NCCT Practice Test - Lab Review Part One

An alcohol prep is used to cleanse the venipuncture site before drawing blood. It is important to clean the area to prevent the introduction of bacteria or other contaminants into the bloodstream. Alcohol is commonly used for this purpose as it has antimicrobial properties and can effectively disinfect the skin. Using a damp solution, a paper towel, or the back of your hand would not provide the same level of cleanliness and disinfection as an alcohol prep.

When performing a venipuncture, making a fist can help to make the veins more prominent. This is because when the patient makes a fist, it causes the muscles in the forearm to contract, which in turn increases the blood flow to the area. This increased blood flow makes the veins more visible and easier to locate for the healthcare professional performing the venipuncture.

A centrifuge is a laboratory instrument that spins samples at high speeds to separate components based on their density. In the case of blood, a centrifuge is used to separate the cellular components (red and white blood cells) from the liquid portion (plasma or serum). This separation allows for further analysis of the blood components and is commonly used in medical and research settings.

The lid to the centrifuge should be kept closed when in use to ensure the safety and effectiveness of the process. Keeping the lid closed prevents any potential accidents or spills that may occur if the lid is open or ajar. Additionally, a closed lid helps maintain the necessary pressure and temperature conditions inside the centrifuge for accurate and reliable results. Therefore, it is important to keep the lid closed during operation.

A lancet is a small, sterile, needle-like piece of metal used to make small punctures in the dermis. It is commonly used in medical procedures such as blood glucose testing or to obtain a small sample of blood for diagnostic purposes.

In the evacuated blood collection system, the evacuated glass tubes come in different sizes, and the stoppers are color coded to denote the type of additive or lack of one. This means that each color represents a specific additive or indicates the absence of any additive. The color coding system helps ensure that the correct tube is used for each specific test or procedure, reducing the risk of errors and ensuring accurate results.

When searching for a vein, it is important to palpate, which means to use your index finger to feel or examine the area. This technique allows healthcare professionals to locate the vein by feeling its size, texture, and direction, making it easier to successfully inject or draw blood. Sticking or scratching would not be appropriate actions in this context, and injecting would come after the vein has been located through palpation.

The higher the gauge number, the smaller the needle. This is because the gauge number refers to the thickness of the needle. So, a higher gauge number indicates a thinner needle, making it smaller in size.

When cleansing the venipuncture site, it is good practice to cleanse the site from the inside out and allow it to air dry. This helps to remove any microorganisms present on the skin and reduces the risk of introducing them into the bloodstream during the venipuncture procedure. Allowing the site to air dry is important as it prevents the introduction of contaminants from towels or other materials. It is not recommended to wipe the site back and forth quickly with an alcohol prep as it may not effectively cleanse the site. Blowing on the alcohol to dry it is also not recommended as it can introduce saliva and bacteria onto the site. Having the patient wave the arm in the air to dry it faster is not necessary and may cause discomfort to the patient.

The blood lancet is used for the collection of blood specimens by skin puncture. This involves making a small incision or puncture on the skin to obtain a blood sample. This method is commonly used for diagnostic testing, such as blood glucose monitoring or blood typing, as it is less invasive and requires a smaller amount of blood compared to other methods like injections or suction.

Drawing blood usually requires the use of a tourniquet to make the veins more visible and easier to access. However, leaving the tourniquet tied for too long can cause complications such as venous stasis and ischemia. This can lead to blood clots, tissue damage, and other potential risks. Therefore, it is recommended to tie the tourniquet for a maximum of 1 minute to minimize these risks and ensure the safety and well-being of the patient.

To cleanse the typical venipuncture site, it is recommended to work in a circle to the periphery. This technique ensures that the entire area is properly cleaned and disinfected before the venipuncture procedure. By starting at the intended site of the draw and working in a circular motion towards the outer edges, any potential contaminants or bacteria are effectively removed from the skin surface. This method helps to minimize the risk of infection and ensures a clean and sterile environment for the venipuncture procedure.

Positively identifying the patient is the most important step in the performance of a venipuncture because it ensures that the correct patient is receiving the procedure. This step helps to prevent any potential errors or complications that may arise from performing the procedure on the wrong individual. It also helps to maintain patient safety and confidentiality by ensuring that the correct patient's medical records and test results are accurately recorded.

When preparing to feel for a vein, it is recommended to wrap the tourniquet around the arm approximately three to four inches above the area. This distance allows for proper compression of the veins, making them easier to locate and access for medical procedures such as drawing blood or administering medication. Wrapping the tourniquet too tightly or too loosely can hinder the process and potentially cause discomfort or complications for the patient.

If a patient has a syncopal episode during a venipuncture, the best course of action would be to remove the needle and tourniquet and lower the patient's head and arms. This is because lowering the head and arms helps to improve blood flow to the brain, preventing further complications. Removing the needle and tourniquet is necessary to avoid any potential injury or complications that may arise from continuing the procedure. CPR and activating 911 would not be necessary in this situation unless the patient's condition deteriorates further. Restraining the patient is not recommended as it may cause more harm.

When performing a capillary stick, it is important to wipe away the first drop of blood. This is because the first drop may contain tissue fluid or contaminants from the puncture site, which could affect the accuracy of the blood sample. By wiping away the first drop, we ensure that we are collecting a clean and uncontaminated blood sample for testing or analysis.

The standard point of the lancet to be used when collecting blood from a newborn heel is 2.4 MM in length. This length is specifically chosen to ensure a small and precise incision is made in the newborn's heel, allowing for an adequate amount of blood to be collected for testing purposes without causing excessive pain or damage to the baby's delicate skin.

When performing a venipuncture, the tourniquet should be wrapped around the arm about three to four inches from where you are going to feel for a vein. This is because wrapping the tourniquet tightly around the arm helps to engorge the veins and make them more visible and palpable. By feeling for a vein in this area, the healthcare professional can locate a suitable vein for the venipuncture procedure.

Capillary puncture is a technique used to collect blood samples for various laboratory tests. In a healthy adult, the most suitable site for performing a capillary puncture is the fingers. This is because the fingers have an abundant supply of capillaries close to the surface of the skin, making it easier to obtain an adequate blood sample. Additionally, the fingers are easily accessible and provide a convenient site for the procedure. Other sites such as the great toe, earlobes, and forearms may be used in specific situations, but the fingers are generally preferred.

When using the centrifuge, it is important to ensure that equal weights are placed opposite each other. This is because the centrifuge spins at high speeds, creating a centrifugal force that pushes objects away from the center. Placing equal weights opposite each other helps to balance the centrifuge and prevent it from becoming unbalanced during the spinning process. This ensures accurate and reliable results.

Arterioles are the smallest type of blood vessels that branch out from arteries and carry oxygenated blood to the capillaries. They play a crucial role in regulating blood flow and blood pressure. Tendons, bones, and veins are not related to the size or function of arterioles, making arteries the correct answer.

During a venipuncture, a holder is needed to secure the needle during insertion into the tube stopper. This is because the holder provides stability and control, ensuring that the needle is properly inserted and does not move or slip during the procedure. It helps to maintain the correct angle and depth of insertion, reducing the risk of complications such as hematoma or infiltration. Additionally, a holder allows the healthcare professional to have a firm grip on the needle, enhancing their ability to perform the venipuncture accurately and efficiently.

The question is asking which tube would be drawn first. The answer is "red" because it is the first option listed.

When collecting blood by skin puncture on an infant, it is recommended to use a lancet. A lancet is a small, sharp instrument specifically designed for puncturing the skin to obtain a blood sample. It is commonly used in pediatric settings because it minimizes pain and trauma to the infant's delicate skin. The other options, such as the 25 ga needle, 23 ga needle, and scalpel, are not typically used for skin punctures in infants due to their larger size and increased risk of causing discomfort or injury.

The most commonly used needle gauges for venipuncture are 21-22. These gauges are preferred because they are large enough to allow for the easy withdrawal of blood, but not so large that they cause excessive pain or damage to the veins. The 21-22 gauge needles strike a balance between being effective for drawing blood and being comfortable for the patient.

A glucose tolerance test requires the patient to be fasting and then blood is taken every hour for a predetermined time. This test is used to measure how well the body can process glucose and diagnose conditions such as diabetes.

When anticoagulated blood is centrifuged, the different components of the blood separate based on their density. The heaviest component, red blood cells, settle at the bottom of the tube due to their high density. The lighter component, plasma, rises to the top of the tube as it has a lower density compared to the red blood cells. Therefore, when anticoagulated blood is centrifuged, plasma goes to the top of the tube.

The color coding for a stopper of a tube with no additives is red for the collection of serum. This color coding system is used in medical laboratories to indicate the type of tube and the specific tests to be performed on the collected sample. The red stopper is commonly used for serum collection, as it helps to differentiate it from other types of tubes used for different purposes, such as anticoagulant tubes or tubes with additives.

The cephalic, medial cubital, and basilic veins are primarily used for venipuncture. This means that these veins are the main or most commonly used veins for drawing blood or administering intravenous medications. Other veins may be used in certain situations, but these three veins are the preferred choices for venipuncture procedures.

If no blood flows into the tube during a venipuncture, it could be due to various reasons such as a shallow needle insertion, a blocked or kinked needle, or a collapsed vein. To correct this situation, any of the given options could be correct depending on the specific circumstances. Gently inserting the needle a little deeper may help reach the vein and allow blood flow. Gently pulling the needle out just a little may help if the needle was inserted too deep and caused the needle to exit the vein. Removing the needle and tourniquet and preparing another site may be necessary if the vein cannot be accessed or if the issue persists.

When doing a venipuncture, the syringe or tube should be positioned below the venipuncture site to prevent backflow. This is because gravity helps to ensure that blood flows smoothly into the syringe or tube without any obstruction or reflux. Placing the syringe or tube above the venipuncture site could cause blood to flow back into the vein, potentially leading to contamination or clotting. Therefore, positioning it below the site is the correct technique to maintain proper blood flow during the procedure.

PT (Prothrombin Time) and PTT (Partial Thromboplastin Time) are lab tests that monitor anticoagulation therapy. PT measures the time it takes for blood to clot and is used to monitor patients taking the anticoagulant drug warfarin. PTT measures the time it takes for blood to clot in response to certain medications and is used to monitor patients taking heparin or other anticoagulant medications. These tests help healthcare providers determine if the dosage of anticoagulant medication is appropriate and if the patient is at risk of bleeding or clotting.

The correct answer is lavender top - ethylenediaminetetraacetic acid additive. Ethylenediaminetetraacetic acid (EDTA) is commonly used as an anticoagulant in blood collection tubes for a complete blood count (CBC). It prevents blood from clotting by binding to calcium ions, allowing the blood sample to be preserved for analysis. The lavender top tube is specifically designed for hematology testing, which includes CBC.

In order to properly prepare for a glucose tolerance test, the patient should refrain from eating, smoking, drinking coffee, or consuming alcohol for a period of ten hours before or during the test. This is necessary to ensure accurate results and avoid any interference with the body's glucose levels.

When anticoagulated blood is centrifuged, the red blood cells settle at the bottom of the tube due to their higher density compared to other components. This separation occurs because the centrifugal force causes the denser particles to move towards the outer edge of the tube, while the less dense components like plasma and water remain towards the top. Therefore, the correct answer is red blood cells.

Erythrocyte sedimentation rates are increased in infections and inflammatory diseases. This is because during these conditions, there is an increase in certain proteins in the blood that cause red blood cells to stick together and settle more quickly. This leads to an elevated sedimentation rate, which is a non-specific marker of inflammation and can help in diagnosing and monitoring these conditions.

The correct answer is lavender-top. A hematocrit test measures the percentage of red blood cells in the total blood volume. Lavender-top tubes are typically used for collecting blood samples for complete blood count (CBC) tests, which include hematocrit measurements. These tubes contain an anticoagulant called EDTA, which prevents the blood from clotting and allows for accurate measurement of the red blood cell percentage. Red-top tubes are used for tests that require serum, while blue-top and yellow-top tubes are used for other types of tests.

The correct answer is 2 because hematocrit tubes are used to measure the percentage of red blood cells in a patient's blood. Typically, two tubes are collected in order to perform duplicate measurements and ensure accurate results. Collecting only one tube may lead to inaccurate readings or potential errors. Therefore, it is necessary to collect two hematocrit tubes from the patient.

Veins pulsate is the false statement. Veins do not pulsate like arteries do. Arteries have a strong pulse due to the pumping of blood from the heart, while veins carry blood back to the heart and do not have a strong pulsation.

Rubber sleeves on an evacuated tube system make it possible for multiple use. The rubber sleeves act as a barrier between the blood and the tube, preventing contamination and allowing the tube to be reused for different patients. This reduces the need for constantly replacing the tubes, making it more cost-effective and efficient in healthcare settings.

To perform a hemoglobin test, the blood sample needed would be one that has EDTA added to it. EDTA is an anticoagulant that prevents the blood from clotting, allowing for accurate measurement of hemoglobin levels. Serum only or white blood cells would not be appropriate for this test, as they do not provide the necessary components for hemoglobin measurement. Therefore, the correct answer is EDTA added.

The correct answer is "chain of custody." In drug testing, the chain of custody refers to the process of documenting and maintaining the control and integrity of the evidence from the moment it is collected until it is presented in court. It involves ensuring that the evidence is properly handled, stored, and transferred without any tampering or contamination. This is crucial to maintain the reliability and admissibility of the evidence in legal proceedings.

When performing a PKU (phenylketonuria) test, a capillary blood sample is needed. This is because capillary blood can be easily obtained through a fingerstick, making it a less invasive method compared to venipuncture. Additionally, capillary blood is often preferred for PKU testing as it provides a more accurate representation of blood levels in newborns, who are typically screened for this condition. Therefore, capillary blood is the appropriate type of blood sample for performing a PKU.

The red-top tube is the correct choice for collecting electrolytes using an evacuated tube. This is because the red-top tube contains no additives or anticoagulants, which makes it suitable for collecting serum samples. Electrolytes are typically measured in serum, and using a red-top tube ensures that the sample is not contaminated with any additives that could affect the test results.

When collecting blood for cholesterol tests, it is recommended to use a red top evacuated tube. This is because red top tubes typically contain no additives, allowing for the collection of a serum sample. Cholesterol levels are commonly measured in the serum, and using a red top tube ensures that the sample collected is suitable for accurate cholesterol testing.

In order to ensure accuracy and patient safety, it is essential to have a quality control plan in place at healthcare facilities. This plan includes various measures to maintain the quality and accuracy of processes, such as making sure that tubes are correctly labeled with the patients' complete name and identification number. This helps to prevent any mix-ups or errors in patient identification, ultimately contributing to the overall quality and safety of patient care.

The tube to collect whole blood with an additive in it has a lavender stopper. Different colored stoppers are used to indicate different types of additives or anticoagulants present in the tube. Lavender stoppers are commonly used for tubes containing the anticoagulant EDTA, which is used to prevent blood from clotting. This type of tube is typically used for complete blood count (CBC) tests, as EDTA preserves blood cell morphology and allows for accurate analysis of different blood cell types.

Performing a hematocrit as part of a complete blood count (CBC) determines the ratio of volume packed red blood cells to that of whole blood. Hematocrit is a measure of the percentage of red blood cells in the blood, indicating the blood's ability to carry oxygen. This test helps in diagnosing conditions such as anemia and polycythemia. It is an important component of a CBC as it provides valuable information about the overall health and functioning of the blood.

Sodium citrate is an anticoagulant of choice for coagulation studies because it protects certain pro coagulants.

EDTA is used as an anticoagulant additive because it removes calcium, which is necessary for the clotting process. By forming insoluble or un-ionized calcium salts, EDTA prevents platelet clumping and the formation of artifacts. This makes it beneficial for the preparation of blood films, as it helps to maintain the integrity of the blood sample and prevent unwanted clotting. Therefore, the correct answer is blood films.