According to the CLSI standard, a phlebotomist must attempt to locate which of the following veins on both arms before considering other veins?
Median cubital vein
Basilic vein
Cephalic vein
Veins on the underside of the wrist
The Correct Answer is A
Choice A Reason:
The median cubital vein is often the first choice for venipuncture due to its size and accessibility. It is located in the antecubital fossa and is usually well anchored by surrounding tissues, which makes it less likely to roll during needle insertion. This vein is also less painful for patients when punctured due to its location and the type of surrounding tissue.
Choice B Reason:
The basilic vein is another option for venipuncture, but it is not typically the first choice. It is located on the medial aspect (inner side) of the arm and is more prone to rolling and injury because it is not as well anchored as the median cubital vein. Additionally, the basilic vein is located near nerves and arteries, which increases the risk of complications during venipuncture.
Choice C Reason:
The cephalic vein runs along the lateral aspect (outer side) of the arm and can be used for venipuncture. However, it is often more difficult to locate and has a tendency to roll, which can make venipuncture more challenging. It is usually considered after the median cubital vein.
Choice D Reason:
Veins on the underside of the wrist should generally be avoided for routine venipuncture because they are often smaller, can be more painful due to the proximity to nerves and tendons, and have a higher risk of complications. These veins are considered only when other sites are not available or are unsuitable for venipuncture.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is D
Explanation
Choice A reason:
The Apgar score is a quick test performed on a newborn at 1 and 5 minutes after birth. The 1-minute score determines how well the baby tolerated the birthing process. The 5-minute score tells the healthcare provider how well the baby is doing outside the mother's womb. While it is an important indicator of a newborn's health, it does not directly influence the calculation of total blood volume.
Choice B reason:
Height is a measure of the length of a person's body. In the context of a 2-day-old infant, height is not a practical or necessary measurement for determining blood volume. Blood volume is more closely related to weight than to height, especially in the case of infants.
Choice C reason:
Head circumference is a measurement of the size of a child's head and is used to monitor brain growth. While it can provide valuable information about a child's development, it is not used to calculate blood volume. The total blood volume of an infant is not determined by the size of the head but rather by the overall weight.
Choice D reason:
Weight is the correct factor to consider when calculating total blood volume for a full-term, 2-day-old infant. The standard formula to estimate an infant's total blood volume is approximately 80 {mL/kg} of body weight. Therefore, knowing the infant's weight in kilograms is essential for this calculation.
Correct Answer is B
Explanation
Choice A reason:
The order of citrate, heparin, EDTA, and fluoride is not the correct sequence for blood collection. The correct order is essential to prevent cross-contamination of additives between tubes, which could interfere with test results. Citrate tubes should be drawn first to ensure that the blood does not clot prematurely, but heparin should not follow immediately after citrate.
Choice B reason:
Citrate tubes, which contain sodium citrate, are used for coagulation tests and must be drawn first to ensure the proper blood-to-additive ratio. EDTA tubes are drawn next because EDTA binds calcium and prevents clotting, making it ideal for complete blood counts and other hematology studies. Heparin tubes, which prevent clotting by inhibiting thrombin and thromboplastin, are drawn after EDTA. Lastly, fluoride tubes, which contain a glycolysis inhibitor, are drawn to preserve glucose levels and are typically used for glucose and lactate testing.
Choice C reason:
Starting with fluoride is not recommended as it could lead to contamination of the EDTA and heparin tubes with fluoride, which could affect the results of certain tests, such as calcium determinations in heparin tubes. The order of draw is designed to minimize such risks.
Choice D reason:
This sequence is incorrect because fluoride tubes are not drawn before EDTA and heparin tubes. The presence of fluoride could potentially contaminate the subsequent tubes and alter the results of the tests that require heparin or EDTA as an anticoagulant.
In phlebotomy, following the correct order of draw is crucial. The order is established based on the type of additive in each tube and its potential to interfere with tests conducted in subsequent tubes. The standard order is: blood cultures, citrate tubes, serum tubes with or without clot activator and gel, heparin tubes with or without gel, EDTA tubes, and lastly, fluoride tubes. This sequence helps prevent cross-contamination and ensures the accuracy of laboratory results, which are critical for patient diagnosis and treatment.
Whether you are a student looking to ace your exams or a practicing nurse seeking to enhance your expertise , our nursing education contents will empower you with the confidence and competence to make a difference in the lives of patients and become a respected leader in the healthcare field.
Visit Naxlex, invest in your future and unlock endless possibilities with our unparalleled nursing education contents today