Dermal Puncture Medical Quiz
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Questions and Answers

What is the primary reason for using special collection kits in newborn screening?

  • To ensure the collection from other blood sources.
  • To increase the volume of blood collected.
  • To prevent contamination of specimens. (correct)
  • To facilitate temperature control during transport.

    • Which condition is characterized by the lack or absence of thyroid hormone in newborn screening?

  • Phenylketonuria (PKU)
  • Congenital Hypothyroidism (CH) (correct)
  • Galactosemia (GAL)
  • Congenital Adrenal Hyperplasia (CAH)

    • What could lead to contamination of a blood specimen during collection?

  • Collecting blood after 72 hours.
  • Performing heel puncture correctly.
  • Using sterile gloves.
  • Touching the area inside the circles. (correct)

    • What is a significant effect of Congenital Adrenal Hyperplasia (CAH) on infants?

    <p>Severe salt loss and dehydration.</p> Signup and view all the answers

    Which disorder from the newborn screening panel affects the metabolism of phenylalanine?

    <p>Phenylketonuria (PKU)</p> Signup and view all the answers

    What should be avoided to prevent contamination of a specimen during a dermal puncture?

    <p>Using a swollen or previously punctured site</p> Signup and view all the answers

    What is the recommended method to warm the puncture site?

    <p>Moistening a towel with warm water at 42°C for 3 to 5 minutes</p> Signup and view all the answers

    What action should be taken after cleaning the site with alcohol?

    <p>Allow the alcohol to dry and remove excess with gauze</p> Signup and view all the answers

    In which situation is warming the puncture site particularly necessary?

    <p>For heel punctures and cold or cyanotic fingers</p> Signup and view all the answers

    Why is povidone-iodine not used for routine dermal punctures?

    <p>It can elevate certain test results</p> Signup and view all the answers

    What negative effect can result from not allowing isopropyl alcohol to dry before performing a puncture?

    <p>Hemolysis of red blood cells</p> Signup and view all the answers

    How should the heel be positioned prior to performing a heel puncture?

    <p>Support the heel firmly without squeezing it</p> Signup and view all the answers

    What is a potential risk of warming the puncture site for longer than 10 minutes?

    <p>Alteration in test results</p> Signup and view all the answers

    What is the recommended position for capillary tubes and micropipettes while filling?

    <p>Horizontally</p> Signup and view all the answers

    What can interfere with blood gas determinations?

    <p>Air bubbles</p> Signup and view all the answers

    During the collection process of microcollection tubes, how should the tubes be held?

    <p>Slanted to ensure smooth blood flow</p> Signup and view all the answers

    What may occur if blood collection takes more than 2 minutes?

    <p>Microclots may form</p> Signup and view all the answers

    What should be done with microcollection tubes filled with anticoagulants after collection?

    <p>Invert them five to ten times</p> Signup and view all the answers

    What could happen if a microcollection tube is underfilled?

    <p>It can cause morphological changes in cells</p> Signup and view all the answers

    Why is the order of draw important when collecting multiple specimens from a dermal puncture?

    <p>Platelets tend to accumulate at the wound site</p> Signup and view all the answers

    What technique may be necessary to ensure the blood flows to the bottom of the microcollection tube?

    <p>Gently tapping the bottom of the tube</p> Signup and view all the answers

    What is the primary reason dermal puncture is preferred for infants and children under 2 years old?

    <p>Superficial veins are hard to locate and deep veins pose risks.</p> Signup and view all the answers

    Which situation might prevent the use of dermal puncture for blood collection?

    <p>The patient is dehydrated or has poor peripheral circulation.</p> Signup and view all the answers

    What is a common risk associated with dermal puncture that can affect the quality of the specimen?

    <p>Specimen contamination.</p> Signup and view all the answers

    What type of blood is obtained through dermal puncture?

    <p>A mixture of capillary, arterial, and venous blood.</p> Signup and view all the answers

    What should be done with the puncture device immediately after use?

    <p>Discard it in an approved sharps container</p> Signup and view all the answers

    Which of the following is NOT a recommended practice for dermal puncture?

    <p>Applying excessive pressure during blood collection.</p> Signup and view all the answers

    For which type of test is dermal puncture particularly useful?

    <p>Newborn screening tests.</p> Signup and view all the answers

    Why is it important to wipe away the first drop of blood before collection?

    <p>It prevents contamination with alcohol and tissue fluid</p> Signup and view all the answers

    What technique should be avoided when trying to collect blood?

    <p>Milking the surrounding tissue</p> Signup and view all the answers

    What is a key factor that can lead to hemolysis during a dermal puncture?

    <p>Milking the puncture site.</p> Signup and view all the answers

    How can you improve blood flow during collection?

    <p>Apply pressure about 1/2 inch away from the puncture site</p> Signup and view all the answers

    Which patient condition makes it difficult to perform dermal puncture effectively?

    <p>Being obese or apprehensive.</p> Signup and view all the answers

    What should be done with the capillary tube while it is filling?

    <p>Hold it horizontally</p> Signup and view all the answers

    What can interfere with blood gas determinations?

    <p>Air bubbles in the specimen</p> Signup and view all the answers

    What method should be used to seal the microhematocrit tube after filling?

    <p>Use a plastic cap</p> Signup and view all the answers

    What should be avoided to prevent hemolysis of the specimen?

    <p>Tightly squeezing the puncture site</p> Signup and view all the answers

    Study Notes

    Dermal Puncture

    • Also known as skin puncture or capillary puncture.
    • Preferred method for blood collection in infants and children under 2 years old due to difficulty locating superficial veins, risks associated with deep vein puncture, prevention of iatrogenic anemia, specific test requirements (e.g., newborn screening), and potential injury from restraining.
    • May also be necessary for adults with burns/scars, chemotherapy patients, obese individuals, apprehensive patients, those with thrombotic issues, geriatric patients with fragile veins, and those using home glucose monitoring or point-of-care testing (POCT).
    • Not suitable for severely dehydrated patients, those with poor peripheral circulation, or swollen fingers. Certain tests (coagulation studies, ESR, blood cultures) require larger blood volumes than usually obtained via dermal puncture.

    Importance of Correct Collection

    • Specimen contamination must be avoided.
    • Microclot formation is a concern.
    • Hemolysis is more frequent.

    Hemolysis Causes

    • Excessive squeezing of the puncture site.
    • Increased RBC count and fragility in newborns.
    • Residual alcohol at the site.
    • Vigorous mixing of microcollection tubes.

    Capillary Blood Composition

    • A mixture of capillary, arterial, and venous blood with small amounts of interstitial and intracellular fluid.

    Dermal Puncture Equipment

    • Automatic retractable safety skin puncture devices.
    • Microcollection containers.
    • 70% isopropyl alcohol pads, gauze pads, bandages.

    Site Selection

    • Avoid thumbs (calluses), index fingers (increased nerve endings), and fifth fingers (decreased tissue).
    • Do not use swollen or previously punctured sites; these will contaminate the specimen due to increased tissue fluid.
    • Earlobes are not recommended.

    Warming the Site (Optional)

    • Improves blood flow by dilating blood vessels and increasing arterial flow.
    • Primarily for patients with cold/cyanotic fingers, multiple specimen heel punctures, and capillary blood gas (CBG) collection.
    • Warm with a 42°C moist towel or commercial heel warmer for 3–5 minutes; do not exceed 10 minutes.

    Cleaning the Site

    • Use 70% isopropyl alcohol; allow to dry completely before collecting blood.
    • Do not use povidone-iodine in routine extraction (except for blood cultures and blood donation); it can contaminate specimens and elevate bilirubin, phosphorus, uric acid, and potassium levels.

    Performing the Puncture

    • Ensure proper support and firm hold of the heel or finger without squeezing the puncture area.
    • Apply gentle pressure before puncturing to increase blood flow.
    • Proper heel puncture technique includes holding the heel with thumb and index finger around the arch, and surrounding fingers wrapping around the top of the foot.
    • Dispose of puncture devices immediately after use in designated sharps containers. A new device is needed for additional punctures.

    Specimen Collection

    • Wipe away the first drop of blood to prevent contamination from alcohol and tissue fluid.
    • Blood should flow freely; avoid "milking". Alternate pressure application yields better results.
    • Avoid applying pressure very close to the puncture site; applying pressure further away may be better.
    • Do not touch the puncture site with the lancet, as this leads to contamination and hemolysis.
    • Position fingers downward to use gravity to fill capillaries. Do not use a scooping motion.

    Capillary Tubes and Micropipettes

    • Lightly touch the collection tip to the blood drop to draw it into the tube.
    • Keep tubes horizontal during filling to prevent air bubbles (which interfere with blood gas determinations).
    • Seal with sealant clay or designated caps. Apply sealant using twisting motion to firmly plug tubes.

    Microcollection Tubes

    • Hold at a slant, placing the tip beneath the drop. First 3 drops form a channel for blood flow. Gentle tapping may be needed.
    • When full, add the color-coded top.
    • Invert tubes with anticoagulants 5–10 times or as manufacturer directs.
    • For slow blood flow, mix the tube during collection; collecting blood in more than 2 minutes may result in microclot formation.
    • Collect the correct amount of blood; overfilling can lead to clotting while underfilling can alter cell morphology.

    Order of Collection

    • Order is important due to platelet accumulation.
    • Use special kits with preprinted circles on filter paper; avoid touching the circles.
    • Prevent contamination with water, formula, alcohol, urine, lotions, or powder.

    Newborn Screening

    • Typically collected 24-72 hours after birth via heel puncture by a medical technician, nurse, or physician.
    • Use special kits; avoid contamination.

    Newborn Screening Panel Diseases

    • Congenital Hypothyroidism (CH): Lack of thyroid hormone.
    • Congenital Adrenal Hyperplasia (CAH): Severe salt loss, dehydration, high male sex hormone levels.
    • Galactosemia (GAL): Inability to process galactose.
    • Phenylketonuria (PKU): Inability to properly use phenylalanine.
    • Glucose-6-Phosphate Dehydrogenase Deficiency (G-6-PD def): Lack of G-6-PD enzyme. Most common.

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    Related Documents

    Dermal Puncture & Equipments PDF

    Description

    Test your knowledge on dermal puncture techniques and their significance in blood collection, particularly for infants and patients with special conditions. Learn about the advantages, contraindications, and best practices to ensure accurate specimen collection. This quiz provides essential information for healthcare professionals.

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