Hemoconcentration of a venous blood sample is most often caused when:
The site is prepped with povidone iodine.
The tourniquet is in place for more than 2 minutes.
The specimen is not refrigerated within 30 minutes.
The needle is removed before the tourniquet.
The Correct Answer is B
Choice A Reason:
Prepping the site with povidone iodine is not typically associated with hemoconcentration. Povidone iodine is used as an antiseptic to clean the skin before venipuncture to prevent infection. While it's important to allow it to dry to avoid sample contamination, it does not cause hemoconcentration.
Choice B Reason:
Leaving the tourniquet in place for more than 2 minutes can lead to hemoconcentration. A tourniquet is applied to engorge the veins, making them easier to puncture. However, prolonged application can result in fluid being forced out of the vein into the tissue, increasing the concentration of cells and larger molecules in the blood. This can affect certain laboratory test results by artificially increasing the levels of cellular components.
Choice C Reason:
Not refrigerating the specimen within 30 minutes does not cause hemoconcentration. However, it can affect the stability of certain analytes in the blood sample. Refrigeration is necessary for preserving the integrity of certain components of the blood until analysis, but it is unrelated to the concentration of cells within the sample at the time of collection.
Choice D Reason:
Removing the needle before the tourniquet is released does not cause hemoconcentration. This action might lead to other complications, such as hematoma formation, but it does not affect the concentration of cellular elements in the collected sample.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is D
Explanation
Choice A Reason:
Inverting the tube 5 to 7 times may not be sufficient to mix the blood thoroughly with the EDTA. This could lead to partial clotting and potentially inaccurate test results. The EDTA anticoagulant works by binding calcium ions, which are necessary for blood clotting. Without adequate mixing, the EDTA may not be evenly distributed, leaving some areas of the blood sample able to clot.
Choice B Reason:
Inverting the tube only 2 to 4 times is inadequate for proper mixing. This minimal agitation would likely result in clot formation because the anticoagulant would not be sufficiently mixed with the blood. Clots can interfere with the accuracy of hematological tests by trapping cells and altering the specimen's composition.
Choice C Reason:
Inverting the tube 1 to 3 times is clearly insufficient and would almost certainly lead to clotting. The purpose of inverting the tube is to ensure that the EDTA coats all the blood cells, preventing coagulation. Such a low number of inversions would not allow for the anticoagulant to perform its function effectively.
Choice D Reason:
Inverting the tube 8 to 10 times is the recommended practice. This number of inversions ensures that the blood is fully mixed with the EDTA, preventing clot formation and preserving the integrity of the sample for accurate laboratory analysis. It is important to perform these inversions gently to avoid hemolysis, which can also affect test results. Hemolysis occurs when red blood cells are damaged and their contents leak out, which can happen if the blood is shaken too vigorously.
Correct Answer is D
Explanation
Choice A reason:
While maintaining compliance with Clinical Laboratory Improvement Amendments (CLIA) standards is important, it is not the primary reason for explaining the venipuncture procedure to the patient. CLIA standards primarily deal with laboratory testing and do not specifically require the explanation of procedures to patients.
Choice B reason:
Evaluating the patient's understanding is a beneficial practice as it ensures that the patient is informed and can participate in their own care. However, it is not the primary legal or ethical requirement for explaining the procedure.
Choice C reason:
Maintaining compliance with Occupational Safety and Health Administration (OSHA) standards is crucial for ensuring the safety of both the healthcare provider and the patient. OSHA standards require that certain safety protocols be followed, but they do not specifically mandate that the procedure be explained to the patient for the purpose of obtaining consent.
Choice D reason:
Obtaining the patient's consent is the primary reason a phlebotomist should explain the procedure prior to venipuncture. Informed consent is a fundamental ethical and legal principle in healthcare. It involves informing the patient about the procedure, its risks, benefits, and alternatives, and ensuring that the patient understands this information before agreeing to proceed. This process respects the patient's autonomy and right to make decisions about their own healthcare.
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