Which of the following is the correct order of collection?
Citrate, heparin, EDTA, fluoride
Citrate, EDTA, heparin, fluoride
Fluoride, EDTA, heparin, citrate
Fluoride, heparin, EDTA, citrate
The Correct Answer is B
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.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is C
Explanation
Choice A reason:
A sodium level test is important for managing and monitoring a patient's electrolyte balance, particularly in critical care settings. However, a DNR order indicates that the patient has chosen not to undergo CPR, not necessarily that their condition is the most critical at the moment. Therefore, while important, it may not be the most urgent sample to process.
Choice B reason:
Postoperative monitoring of hemoglobin and hematocrit levels is crucial for detecting possible hemorrhage and ensuring proper recovery. However, unless there is an immediate concern for acute blood loss or other complications, these tests may not be as urgent as a stat test from the emergency room.
Choice C reason:
A stat potassium level is typically ordered when there is an urgent need to assess a patient's potassium due to conditions that can rapidly affect heart rhythm and muscle function. In the emergency room setting, where patients often present with acute and life-threatening conditions, stat tests are prioritized to provide rapid results that can influence immediate clinical decisions.
Choice D reason:
Peak antibiotic levels are measured to ensure therapeutic efficacy and to avoid toxicity. While important for managing a patient's treatment, especially for those who are NPO (nothing by mouth), it may not be as time-sensitive as a stat test required for an acute emergency.
Correct Answer is B
Explanation
Choice A reason:
The date of birth is a common identifier, but it is not unique to an individual, as multiple patients may share the same birth date. While it is useful in conjunction with other identifiers, on its own, it does not provide a definitive identification.
Choice B reason:
The record number, often referred to as the medical record number, is a unique identifier assigned to each patient within a healthcare system. It is used to track patient information across different visits and services, making it the most reliable standalone identifier if the patient's name is not available.
Choice C reason:
An address can change over time and may not be unique, especially in large apartment buildings or for patients who are homeless or transient. It is also not specific enough to reliably identify a patient, as multiple individuals can reside at the same address.
Choice D reason:
The social security number is a unique identifier, but due to privacy concerns and the risk of identity theft, it is not the preferred method for patient identification in healthcare settings. Additionally, not all patients may have a social security number, such as non-residents or newborns.
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