(M) Lesson 3: Capillary Puncture Flashcards
→ aka skin puncture, dermal puncture, or microsampling
→ sample is addressed as capillary, skin puncture, or dermal specimen
Capillary Puncture
T or F: Capillary blood is a mixture of arterial, venous, and capillary blood with interstitial, and intracellular fluid
True
T or F: Capillary blood has a higher proportion of venous blood than arterial blood
False
T or F: Reference values for capillary blood are different from venous blood
True
T or F: Glucose is commonly lower while total protein, calcium, and potassium are commonly higher in capillary blood than in venous blood
False (glucose is higher while the rest are lower)
Which puncture site is most common for infants?
Plantar heel surface
What fingers are preferred in capillary puncture for adults?
3rd and 4th
What finger has a pulse hence why is it not a preferred site?
Thumb
Which finger is commonly calloused hence why is it not a preferred site?
Index
Which finger is in close proximity to a bone hence why is it not a preferred site?
Pinky
T or F: Capillary puncture can be used for blood cultures
False (needs a large volume of blood)
T or F: Capillary puncture can be used for coagulation studies
False (requires the usage of a sodium citrate tube)
T or F: Lancets are sterile and disposable
True
This equipment punctures and makes incisions in the skin
Lancets/Incision Devices
What is the standard lancet length?
1.75mm
What is the incision depth for infants and children?
Less than 2mm
What is the incision depth for adults?
Less then 2.5mm
What is the standard skin to bone/cartilage distance?
1.5mm - 2.4mm
→ an alternative incision device
→ it vaporizes water and makes a small hole in the capillary bed without cauterizing delicate capillaries
Laser lancet
T or F: Laser lancets are commonly used for the fingers of adults and children greater than 5 years old
True
T or F: Laser lancets can be used on children less than 5 years old
True (but you need physician discretion first)
T or F: Laser lancet inserts can be reused
False
→ aka microtubes—called as “bullets” because of their size and shape
→ used to collect tiny amounts of blood
→ has color coded bodies or stoppers
Microcollection containers
What is the fill range for microcollection containers?
250-500 microliters
T or F: Venipuncture-obtained blood can be put in microcollection tubes incase of a short-draw
True
T or F: Serum specimen comes first in the order of draw
False (hematology specimen first to avoid quick clotting because the skin releases tissue thromboplastin—activates coagulation in blood drops)
→ disposable and narrow-bore or plastic-clad glass tubes
→ aka capillary tubes or “capillet”
→ used for manual hematocrit testing/packed cell volume
Microhematocrit tubes
What is the fill range of microhematocrit tubes?
50-75 microliters
A red/green microhematocrit tube is coated with what?
Ammonium Heparin
Red microhematocrit tubes can collect samples where?
Directly from the puncture site
Blue microhematocrit tubes are coated with what?
Nothing (plain)
Blue microhematocrit tubes collect samples from where?
EDTA tubes
T or F: 1/2 of the microhematocrit tube should be filled
False (3/4)
→ plastic or clay
→ seals one end of the microhematocrit tube
Sealant
→ long-thin narrow bore tubes
→ 100mm in length; 100uL in capacity
→ has color coded bands (usually green—heparin)
Capillary Blood Gas Equipment
A small metal bar aka “flea” that aids in mixing the anticoagulant for CBG collection
Stirrer
This mixes the specimen with the metal stirrer (back and forth along the tube length)
Magnet
This seals CBG tubes and maintains its anaerobic condition
Plastic Caps
→ for blood films for hematology determination
→ may or may not come with a frosted end where patient into is written
Microscopic slides
How many times does a warming device increase blood flow to the puncture site?
7 times
What is the maximum temperature for warming devices?
42 degrees Celsius
T or F: Infants should lie facing down when performing capillary puncture
False (supine; lying face up)
T or F: Pain fibers decrease in abundance below the capillary bed
False (increase)
T or F: Non-dominant hands have less callouses than the dominant hand
True
T or F: Capillary puncture should be performed on the 2nd and 3rd finger of the non-dominant hand
False (3rd and 4th)
T or F: Puncture site should be parallel to the grooves of the fingerprints
False (perpendicular because blood can travel down the finger if done parallel)
What does osteomyelitis mean?
Bone imflammation
What does osteochondritis mean?
Bone cartilage inflammation
T or F: Heel punctures should be done less than 2mm
True
Warm specimen is also called as what?
Arterialized capillary blood
How long is the application for a warming device?
3-5 minutes
How many fingers should you grasp for pediatric patients when performing capillary puncture?
3-4 fingers
When performing heel puncture, at what degree should the incision be made to create a gap puncture (opens when pressure is applied)?
90-degrees
T or F: You can use the first drop of blood as a sample
False (contains interstitial fluid and alcohol)
In what direction should you wipe the first drop in order to encourage blood flow?
Downwards
In what direction should you fill the tubes in order to encourage blood flow?
Downward
T or F: Do not squeeze or “milk” the site as hemolysis and tissue fluid contamination can occur
True
How many times should you invert the microcollection tubes?
8-10 times
T or F: You cannot tap microtubes after filling
False
T or F: A microhematocrit tube will automatically fill by capillary action
True
T or F: A diagonal position above the blood drop should be maintained when using microhematocrit tubes
False ( vertically or horizontally)
T or F: Microcollection containers are to be held upright just below the blood drop
True
T or F: You can use a scooping motion against the surface of the skin as blood flows down the finger
False (activates platelet action resulting in clot formation and hemolysis)
T or F: Microhematocrit tubes can be directly labeled
False (place in a non-additive tube or aliquot tube, then label)
How long should the bandage be kept on after the procedure?
15 minutes
T or F: You can apply bandages even for infants
False (it is a choking hazard)
This special test is rarely collected in adults and more preferably for infants
Capillary Blood Gas
T or F: Capillary blood gas specimen is transported via a warm environment
False (cold; sometimes even with ice)
This test is done as detection and monitoring of increased bilirubin levels due to overproduction or impaired excretion
Neonatal bilirubin collection
T or F: High levels of bilirubin can be caused by heme production from RBC hemolysis
True
T or F: High levels of bilirubin = jaundice but low risk for permanent brain damage
False (high risk for brain damage)
T or F: Jaundiced patients are exposed to UV light to decrease bilirubin levels as they are photosensitive
True
Neonatal bilirubin collection is done in which site for infants?
Plantar heel surface
What color are the microcollection containers used in neonatal bilirubin collection?
Amber
This is the mandated testing of newborns for the presence of certain genetic (inherited), metabolic (chemical changes within living cells), hormonal, infectious, and functional disorders that can cause handicaps and abnormalities if not treated early
Newborn screening/Neonatal screening
Neonatal screening is ideally performed on babies how many days old?
1-2 days
T or F: Early collection for infants less than 24 hours can still yield accurate results
False
T or F: Neonatal screening is collected separately from the microsampling tubes
True
→ few drops obtained from heel puncture
→ blood drops adsorbed onto circles printed on a special type of filter paper (blood circles)
Blood Spot Collection
How many diseases can blood spot collection detect?
Around 30
T or F: For blood spot collection, you can touch the paper to the heel surface
False
What can multiple drops in the circles lead to?
Layering of blood cells
T or F: Neonatal screening specimen can be collected after blood transfusion
False
T or F: Blood spot filter papers can air dry in an elevated, vertical position away from heat or sunlight
False (horizontal)
What can happen if the blood spot filter paper is hung or stacked together?
Blood migration and cross contamination
How many smears are always prepared for routine blood films?
2
T or F: Blood films are only prepared manually
False (can be obtained from EDTA tubes)
T or F: Blood smears from EDTA specimens should be made after 1 hour of collection
False (within; to eliminate cell distortion caused by the anticoagulant)
T or F: Routine blood smears are to be performed before the micrsampling tubes
True
How many mm should the blood drop diameter be in routine blood smears?
1-2
At what angle must the spreader slide be held?
30 degrees
T or F: You need to wait for the first smear to dry before proceeding to use it as a spreader slide
True
T or F: Frosted slides can have the labels written on them
True
How many minutes should the EDTA tube be mixed before performing blood smears?
2 minutes
T or F: Smears are considered non-infectious until they are stained or fixed
False
An acceptable smear covers how much of the slide surface?
1/2 to 3/4
In which part of the slide is a differential count performed?
Along the feathery edge
Thick smears indicate what?
Stacked cells
This smear is used in malaria detection (plasmodium species—vector-borne)
Thick smears
T or F: Suspected malaria test requests only require a thick smear
False (comparison of both thin and thick smear)
T or F: Thin smears detect the species of malaria present in the patient while thick smears only confirm if a patient has malaria
True
T or F: Thick smears cannot be ordered as STAT
False (you can; collect before onset of fever and chills)
How long should a thick blood drop dry before staining?
2 hours
What is the stain used for thick smears?
Giemsa