(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