Capillary PunctureCapillary Puncture• AKA: capillary, dermal or skin AKA: capillary, dermal or skin

puncturepuncture• Useful for pediatric patients to avoid Useful for pediatric patients to avoid

iatrogenic anemiaiatrogenic anemia

Capillary Puncture Capillary Puncture EquipmentEquipment

• LancetLancet– Sterile and disposableSterile and disposable– Retractable bladeRetractable blade– Either finger or heelEither finger or heel

• Micro-collection containers (microtubes)Micro-collection containers (microtubes)– Used to collect tiny amounts of bloodUsed to collect tiny amounts of blood

• Microhematocrit tubesMicrohematocrit tubes– Manual HCTManual HCT

• CBG collection tubesCBG collection tubes– Capillary blood gas specimensCapillary blood gas specimens

Compositions of Capillary Compositions of Capillary SpecimensSpecimens

• Mixture of arterial, venous, and capillary blood Mixture of arterial, venous, and capillary blood plus interstitial fluid and intracellular fluidplus interstitial fluid and intracellular fluid

• Reference values different than venipuncture Reference values different than venipuncture specimensspecimens

• Potassium levels falsely elevated with tissue fluid Potassium levels falsely elevated with tissue fluid contamination or hemolysis of specimencontamination or hemolysis of specimen

Indications for Capillary Indications for Capillary PuncturePuncture

• Micro volume to avoid anemiaMicro volume to avoid anemia• Veins need to be reserved for chemotherapyVeins need to be reserved for chemotherapy• Patients with extensive burnsPatients with extensive burns• Patients that clot easilyPatients that clot easily• Several unsuccessful venipuncturesSeveral unsuccessful venipunctures• Patients with blenophobiaPatients with blenophobia• No accessible veinsNo accessible veins• Infants and childrenInfants and children• POCT testing: CBC, cholesterol & glucose POCT testing: CBC, cholesterol & glucose

screening screening

TESTS NOT DONE BY TESTS NOT DONE BY SKIN PUNCTURESKIN PUNCTURE

• Blood culturesBlood cultures• Erythrocyte Sedimentation RateErythrocyte Sedimentation Rate• Coagulation studiesCoagulation studies• Tests requiring large volume of sera or plasmaTests requiring large volume of sera or plasma• Patients where capillary puncture is not Patients where capillary puncture is not

appropriate:appropriate:– Dehydrated patientsDehydrated patients– Patients with poor circulation to extremities from shockPatients with poor circulation to extremities from shock

Order of DrawOrder of Draw• Blood gasBlood gas• EDTA specimens (hematology)EDTA specimens (hematology)• Other additive specimensOther additive specimens• Serum specimensSerum specimens

Site SelectionSite Selection• Adults and children older than 1 yearAdults and children older than 1 year

– Palmar surface of the end segment of Palmar surface of the end segment of the middle or ring fingerthe middle or ring finger

– Use non-dominate handUse non-dominate hand– In central fleshy portion slightly to the In central fleshy portion slightly to the

side of centerside of center– Perpendicular to grooves of fingerprintPerpendicular to grooves of fingerprint– NEVER use fingers or earlobes of NEVER use fingers or earlobes of

newborns or infants under 1 year!!newborns or infants under 1 year!!

Site SelectionSite Selection• InfantsInfants

– Do not to exceed 2.0 mm- Do not to exceed 2.0 mm- • Puncturing of bone can lead to osteomyelitisPuncturing of bone can lead to osteomyelitis

– Stick perpendicular on the most medial or Stick perpendicular on the most medial or most lateral portion of the plantar surface of most lateral portion of the plantar surface of the heelthe heel• Calcaneous may be just 2 mm below skinCalcaneous may be just 2 mm below skin

– Warm site before punctureWarm site before puncture• Use warm water or heel warmer deviceUse warm water or heel warmer device• Do not exceed 42 degrees CDo not exceed 42 degrees C

SKIN PUNCTURESSKIN PUNCTURES• Cleaning the siteCleaning the site

– 70% isopropyl alcohol70% isopropyl alcohol– Never use povidone-iodine as it interferes with some testsNever use povidone-iodine as it interferes with some tests

• Always wipe away first drop of blood Always wipe away first drop of blood – Contains fluid plasma, tissue extracts, and possibly alcohol Contains fluid plasma, tissue extracts, and possibly alcohol

residue residue • Do Not Squeeze (or “milk”) SiteDo Not Squeeze (or “milk”) Site

– Results in hemolysis & increased tissue fluid contaminationResults in hemolysis & increased tissue fluid contamination• Do not use a “scooping” motion against the surface Do not use a “scooping” motion against the surface

of the skinof the skin– Activates platelets causing them to clumpActivates platelets causing them to clump– Can cause hemolysisCan cause hemolysis

SKIN PUNCTURESSKIN PUNCTURESLabeling of specimens:Labeling of specimens:Patient name & ID numberPatient name & ID numberTime & Date of collectionTime & Date of collectionPBT initialsPBT initials

BLOOD GASES - BLOOD GASES - NEONATESNEONATES

• Source of blood is from catheter in Source of blood is from catheter in umbilical artery umbilical artery

• Procedure is the responsibility of Procedure is the responsibility of the pediatric unit or neonatal the pediatric unit or neonatal intensive care unit.intensive care unit.

Neonatal Bilirubin Neonatal Bilirubin CollectionsCollections

• Used to detect and monitor increased bilirubin Used to detect and monitor increased bilirubin levels in newbornslevels in newborns

• High levels result in jaundiceHigh levels result in jaundice• Breaks down in presence of lightBreaks down in presence of light• Collected by heel stickCollected by heel stick• Must be protected from hemolysis and lightMust be protected from hemolysis and light

– Use amber colored micro-collection containerUse amber colored micro-collection container– Turn off UV lamp in cribTurn off UV lamp in crib

Newborn Screening TestsNewborn Screening Tests• Test for:Test for:

– PKU-phenylketonuria-a genetic disorder PKU-phenylketonuria-a genetic disorder – HypothyroidismHypothyroidism– GalactosemiaGalactosemia– Cystic FibrosisCystic Fibrosis

• Blood spot collection:Blood spot collection:– Heel stick blood collected by absorption onto 5 circles on a Heel stick blood collected by absorption onto 5 circles on a

special paperspecial paper– Paper must not touch heelPaper must not touch heel– Blood must completely fill circles from one side of the paper Blood must completely fill circles from one side of the paper

onlyonly– Contaminants include: alcohol, formula, lotion, power, Contaminants include: alcohol, formula, lotion, power,

urineurine

BLOOD SMEARSBLOOD SMEARS• Wipe away first drop of blood, make smear Wipe away first drop of blood, make smear

immediately.immediately.• EDTA Blood Tube: EDTA Blood Tube:

– Make blood smears within 1 hour of collectionMake blood smears within 1 hour of collection– May be stored at 4 degrees celsius (refrig.) overnight May be stored at 4 degrees celsius (refrig.) overnight

for CBCfor CBC– For smears: 3 - 4 hours after standing at room For smears: 3 - 4 hours after standing at room

temperature.temperature.• Acceptable smear: Acceptable smear:

– Blood covers half to three-fourths of the slide with a Blood covers half to three-fourths of the slide with a feathered edgefeathered edge

– Has no holes, lines, or jagged edgesHas no holes, lines, or jagged edges

BLOOD SMEARSBLOOD SMEARSSmear fixativeSmear fixative - methyl alcohol for 1 - methyl alcohol for 1

minuteminuteManual wedgeManual wedge - spreader/pusher - spreader/pusher

slide; 30 degree angleslide; 30 degree angleSpinner - automated cell counterSpinner - automated cell counter