Phlebotomy Final Exam Practice Part 1, 24 Questions

EDTA, which stands for ethylenediaminetetraacetic acid, is commonly used as an anticoagulant in lavender top tubes. It works by binding calcium ions, preventing blood from clotting. This allows for accurate testing of various blood parameters, such as complete blood count (CBC) and blood cell morphology. EDTA is a chelating agent that helps preserve the integrity of blood samples for analysis in the laboratory.

A tube with a green stopper usually contains heparin. Heparin is an anticoagulant medication that prevents blood from clotting. The green stopper indicates that the tube contains heparin, which is used to prevent blood clotting during laboratory tests or medical procedures.

PKU stands for Phenylketonuria, which is a genetic disorder characterized by the inability to metabolize phenylalanine, an amino acid found in many foods. This condition is caused by a deficiency of the enzyme phenylalanine hydroxylase, which is responsible for breaking down phenylalanine. As a result, phenylalanine builds up in the body and can cause intellectual disabilities, developmental delays, and other health problems if not managed through a restricted diet low in phenylalanine. Therefore, PKU is the correct answer that corresponds to the hereditary inability to metabolize phenylalanine.

The term "calcaneus" refers to the heel bone. It is the largest bone in the foot and forms the foundation of the heel. The calcaneus plays a crucial role in supporting body weight and providing stability during walking and running.

Skin puncture blood most closely resembles arterial blood because both types of blood come directly from the circulatory system. Arterial blood is oxygenated and carries nutrients to the body's tissues, while skin puncture blood is a mixture of capillary and venous blood. Since skin puncture blood is obtained by pricking the capillaries close to the skin's surface, it has a higher oxygen content compared to venous blood. Therefore, it closely resembles arterial blood in terms of oxygenation and nutrient content.

The correct answer is to look at the patient's ID band and ask the patient to state his name. This is the most reliable way to identify the patient as it involves verifying the information on the ID band and confirming it with the patient's own statement. Asking the patient directly if they are John Doe may not be as reliable as it relies solely on the patient's response, which could be inaccurate or misleading. Checking the ID band and stating that the patient is John Doe without confirming with the patient directly may also lead to errors if the ID band is incorrect or if there has been a mix-up.

The lateral plantar surface is the safest area for infant heel puncture because it has a thick layer of fat and is less likely to cause injury or damage to the underlying structures such as nerves or blood vessels. This area also has a good blood supply, making it easier to collect an adequate sample for testing.

An antiglycolytic agent is a substance that inhibits the breakdown of glucose in a sample. By preserving glucose, the sample can be accurately tested for various purposes, such as detecting diseases or monitoring glucose levels. Therefore, the statement that the purpose of an antiglycolytic agent is to preserve glucose is true.

When performing a skin puncture, it is important to control the depth of lancet insertion to avoid bone injury. If the lancet goes too deep, it can reach the underlying bone, causing damage and potential complications. By controlling the depth, healthcare professionals can ensure that the lancet only reaches the desired layer of skin and avoids any harm to the bone. This helps maintain the safety and integrity of the procedure, preventing unnecessary injuries to the patient.

Warming the site before skin puncture increases blood flow up to 7 times. This is beneficial because increased blood flow helps in making the veins more visible, making it easier to locate and puncture them. It also helps in preventing hemolysis of the sample, which is the breakdown of red blood cells. Additionally, increased blood flow can also provide comfort to the patient during the procedure.

The Clinical and Laboratory Standards Institute (CLSI) recommends a maximum depth of 2.0 mm for heel puncture. This depth is considered safe and sufficient for collecting an adequate blood sample from the heel of a patient. Going deeper than this recommended depth may increase the risk of injury or complications during the procedure. Therefore, healthcare professionals should adhere to this guideline to ensure the safety and well-being of the patient.

Coagulation tests are collected in a tube with a light blue stopper. This is because the light blue stopper indicates the presence of sodium citrate, which is an anticoagulant used to prevent blood from clotting. Coagulation tests measure the blood's ability to form clots, so it is important to use an anticoagulant to preserve the integrity of the sample. The use of a light blue stopper ensures that the correct tube is used for coagulation tests and helps to maintain the accuracy of the results.

Heparin prevents blood from clotting by inhibiting thrombin. Thrombin is a key enzyme in the blood clotting cascade that converts fibrinogen into fibrin, which forms the meshwork of a blood clot. By inhibiting thrombin, heparin prevents the formation of fibrin and therefore inhibits blood clotting. This is why heparin is commonly used as an anticoagulant medication to prevent and treat blood clots.

Antiseptics are substances used for skin cleaning that inhibit the growth of bacteria. They are commonly used to prevent infection in wounds or to sanitize the skin before medical procedures. Antiseptics work by killing or inhibiting the growth of bacteria, fungi, and other microorganisms on the skin's surface. They are different from disinfectants, which are used on non-living surfaces, and antibiotics, which are used to treat bacterial infections internally. Antiseptics are an essential tool in maintaining cleanliness and preventing the spread of harmful bacteria on the skin.

Vigorously pumping the patient's fist should not be used to enhance the vein selection process because it can cause the veins to collapse or become damaged, making it more difficult to find a suitable vein for venipuncture. This technique is not recommended as it can lead to inaccurate results and potential complications for the patient.

Skin puncture blood reference values for glucose are higher compared to other parameters such as calcium, phosphorous, and total protein. This is because glucose is an essential source of energy for the body and its levels need to be maintained within a certain range for proper bodily functions. Skin puncture blood sampling is a less invasive method compared to venous blood sampling, and it is commonly used for glucose testing in infants and young children. Therefore, the reference values for glucose in skin puncture blood samples are higher to account for the normal physiological variations in this population.

A skin puncture should be done instead of a venipuncture in all of the given situations except when a light blue stopper tube is needed. A skin puncture is typically preferred for children younger than 1 year of age because their veins are small and delicate, making it easier and less traumatic to obtain a blood sample. It is also preferred for patients with difficult veins, as a skin puncture can be less challenging and more successful in such cases. Additionally, when a small volume of blood is needed, a skin puncture is preferred as it provides a sufficient sample size without causing excessive blood loss. However, when a light blue stopper tube is needed, it indicates the need for a specific type of blood collection tube for coagulation testing, which is better obtained through venipuncture rather than a skin puncture.

Sodium hypochlorite is not an antiseptic because it is primarily used as a disinfectant and bleach rather than for preventing infection on living tissues. Antiseptics are substances that are applied to living tissues to kill or inhibit the growth of microorganisms, while disinfectants are used on inanimate objects or surfaces to kill or reduce the number of microorganisms present. Benzalkonium chloride, isopropanol, and providone-iodine are all examples of antiseptics commonly used for wound care and disinfection purposes.

The size and condition of the vein are the most important factors in choosing the gauge needle for venipuncture. The size of the vein determines the appropriate gauge needle to ensure successful insertion and withdrawal of blood. A larger vein may require a larger gauge needle to accommodate the flow, while a smaller vein may require a smaller gauge needle to minimize discomfort and potential damage. The condition of the vein, such as its visibility, fragility, or presence of any abnormalities, also influences the choice of needle gauge to minimize complications and ensure safe and effective blood collection.

Glass particles present in serum separator tubes are known to accelerate coagulation. This is because the rough surface of the glass particles provides a suitable surface for the activation of the coagulation cascade, leading to the formation of a clot more quickly. The presence of glass particles in the tube enhances the interaction between clotting factors and platelets, promoting the clotting process. This is beneficial in clinical settings where rapid coagulation is desired, such as in blood tests or when collecting samples for analysis.

Sodium fluoride is the best tube for collecting an ethanol specimen because it acts as a preservative and inhibits the growth of microorganisms in the specimen. It also prevents the breakdown of ethanol by enzymes, ensuring accurate and reliable results. EDTA, siliceous earth, and sodium citrate are not suitable for collecting ethanol specimens as they do not have the same preservative and inhibitory properties as sodium fluoride.

A laboratory report form should indicate the fact that a specimen has been collected by skin puncture because test results may vary depending on the method of collection. Skin puncture is a different method of collecting a specimen compared to other methods such as venipuncture. Different collection methods can potentially affect the composition of the specimen, leading to variations in test results. By indicating that a specimen has been collected by skin puncture, healthcare professionals and laboratory technicians can take this into consideration while interpreting the test results and making accurate diagnoses.

The correct answer is SPS/ACD because these additives are commonly used in yellow-topped tubes for microbiology testing. SPS (Sodium Polyanethol Sulfonate) is an anticoagulant that prevents blood clotting, while ACD (acid citrate dextrose) is a preservative that helps maintain the integrity of the sample during transportation and storage. These additives are specifically chosen for microbiology testing to ensure accurate and reliable results.

EDTA (Ethylenediaminetetraacetic acid) is an anticoagulant commonly used in blood collection to prevent clotting. When collecting blood by skin puncture, EDTA specimens are obtained before other specimens to minimize the effects of platelet clumping. Platelet clumping can occur when blood is exposed to air or when there is delay in processing the sample. By collecting EDTA specimens first, platelet clumping is minimized, ensuring accurate and reliable test results.