A phlebotomist needs to collect a PT (Prothrombin Time) from a patient with a difficult vein. Which of the following is the best tube for the draw?
Light green
Lavender
Royal blue
Light blue
The Correct Answer is D
Choice A reason:
The light green tube typically contains lithium heparin and is used for plasma determinations in chemistry. It is not suitable for coagulation studies, such as PT, because heparin is an anticoagulant that would interfere with the test results.
Choice B reason:
The lavender tube contains EDTA, which is an anticoagulant that binds calcium. While it is commonly used for complete blood counts (CBC) and other hematology tests, it is not appropriate for coagulation studies because the binding of calcium would affect the clotting process required for a PT test.
Choice C reason:
The royal blue tube can come with different additives or be additive-free, depending on the color of the closure. It is primarily used for trace element testing, toxicology, and nutrient determinations. The additives in a royal blue tube could potentially contaminate the sample and interfere with the PT test.
Choice D reason:
The light blue tube contains sodium citrate, which is the appropriate anticoagulant for coagulation studies like PT. Sodium citrate works by binding calcium in the blood, preventing clotting. The PT test measures the time it takes for a clot to form after re-calcification, making the light blue tube the correct choice for this test.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is D
Explanation
Choice A reason:
Collecting stool directly into a sterile container is not related to providing a sputum specimen. Stool samples are collected for different types of tests, such as fecal occult blood tests or microbiological cultures, and are not used for respiratory assessments.
Choice B reason:
Discarding the first urine of the day and collecting for 24 hours is a procedure for a 24-hour urine collection test, which is used to assess kidney function and other conditions. This process is unrelated to sputum specimen collection, which is used to evaluate respiratory infections or conditions.
Choice C reason:
Aggressively swabbing the inside of the cheek is a method used to collect cells for DNA testing or to check for oral infections. This action does not pertain to sputum collection, which requires a sample from the lower respiratory tract.
Choice D reason:
Taking a deep breath and then expectorating (coughing up and spitting out) is the correct method for providing a sputum specimen. This technique ensures that the sputum comes from deep within the lungs, which is necessary for accurate analysis of respiratory pathogens or cells.
Correct Answer is D
Explanation
Choice A reason:
Covering a quarter of the slide is not an acceptable criterion for the quality of a peripheral blood smear. The smear should be spread across the slide in a manner that allows for proper examination under a microscope, and covering only a quarter of the slide would not provide enough area for an adequate assessment.
Choice B reason:
Having a well-defined edge is not specifically indicative of the quality of a peripheral blood smear. While the edges should be clean to allow for clear viewing of the cells at the margins, the quality is more accurately determined by the distribution and integrity of the cells on the slide.
Choice C reason:
Covering the entire slide is also not a criterion for a quality peripheral blood smear. In fact, if the blood covers the entire slide, it may be too thick to allow for proper cell differentiation and examination. A proper smear should have a gradient of cell distribution, ending with a feathered edge.
Choice D reason:
A feathered edge is the correct criterion for a quality peripheral blood smear. The feathered edge is the thinnest part of the smear and is where the cells are ideally distributed in a single layer, which is optimal for microscopic examination. This allows for the best visualization of cell morphology and is essential for accurate diagnosis.
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