Phlebotomy Ch 10 Capillary Puncture Flashcards
What is a lancet/incision device?
Lancet/Incision Devices
- Sterile, disposable, sharp-pointed or bladed instrument
- Punctures or cuts skin to obtain capillary blood specimen
- Designed for either finger or heel puncture
Are some lancets designed specifically for finger punctures?
Yes.
What is an important required lancet safety feature?
Permanently retractable blade to reduce risk of accidental sharp injury.
Are some lancets designed specifically for heel punctures for infants? What do they do differently?
Some are designed specifically for heel punctures for infants
These devices don’t puncture with a needle in and out but take a slice of infants heel
What features do micro-collection containers/microtubes have?
Small plastic tubes used to collect tiny amounts of blood from capillary punctures
Some come with narrow capillary tubes attached
Have color-coded bodies or stoppers & markings for min/max fill levels
How is micro collection useful for pediatric patients?
Capillary specimen collection is especially useful for pediatric patients in whom removal of larger quantities of blood by venipuncture can have serious consequences.
What are microhematocrit tubes and sealants? What are they used for/
Microhematocrit Tubes & Sealants
Disposable, narrow-bore plastic or plastic-clad glass tubes
Fill by capillary action & hold 50 to 75 uL
Used primarily for hematocrit determinations
One end of tube is sealed w. plastic or clay sealants
What are capillary blood gas equipment (CBG)?
Capillary Blood Gas Equipment (CBG)
- CBG collection tubes: narrow-bore plastic capillary tubes
- Stirrers: metal filings or bars inserted into tube to mix
- Magnet: used for mixing, in conjunction w. stirrer
- Plastic caps: used to seal tubes
Name capillary puncture equipment?
Lancet/incision devices Finger Puncture Lancets Heel Puncture Lancets Microcollection / Microtubes Microcollection Containers Microhematocrit Tubes & Sealants Capillary Blood Gas Equipment (CBG) Microscope Slides Warming Devices
What is the composition of capillary specimens?
- Mixture of arterial, venous, and capillary blood.
- Interstitial and intracellular fluid.
- More closely resembles arterial blood than venous blood.
How do capillary reference values differ from venous values?
Capillary reference values may differ from venous values
Glucose concentrations are higher in capillary blood
Bilirubin, Total protein (TP), calcium (Ca2+), and potassium (K+) concentrations are lower in capillary blood
What are some reasons to perform (indications) capillary puncture in older children and adults?
Available veins are fragile or must be saved for other procedures
Several unsuccessful venipunctures have been performed
Patient has clot-forming tendencies
Patient is apprehensive or has an intense fear of needles
There are no accessible veins (IVs in both arms, scars, burns)
For POCT procedures such as glucose monitoring
What are reasons for performing capillary puncture in infants and young children?
Small blood volume & risk of anemia
Risk of cardiac arrest when large quantities of blood are removed
Venipuncture is difficult & may damage veins & surrounding tissues
Puncturing deep veins can cause hemorrhage, venous thrombosis, infection, & gangrene
Risk of injury due to restraint needed for venipuncture
Capillary blood is preferred specimen for some tests (NBS)
What are some tests that cannot be collected by capillary puncture?
- Most erythrocyte sedimentation rate methods
- Coagulation studies that require plasma specimens
- Blood cultures
- Tests that require large volumes of serum or plasma
What is the CLSI order of draw for capillary punctures?
CLSI Order of Draw Blood gas specimens (CBGs) EDTA specimens Other additive specimens Serum specimens
NOTE: NBS should be collected separately from a separate puncture