A sterile, disposable, sharp-pointed or bladed instrument that either punctures or makes an incision in the skin to obtain capillary blood specimens for testing. Must have OSHA required safety features
Lancet
Small plastic tubes used to collect tiny amounts of blood obtained from capillary punctures (a.k.a. bullets).
Microcollection containers or microtubes
When venous blood is obtained by syringe and put into a microcollection container what should you do?
The specimen must be labeled as venous blood because it may have different reference ranges.
Disposable, narrow-bore plastic or plastic-clad glass capillary tubes that fill by capillary action are called what?
Microhematocrit tubes
What are microhematocrit tubes used for?
Manual hematocrit (Hct), also called packed cell volume (PCV)
Capillary Blood Gas (CBG) tubes are normally coated with this anticoagulant.......
Sodium Heparin
What is a stirrer called in a CBG tube?
Fleas
What is the purpose of a magnet with the CBG tube?
Mix the specimen
Capillary blood more closely resembles what type of blood arterial or venous?
Arterial because it enters the capillaries under pressure
Capillary specimens are a mixture of what 5 things?
Arterial, venous and capillary blood along with interstitial fluid and intracellular fluid
What is interstitial fluid?
Fluid in the tissue spaces between the cells
What is intracellular fluid?
Fluid within the cells
Is the concentration of glucose higher or lower in capillary blood?
Higher
Is total protein (TP), calcium (Ca2), and potassium (K+) concentrations higher or lower in capillary blood?
Lower
What may cause potassium values to be falsely elevated in skin puncture specimens?
Fluid contamination or hemolysis of the specimen
What are some indications for capillary puncture in an adult or older child?
Available veins are fragile or must be saved for other procedures.
Several unsuccessful venipunctures have been performed and the test can be collected by capillary puncture
Patient has thrombotic or clot-forming tendencies
Patient is apprehensive or has
Capillary puncture is the preferred method of obtaining blood from infants and very young children for the follow reasons:
Small blood volume. Removing quantities of blood can lead to anemia.
Large quantities removed rapidly can cause cardiac arrest. Life is threatened if more than 10% is removed at once or over a short period.
It is difficult and may damage veins and surroun
Tests that cannot be collected by capillary puncture are what ?
Erythrocyte sedimentation rate methods, coagulation studies that require plasma, blood cultures and tests that require large volumes of serum or plasma.
Order of draw for capillary puncture?
Slide first
Blood gas specimens (CBGs)
EDTA (lavender, hematology)
Other additive specimens (CBC, chemistry)
Serum specimens (red)
Where is the CLSI recommended site for capillary puncture on adults and children older than 1?
The palmar surface of the distal or end segment of the middle or ring finger of the nondominant hand. Should be in the central, fleshy portion of the finger, slightly to the side of center and perpendicular (across) the groves in the whorls.
What is the spiral pattern on your fingertip called?
Whorls
Why: Do not puncture fingers of infants and children under 1 y.o.?
The amount of tissue between the skin surface and bone is so small that bone injury is very likely.
Why: Do not puncture finger on the same side as a mastectomy without consultation with the patient's physician?
The arm on the same side as a mastectomy is susceptible to infection, and effects of lymphostasis can lead to erroneous results.
Why: Do not puncture parallel to the grooves or lines of the fingerprint (whorls)?
A parallel puncture will allow blood to run down the finger rather than form a rounded drop, and make collection difficult.
Why: Do not puncture the fifth or little (pinky) finger?
The tissue between skin surface and bone is thinnest in this finger, and bone injury is likely.
Why: Do not puncture the index finger?
It is usually more calloused and harder to puncture. It is also more sensitive so the puncture can be more painful; and, because that finger is typically used more, a patient may notice the pain longer.
Why: Do not puncture the side or very tip of the finger?
The distance between the skin surface and the bone is half as much at the side and tip as it is in the central fleshy portion of the end of the finger.
Why: Do not puncture the thumb?
It has a pulse, indicating an artery in the puncture area, and the skin is generally thicker and more calloused, making it difficult to obtain a good specimen.
Osteomyelitis
Inflammation of the bone marrow and adjacent bone
Osteochondritis
Inflammation of the bone and cartilage
What depth will provide adequate blood flow in a newborn with risking bone injury?
2.0mm or less
According to CLSI the only safe areas for heel puncture on a newborn is where?
Plantar surface of the heel, medial to an imaginary line extending from the middle of the great toe to the heel or lateral to an imaginary line extending from between the fourth and fifth toes to the heel.
If you warm the site for capillary puncture the specimen is described as what?
Arterialized because of the increase in arterial blood flow.
Why: Do not puncture any deeper than 2.0mm?
Deeper punctures risk injuring the bone, even in the safest puncture areas
Why:Do not puncture areas between the imaginary boundaries?
The calcaneus may be as little as 2.0mm deep in this area.
Why: Do not puncture in the arch and any areas of the foot other than the heel?
Arteries, nerves, tendons, and cartilage in these areas can be injured
Why: Do not puncture severely bruised areas?
It is painful, and impaired circulation or byproducts of healing process can negatively affect the specimen
Why: Do not puncture the posterior curvature of the heel?
The bone can be as little as 1mm deep in this area
Why: Do not puncture through previous puncture sites?
This can be painful and can spread previously undetected infection
Why: Do not puncture a site that is swollen?
Excess tissue fluid in the area could contaminate the specimen
Why can we not use povidone-iodine to clean skin puncture sites?
It greatly interferes with a number of tests, most notably bilirubin, uric acid, phosphorus and potassium
Why do we wipe away the first drop of blood?
It is typically contaminated with excess tissue fluid and may contain alcohol residue that can hemolyze the specimen. There have been reports of isopropyl alcohol contamination causing errors in blood glucose testing.
Why do we not use a scooping motion against the surface of the skin to collect blood?
Activates platelets, causing them to clump and can also hemolyze the specimen
What causes increased bilirubin levels in newborns?
Overproduction or impaired excretion of bilirubin
Overproduction of bilirubin occurs from accelerated red blood cell hemolysis associated with what disease?
Hemolytic disease of the newborn (HDN)
A transfusion may be needed if bilirubin levels increase at a rate equal to or greater than what?
5.0mg/dL per hour or when levels exceed 18.0 mg/dL
How are bilirubin specimens collected?
Heel puncture
Collected in amber-colored microcollection containers
Specimens should be collected as close as possible to the time requested
Careful to avoid hemolysis which could falsely decrease bilirubin results
State mandated testing of newborns for the presence of certain genetic, metabolic, hormonal and functional disorders is called what?
Newborn/neonatal screening (NBS)
The March of Dines recommends tat all newborns be screened for how many specific disorders?
29
What 4 conditions are screened for by law?
Phenylketonuria (PKU)
Hypothyroidism
Galactosemia (GALT)
Cystic Fibrosis (CF)
Phenylketonuria
A genetic disorder characterized by a defect in the enzyme that breaks down the amino acid phenylalanine.
Hypothyroidism
Insufficient levels of thyroid hormones.
Galactosemia
Lack of the enzyme needed to convert the milk sugar galactose into glucose needed by the body for energy.
Cystic Fibrosis
Genetic disorder caused by one or more mutations in the gene that directs a protein responsible for regulating the transport of chloride across cell membranes. Primarily affects the lungs and pancreas. Causes the body to produce thick, stick mucus secreti
How do you perform blood spot collection?
Heel puncture
Wipe away first drop of blood
A large drop of free-flowing blood is applied to the center of the first circle.
Touch the paper to the blood. DO NOT touch the surface of the heel.
Completely fill the circle on both sides of the paper
Circles
What do you do with the blood spot collection after it is collected?
Allow to air-dry in an elevated, horizontal position away from heat or sunlight.
Specimens should not be hung to dry or stacked together before, during, or after the drying process,
What is a blood film or smear (a drop of blood spread thin on a microscope slide) used for?
Manual differential (diff)
Blood smears prepared from EDTA specimens should be made within how many hours?
1 hour
What is the correct angle for making a blood smear?
30 degrees
The thinnest area of a properly made smear is called what?
Feather
Blood smears are considered biohazardous or infectious until when?
Until they are stained or fixed
What is a thick blood smear used for?
Detect malaria