Capillary and Dermal Puncture Flashcards
8 cards from real Phlebotomy Test practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 8 Capillary and Dermal Puncture flashcards as text
What is the primary reason that EDTA tubes are collected FIRST in the capillary order of draw?
Answer: To ensure the hematology specimen is collected before platelet clumping and activation occur
In capillary collection, EDTA tubes are first because the trauma of skin puncture activates platelets immediately; early collection captures the most representative sample before significant platelet clumping occurs.
A phlebotomist must collect a capillary sample for neonatal glucose monitoring. The nurse requests a stat result. Which Microtainer tube should be used?
Answer: Gray (sodium fluoride/potassium oxalate)
Gray-top (sodium fluoride/potassium oxalate) Microtainer tubes are used for glucose because sodium fluoride inhibits glycolysis, preserving glucose concentration in the sample.
When performing a heelstick on a preterm neonate (born at 28 weeks gestation), the maximum lancet depth should be:
Answer: 0.65 mm (the shallowest commercially available device)
Preterm neonates have extremely thin skin and very little subcutaneous tissue; the shallowest commercially available neonatal lancet (0.65–0.85 mm) should be used to avoid bone puncture.
The term 'arterialized capillary blood' refers to blood obtained after:
Answer: Warming the site to increase local arterial blood flow
Warming the site for 3–5 minutes vasodilates local arterioles and increases arterial contribution to capillary blood, making its composition closer to arterial blood.
Which of the following is the CORRECT technique for applying blood to a newborn screening filter paper card?
Answer: Touch the blood drop to the center of the circle and allow it to soak through in a single application
The correct technique is to touch the edge or center of the filter paper circle to the blood drop and let it saturate the circle in one application, without layering or pressing against the wound.
A phlebotomist needs to collect a capillary specimen from a patient with severe bilateral hand edema. The BEST alternative site would be:
Answer: The earlobe
The earlobe is an acceptable alternative capillary puncture site when finger sites are compromised by edema, burns, or inadequate circulation.
How long should isopropyl alcohol be allowed to dry before performing a capillary puncture?
Answer: Until it is completely dry (30–60 seconds)
Isopropyl alcohol must dry completely (30–60 seconds or until visually dry) before puncture; residual alcohol causes burning pain, hemolyzes the specimen, and can contaminate the sample.
In capillary puncture, which of the following causes the LEAST amount of pain and tissue damage while still providing adequate blood?
Answer: An automated spring-loaded safety lancet of appropriate gauge and depth
Automated spring-loaded safety lancets provide a controlled, consistent puncture depth and width, minimize tissue trauma, retract automatically for safety, and produce less pain than manual devices.