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 A
Explanation
Choice A Reason:
The chain of custody form is crucial in the context of a toxicology drug screen for legal purposes. It is a document that records the sequence of custody, control, transfer, analysis, and disposition of physical and electronic evidence. It is particularly important in legal cases where the results of the toxicology screen can be used as evidence in court. The chain of custody ensures that the sample has been handled properly and that the integrity of the sample has been maintained throughout the testing process.
Choice B Reason:
A requisition form is used to request a specific test or service. While it is an essential document in the process of ordering a toxicology drug screen, it does not serve the same purpose as the chain of custody in terms of legal proceedings. The requisition form typically includes patient information, the tests ordered, and the reason for the test, but it does not track the handling of the sample.
Choice C Reason:
An encounter form, also known as a superbill, is used in medical billing to capture the services provided during a patient's visit. It includes information about the patient's diagnosis, the procedures performed, and the codes for billing purposes. However, it is not specifically related to the legal aspects of a toxicology drug screen.
Choice D Reason:
The CMS 1500 form is the standard claim form used by healthcare providers to bill Medicare and Medicaid services. It is also used by some private insurers and managed care plans. Like the encounter form, it is related to billing and not to the legal chain of custody required for a toxicology drug screen.
Correct Answer is B
Explanation
Choice A reason:
Using a needle at a 45° angle does not typically result in collapsing the vein. A collapsed vein is more likely due to excessive vacuum pressure from the tube, a very small or fragile vein, or the tourniquet being too tight.
Choice B reason:
At a 45° angle, the needle is more likely to penetrate through the entire depth of the vein, especially if the vein is superficial. This can result in a failed venipuncture because the needle has entered and exited the vein, missing the opportunity to collect blood.
Choice C reason:
While a steep angle like 45° could cause the needle to miss the vein superficially, it is more likely that the needle would go through the vein at this angle rather than merely missing it superficially. A superficial miss is more likely with an angle that is too shallow.
Choice D reason:
Contacting the upper wall of the vein alone would not necessarily result in a failed venipuncture. However, at a 45° angle, the needle could easily slip through the vein entirely after contacting the upper wall, especially if the vein is not anchored well.
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
Report Wrong Answer on the Current Question
Do you disagree with the answer? If yes, what is your expected answer? Explain.
Kindly be descriptive with the issue you are facing.