1 Flashcards
———— specimens are a mixtures of arterial, venous, and capillary blood along with interstitial fluid and intracellular fluid from surrounding tissues.
Capillary
These are fluid in the tissue spaces between the cells
Interstitial fluid
These are fluid within the cells
Intracellular fluid
What kind or type of blood enters the capillaries under pressure?
Arterial blood
Capillary blood contains a ——– (higher, lower) proportion of arterial blood than venous blood
higher
Warming causes ———- (increases, decreases) arterial flow into the area
increases
Capillary Puncture Equipment
- Lancets/incision devices
- Microcollection containers
- Microhematocrit tubes and sealants:
- Red or green band: Heparinated tube - Blue band: Non-additive tube
Capillary puncture can be an appropriate choice for adults and older children under what circumstances?
- Available veins are fragile or must be saved for other procedures such as chemotherapy
- Several unsuccessful venipunctures have been performed and the requested test can be collected by capillary puncture
- The patient has thrombotic or clot-forming tendencies
- The patient is apprehensive or has an intense fear of needles
- There are no accessible veins (e.g., the patient has IV’s in both arms or the only accepted sites are in scarred or burned areas).
- To obtain blood for POCT procedures such as glucose monitoring
Capillary puncture is the preferred method of obtaining blood from infants and very young children for what reasons:
- Infants have a small blood volume; removing quantities of blood typical of venipuncture or arterial puncture can lead to anemia. According to studies, for every 10 mL of blood removed, as much as 4 mg of iron is also removed
- Large quantities removed rapidly can cause cardiac arrest. Life is threatened if more than 10% of a patient’s blood volume is removed at once or over a short period.
- Obtaining blood from infants and children by venipuncture is difficult and may damage veins and surrounding tissues
- Puncturing deep veins can result in hemorrhage, venous thrombosis, infection and gangrene
- An infant or child can be injured by the restraining method used while performing a venipuncture
- Capillary blood is the preferred specimen for some tests, such as newborn screening tests
Concentration of glucose is normally ——— (higher, lower) in capillary blood specimens
higher
Total ——–, ———-, and ———-, concentrations are lower in capillary blood specimen
protein, calcium, and potassium
These values are normally lower in properly collected skin puncture specimens, levels may be falsely elevated if there is tissue fluid contamination or hemolysis of the specimen
Potassium
What are some tests that cannot be collected by capillary puncture
- erythrocyte sedimentation rate methods
- coagulation studies that require plasma specimens
- blood cultures
- tests that require large volumes of serum or plasma
What is usually the preferred site for capillary testing in an adult patient?
finger
What are only used in pediatric and neonatal patients?
sides of the heel
What are sometimes used in mass screening or research studies?
Ear lobes
What are some basis for selection of a site for capillary sampling in a pediatric patient?
Age and Weight of the patient
Heel Puncture Precautions
Do not puncture any deeper than ——–.
2.0 mm
Heel Puncture Precautions
Do not puncture in the —– and any areas of the foot other than the heel. Arteries, nerves, tendons, and cartilage in these areas can be injured
arch
Heel Puncture Precautions
Do not puncture the ——– (posterior, anterior) curvature of the heel. The bone can be as little as —— deep in this area.
posterior; 1mm
Puncturing the skin releases tissue —–, which activates the coagulation process in blood drops.
Thromboplastin
Why are hematology specimens collected first?
They are collected first because they are the most affected by the clotting process
What specimens are collected last?
Serum
Why are serum specimens collected last?
They are collected last because they are supposed to clot
CLSI order of draw for capillary specimens:
- Blood gas specimens (CBG’s)
- EDTA specimens
- Other additive specimens
- Serum specimens
