing.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is B
Explanation
Choice A reason:
A hair cap is used to prevent contamination from the hair, but it is not specifically designed to protect against body fluid splashes. While it is a part of personal protective equipment (PPE), it does not provide coverage for the areas most likely to be exposed to splashes during phlebotomy procedures.
Choice B reason:
A gown is the appropriate choice for protection against body fluid splashes. It covers a significant portion of the body and is designed to prevent fluids from reaching the phlebotomist's skin or undergarments, which is essential when there is a risk of splashes during procedures like venipuncture.
Choice C reason:
Shoe covers protect the feet from contamination, but they are not typically necessary for phlebotomy unless there is a significant risk of large fluid spills on the floor. They are more commonly used in operating rooms or during the cleaning of large spills.
Choice D reason:
Sterile gloves are a standard requirement for phlebotomy to maintain aseptic technique and prevent contamination. However, gloves alone do not provide sufficient protection against body fluid splashes that may reach other parts of the body.
Correct Answer is C
Explanation
Choice A Reason:
Sterile water is not an antiseptic; it does not contain antimicrobial agents. While it can be used to rinse a site, it will not disinfect the area before a venipuncture procedure. Therefore, it is not an appropriate substitute for alcohol in this context.
Choice B Reason:
Antiseptic foam may contain alcohol or other disinfectants. If it is alcohol-free, it could be a suitable alternative. However, without specific information about the ingredients, it cannot be assumed to be an appropriate choice for a patient allergic to alcohol.
Choice C Reason:
Chlorhexidine is a commonly used antiseptic for skin preparation before medical procedures, including venipuncture. It is effective against a broad spectrum of bacteria and is an appropriate alternative for patients who have an allergy to alcohol-based antiseptics.
Choice D Reason:
Saline solution is not an antiseptic. It is a sterile solution of sodium chloride in water and does not have antimicrobial properties. Like sterile water, it is not suitable for disinfecting the venipuncture site.
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