60 Questions
What is the primary reason for following the order of the draw for capillary blood collection?
To reduce the risk of blood clotting
Why is it important to collect blood gases first in capillary blood collection?
To obtain a accurate blood gas result
What type of additive is present in purple, lavender, pink, or pearl cap tubes?
EDTA
Why is it important to collect EDTA tubes as close to first as possible?
To prevent clotting of the blood
What type of additive is present in green cap tubes?
Heparin
What is the purpose of collecting serum specimens last in the order of the draw?
To allow the blood to clot
What is the primary purpose of following the CLSI order of the draw for capillary blood collection?
To ensure the accuracy of the blood test results
What happens to the blood as soon as the flow begins in a dermal puncture?
It begins to clot
What is the recommended depth of a lancet for a child weighing less than or equal to 1 kg?
0.65 mm
What is the primary reason for not using the back of the heel for a heel stick?
There is too little skin/tissue in that area
Why should you not squeeze the heel for a long time or use excessive pressure during a heel stick?
It can affect the accuracy of the test results
What should you do if the flow of blood stops during a heel stick?
Wipe away any surface clots with a gauze pad and stop squeezing the heel
What is the purpose of wiping away the first drop of blood during a heel stick?
To obtain a clean sample
Why should you not use a site that was recently used or has a hematoma or scratch for a heel stick?
It may cause further damage to the skin
What is the recommended time for applying the heel warmer before a heel stick?
3 to 5 minutes
What should you do after filling the collection tubes during a heel stick?
Label the tubes and apply pressure to the puncture site
Why should adhesive bandages not be used on infants after a dermal puncture?
Because they can remove the bandage and swallow it
What is the purpose of a heel warming device in a heel stick procedure?
To increase blood flow to the area
Why should the first drop of blood be wiped away during a dermal puncture?
To prevent hemolysis of the specimen
What should be done to the filled tubes after capping?
Gently invert to mix
Why is a heel stick used for infants younger than 12 months?
Because the infant's veins are too small for a standard venipuncture
What should be done to prevent bleeding after a dermal puncture?
Apply gentle pressure to the puncture site
What should be done to the puncture site after bleeding has stopped?
Apply an adhesive bandage (for adults and responsible children)
Why should the equipment be assembled before performing a heel stick?
To ensure all necessary equipment is available
When is a capillary blood collection preferred over a venipuncture in adults?
When the test is to be performed repeatedly
Where should a dermal puncture be performed on an infant up to 1 year old?
Heel
What is the first step in the dermal puncture procedure?
Introduce yourself
What should you avoid performing a finger stick on?
All of the above
What is the purpose of washing hands before the dermal puncture procedure?
To prevent infection
What should you check before performing a dermal puncture on an adult?
The warmth of the hand
Why should you avoid using the thumb for a dermal puncture?
It has a pulse
What should you do to position the patient before the dermal puncture procedure?
Have the patient sit or lie down
Why is a capillary blood collection preferred for infants younger than 1 year old?
Because it requires less blood and reduces the risk of iatrogenic anemia
What is an advantage of using capillary blood collection for patients who are underweight?
It reduces the risk of iatrogenic anemia
What is a characteristic of a dermal puncture blood specimen?
It contains a mixture of arterial, capillary, and venous blood
Why is it important to document the use of a dermal puncture on the medical requisition?
To alert the laboratory of the different composition of the blood
Which of the following is a common use for capillary blood collection?
For point-of-care (POC) blood tests, such as glucose and cholesterol
In which situations may a capillary collection be necessary?
When a patient does not have an accessible vein or is at risk of iatrogenic anemia
What is a reason why capillary blood collection may be preferred over venipuncture?
It reduces the risk of iatrogenic anemia
Why may a capillary collection be used for older adults?
Because they have compromised veins that are difficult to find
You should use a lancet that punctures the skin to a depth of 2 mm for a child weighing less than or equal to 1 kg.
False
After filling the collection tubes during a heel stick, you should release the pressure on the puncture site.
False
The best site for a heel stick is the back of the heel.
False
You should use a lancet with a depth of 1 mm for infants.
True
You should squeeze the heel for a long time to get a sufficient blood sample.
False
You should apply the heel warmer for 1 minute before a heel stick.
False
In capillary blood collection, the order of the draw is followed to prevent additive cross-contamination.
False
The blood gas collections are collected last in the capillary order of the draw.
False
EDTA tubes contain the additive heparin.
False
Serum specimens are collected before EDTA tubes in the capillary order of the draw.
False
The order of the draw is the same for both venipuncture and capillary blood collection.
False
The blood begins to clot immediately after the flow begins in a dermal puncture.
True
The lancet should puncture the skin to a depth of at least 3 mm for a heel stick.
False
Adults can use a heel stick for capillary blood collection.
False
Gloves should be removed before washing hands after the dermal puncture procedure.
False
A heel warming device is required for a heel stick procedure.
False
The first drop of blood should be collected and used for testing during a dermal puncture.
False
A capillary blood collection is preferred for patients who are overweight.
False
The order of draw for capillary blood collection is the same as for venipuncture.
False
Adhesive bandages should be used on all patients, regardless of age, after a dermal puncture.
False
Study Notes
Heel Stick Procedure for Infants
- Choose a lancet that punctures the skin to a depth of 0.65 mm if the infant's weight is equal to or less than 1 kg.
- Position the infant supine, if possible, and check with the nurse or provider for any restrictions on positioning.
- Apply a heel warmer for 3 to 5 minutes.
- Wash your hands and don gloves.
- Select a site on the lateral or medial sides of the heel, avoiding the back of the heel.
- Cleanse the site and place the lancet on the skin to make the puncture.
- Gently squeeze the heel to collect blood, but avoid excessive pressure or squeezing for too long.
Capillary Blood Collection
- Also known as dermal puncture or finger stick
- Used for tests requiring a small amount of blood, when a patient has no accessible vein, or when the test requires capillary blood
- Preferred method for infants younger than 1 year old due to small vein size and risk of iatrogenic anemia
Order of Draw for Capillary Collection
- Blood gas collections: collect first to ensure accurate representation of patient's blood
- EDTA tubes (purple, lavender, pink, or pearl cap): collect early to prevent clotting
- Heparin tubes (green cap): collect after EDTA tubes
- Any other additive specimens: collect after heparin tubes
- Serum (red or gold cap): collect last, as blood starts to clot immediately
General Procedure for Dermal Puncture
- Introduce yourself and identify the patient using at least two methods
- Position the patient sitting or lying down, with their hand below heart level
- Wash hands and don gloves
- Assemble equipment: gloves, isopropyl alcohol swabs, adhesive bandage, gauze, lancet, and microcollection tubes
- Check the warmth of the hand chosen and identify the site (middle or ring finger for adults and children over 1 year)
- Perform the dermal puncture and collect blood
Heel Stick Procedure for Capillary Blood Collection
- When performing a heel stick on an infant, choose a lancet that punctures the skin to a depth of 0.65 mm if the child's weight is equal to or less than 1 kg.
- A common size used for infants is a 1 mm depth lancet, and never use a lancet that goes deeper than 2 mm.
- Position the patient supine, if possible, and check with the nurse or provider for any restrictions on positioning.
Site Selection and Preparation
- The best sites for a heel stick are the lateral or medial sides of the heel.
- The skin between the lateral and medial sides should be considered a secondary site.
- Avoid using the back of the heel, as it has too little skin/tissue and a lancet puncture can damage the bone.
- Do not use a site that was recently used or has a hematoma or scratch.
Blood Collection and Processing
- Apply the heel warmer for 3 to 5 minutes.
- Wash your hands and wear gloves.
- Cleanse the site and make the puncture.
- Gently squeeze the heel to collect blood, but avoid squeezing for a long time or using excessive pressure.
- Wipe away the first drop of blood and collect the sample in a microcollection tube.
- If the flow of blood stops, wipe away any surface clots with a gauze pad and stop squeezing the heel.
Capillary Blood Collection Order
- The order of the draw is important for dermal punctures to ensure the sample is collected in an order that has the least negative effect on the blood test.
- The CLSI order of the draw for capillary collection is:
- Blood gas collections
- Purple, lavender, pink, or pearl cap tubes (EDTA)
- Green cap tubes (heparin)
- Any other additive specimens
- Serum (red or gold cap tubes)
Post-Collection Procedures
- Apply pressure to the puncture site with a gauze pad for several minutes to stop bleeding.
- Label every specimen before leaving the patient's bedside.
- Observe for any complications and collect all garbage from the area.
- Remove gloves and wash hands.
- Thank the patient.
This quiz covers the steps involved in collecting blood samples, including preparing the patient, filling tubes, and caring for the puncture site.
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