Nursing practice questions with comprehensive rationales
NurseDive Free Nursing Practice Question
How many times should an EDTA tube be inverted after blood collection?
A. 5 to 7
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.
B. 2 to 4
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.
C. 1 to 3
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.
D. 8 to 10
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.
This question is an excerpt from Nurse Dive's nursing test bank - Phlebotomy Certification Proctored Exam 130. Take the full exam now
Full 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.
Similar Questions
Which of the following is the correct angle of insertion when performing venipuncture using the evacuated tube method?
A. 50°
An angle of 50° is too steep for venipuncture and increases the risk of going through the vein and causing injury to structures beneath it. A steeper angle can also make it more difficult to control the depth of the needle, leading to an increased chance of puncturing the posterior wall of the vein.
B. 30°
An angle of 30° is the recommended angle for venipuncture as it allows for a smooth entry into the vein without going too deep. This angle helps to ensure that the needle enters the vein in a controlled manner and minimizes the risk of injury to the patient. It also provides a good balance between ease of entry and control over the needle's depth.
C. 90°
An angle of 90° is not recommended for venipuncture because it is perpendicular to the skin, which greatly increases the risk of passing through the vein entirely and causing injury. This angle does not allow for any control over the depth of the needle and is likely to cause discomfort or pain to the patient.
D. 75°
An angle of 75° is also too steep for safe venipuncture. Similar to a 50° angle, it increases the risk of penetrating the posterior wall of the vein and potentially damaging surrounding tissues or arteries. It is important to use a lower angle to ensure the safety and comfort of the patient during the procedure.
Full Explanation
Choice A Reason:
An angle of 50° is too steep for venipuncture and increases the risk of going through the vein and causing injury to structures beneath it. A steeper angle can also make it more difficult to control the depth of the needle, leading to an increased chance of puncturing the posterior wall of the vein.
Choice B Reason:
An angle of 30° is the recommended angle for venipuncture as it allows for a smooth entry into the vein without going too deep. This angle helps to ensure that the needle enters the vein in a controlled manner and minimizes the risk of injury to the patient. It also provides a good balance between ease of entry and control over the needle's depth.
Choice C Reason:
An angle of 90° is not recommended for venipuncture because it is perpendicular to the skin, which greatly increases the risk of passing through the vein entirely and causing injury. This angle does not allow for any control over the depth of the needle and is likely to cause discomfort or pain to the patient.
Choice D Reason:
An angle of 75° is also too steep for safe venipuncture. Similar to a 50° angle, it increases the risk of penetrating the posterior wall of the vein and potentially damaging surrounding tissues or arteries. It is important to use a lower angle to ensure the safety and comfort of the patient during the procedure.
A phlebotomist should recognize that the Clinical and Laboratory Standards Institute (CLSI) recommends that a heel stick depth should not penetrate deeper than which of the following depths for an infant patient?
A. 2.0 mm
The recommended heel stick depth of 2.0 mm is based on the need to minimize the risk of injury to the infant. Penetrating deeper than this can increase the likelihood of hitting bone, which in infants can be as close as 2.0 mm under the skin of the plantar surface of the heel. This depth is sufficient to obtain a blood sample without risking injury to deeper tissues or bone.
B. 2.5 mm
A depth of 2.5 mm may be too deep for some infants, especially preterm or very small infants, where the calcaneus (heel bone) is closer to the surface. While this depth might still be safe for some infants, it does not provide the same margin of safety as the 2.0 mm recommendation and could potentially lead to bone puncture or other injuries.
C. 3.0 mm
A depth of 3.0 mm significantly increases the risk of bone puncture, especially in infants with less subcutaneous fat or in those who are preterm. This depth could easily breach the protective layer of skin and subcutaneous tissue, leading to a higher risk of osteomyelitis, an infection of the bone, which can be a serious complication in infants.
D. 3.5 mm
A depth of 3.5 mm is considered too deep for a heel stick procedure and is likely to cause injury to the infant. This depth would almost certainly penetrate the bone in most infants, leading to severe pain, potential for infection, and other complications. It is well beyond the safe range recommended by CLSI and should be avoided.
Full Explanation
Choice A Reason:
The recommended heel stick depth of 2.0 mm is based on the need to minimize the risk of injury to the infant. Penetrating deeper than this can increase the likelihood of hitting bone, which in infants can be as close as 2.0 mm under the skin of the plantar surface of the heel. This depth is sufficient to obtain a blood sample without risking injury to deeper tissues or bone.
Choice B Reason:
A depth of 2.5 mm may be too deep for some infants, especially preterm or very small infants, where the calcaneus (heel bone) is closer to the surface. While this depth might still be safe for some infants, it does not provide the same margin of safety as the 2.0 mm recommendation and could potentially lead to bone puncture or other injuries.
Choice C Reason:
A depth of 3.0 mm significantly increases the risk of bone puncture, especially in infants with less subcutaneous fat or in those who are preterm. This depth could easily breach the protective layer of skin and subcutaneous tissue, leading to a higher risk of osteomyelitis, an infection of the bone, which can be a serious complication in infants.
Choice D Reason:
A depth of 3.5 mm is considered too deep for a heel stick procedure and is likely to cause injury to the infant. This depth would almost certainly penetrate the bone in most infants, leading to severe pain, potential for infection, and other complications. It is well beyond the safe range recommended by CLSI and should be avoided.
Which of the following accommodations should a phlebotomist make to increase a patient's comfort for venipuncture?
A. Turn the patient's hand palm down.
Turning the patient's hand palm down is not typically recommended as it can make the veins less accessible and may cause discomfort to the patient. The veins on the back of the hand are more superficial and can be more easily accessed when the hand is palm up.
B. Place the patient in a supine position.
Placing the patient in a supine position is not necessary for all venipuncture procedures and is usually reserved for patients who have a history of fainting or for those who are already lying down due to their medical condition. It is not a position that specifically increases comfort during the procedure.
C. Bend the patient's arm at the elbow.
Bending the patient's arm at the elbow can actually hinder the blood draw process as it may cause the veins to be less prominent and can lead to discomfort or movement during the venipuncture, potentially causing injury or an unsuccessful draw.
D. Position the patient's hand at waist level.
Positioning the patient's hand at waist level is the correct choice as it allows the arm to be in a natural, relaxed position, which can help the veins to be more prominent and accessible. It also helps in reducing the patient's anxiety as the arm is not in an awkward or strained position.
Full Explanation
Choice A reason:
Turning the patient's hand palm down is not typically recommended as it can make the veins less accessible and may cause discomfort to the patient. The veins on the back of the hand are more superficial and can be more easily accessed when the hand is palm up.
Choice B reason:
Placing the patient in a supine position is not necessary for all venipuncture procedures and is usually reserved for patients who have a history of fainting or for those who are already lying down due to their medical condition. It is not a position that specifically increases comfort during the procedure.
Choice C reason:
Bending the patient's arm at the elbow can actually hinder the blood draw process as it may cause the veins to be less prominent and can lead to discomfort or movement during the venipuncture, potentially causing injury or an unsuccessful draw.
Choice D reason:
Positioning the patient's hand at waist level is the correct choice as it allows the arm to be in a natural, relaxed position, which can help the veins to be more prominent and accessible. It also helps in reducing the patient's anxiety as the arm is not in an awkward or strained position.