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PCML112 | PRINCIPLES OF MEDICAL TECHNOLOGY 2 (LECTURE)
Module 7: CAPILLARY PUNCTURE EQUIPMENT AND PROCEDURE
TABLE OF CONTENTS
1. INTRODUCTION: Capillary Puncture
2. Composition of Capillary Blood Specimen
3. Equipment
4. Capillary Puncture Steps
i.
Order of Draw (Capillary Puncture)
5. Cause of Hemolysis
6. Specimen Collection for Special Tests that
involves Capillary Puncture
i.
Thick and Thin Blood Smear
Preparation
ii.
Capillary Blood Gas
iii.
Neonatal Bilirubin
iv.
Newborn Screening
7. Newborn Screening Program in the Philippines
8. NBS Panel in the Philippines
i.
NBS
ii.
ENBS (Expanded NBS)
CAPILLARY PUNCTURE
 aka Dermal Puncture
 method that uses lancet to make a small
incision into the capillary bed of the skin to
obtain small volume of blood specimen
 Method of Choice for collecting blood from
infants and children below 2 y/o
 Used on adults and older children, under the
ff circumstances:
 Burned or scar patients
 Patient receiving chemotherapy
 Patient with thrombotic tendencies
(easily clots blood)
 Geriatric with fragile veins
 Patient with inaccessible veins
 Obese patients
 Apprehensive patients
 Patients requiring home glucose
monitoring (POCT)
 Do not use on the following tests:
 Erythrocyte Sedimentation Rate
(requires large amount of blood)
 Blood cultures (capillary puncture is
prone to bacterial inf.)
 Coagulation tests (needs blood-toanticoagulant ratio; light blue top w/
9:1 ratio)
COMPOSITION OF CAPILLARY BLOOD
SPECIMEN



These blood specimen that comes from
capillary, arterioles, and venules.
Composition:
a. Arterial blood (more arterial blood than
venous blood because of arterial
pressure)
- bright red blood; oxygenated
b. Venous blood
- dark red blood; deoxygenated
c. Interstitial fluid
- fills spaces around the cell
d. Intracellular fluid
- found inside the cells; facilitates fluid
movement in membrane
Concentration differences:
a. Glucose: higher than venous blood
b. Potassium, total Protein and Calcium:
lower than venous blood
EQUIPMENT
CAPILLARY BLOOD SAMPLING DEVICES:
 LANCETS - Sterile, sharp instrument that are
intended for one-time use only.
 LASER LANCET - produces a small hole in the
skin by vaporizing water in the skin
 Eliminates the risk of sharp injury
 1-2 mm penetration
 Collects up to 100uL of blood
MICROSAMPLE CONTAINERS:
 MICROCOLLECTION TUBES (MICROTUBES) –

Small plastic tubes used to hold blood
specimen (up to 600 uL) collected in
capillary puncture.
 May be plain or with additives
 Some have narrow capillary tube
CAPILLARY TUBES (aka MICROHEMATOCRIT
TUBES) -
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PCML112 | PRINCIPLES OF MEDICAL TECHNOLOGY 2 (LECTURE)
Module 7: CAPILLARY PUNCTURE EQUIPMENT AND PROCEDURE
-
Small glass tubes used to collect capillary
blood for the purpose of microhematocrit
test (approx. 50-75 uL).
 Ends are sealed with clay sealant or
plastic plug
 2 Types (color-coded):
a. Plain (blue band) - used when
test is performed on blood from
pre-collected EDTA blood.
b. Heparinized (red band) - used
when test is performed on blood
collected from dermal puncture ;
w/ Heparin which is an
anticoagulant
ADDITIONAL SUPPLIES:
1. MICROSCOPE SLIDES - used for blood
films/smear for hematology/parasitology
determinations
2. WARMING DEVICES - used to warm the
puncture site to increase blood flow by 7folds
 HEEL WARMER - disposable packets
containing sodium thiosulfate and
glycerin that produce heat when
mixed together by gentle squeezing.
 Warm washcloths/towel
3. CAPILLARY BLOOD GAS EQUIPMENT
1.
2.
3.
4.
5.


Special equipment used for collecting
capillary blood gas specimens
- Contains: collection tubes, stirrers,
magnet, and plastic caps
CAPILLARY PUNCTURE STEPS
STEP 1-5
Review and check accession test request
Approach, Identify and Prepare the patient
Verify diet restriction and latex sensitivity
Sanitize hands and put on gloves
Position the patient:
 Patients arm should be placed on
firm surface
 Arms extended, palm facing up
 Heel puncture - patient in supine
position and foot in not lower than
torso
STEP 6: SELECT PUNCTURE SITE
General criterion: site should be pink, normal
in color, and warm.
Heel Puncture Site
 Used on infants (≤ 1y/o) (not yet
walking)
 For infants: incision site should be
less than 2.0 mm deep
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PCML112 | PRINCIPLES OF MEDICAL TECHNOLOGY 2 (LECTURE)
Module 7: CAPILLARY PUNCTURE EQUIPMENT AND PROCEDURE

Acceptable Area: Lateral or Medial
Plantar area
- Distance between skin and calcaneus
is the greatest
 Finger Puncture Site
 Used on adults and children (≥ 1y/o)
 Acceptable area: Central palmar
area of third or fourth finger of
nondominant hand
STEP 7: WARMING THE SITE
 Dilates blood vessels and increase arterial
blood flow for up to seven-folds.
 Warm washcloth/towel (42 C) for 3-5 mins
 Heel warmer - mix the packet to activate
and place on the puncture site for 3-5
minutes
 Warming should not exceed 10 minutes ²
may alter test results.
- increases arterial blood flow hence,
altering capillary blood composition
that may affect the results
STEP 8: Clean and air-dry the site
 Use antiseptics (ex. 70% isopropanol)
STEP 9: Prepare equipment
STEP 10: PUNCTURE THE SITE (quick and deep)
 Incision depth: 2 - 2.5 mm
 HEEL PUNCTURE:


Hold heel between thumb (at
bottom) and index finger (near the
arch)
 Lancet is positioned in median/lateral
plantar surface of heel
FINGER PUNCTURE:

Finger is held between the
nondominant thumb and index
finger, with the palmar surface facing
up and the finger pointing downward
to increase blood flow.
 Lancet placed flat against central
fleshy part of site
STEP 11: Wipe the first drop of blood
 Contaminated with tissue fluids (can
dilute the blood and may alter the
results)
STEP 12: FILL AND MIX TUBES
 ORDER OF DRAW (Capillary puncture)
 Important as platelet has tendency to
accumulate at the site of wound
ORDER OF DRAW
ADDITIVES
INVERSION/MI
XING
Capillary Blood Gas Heparin
Rotate
between
palms
Blood Smears
N/A (placed N/A
in glass
slides)
Lavender top
EDTA
10
Heparinized
Lithium
10
Heparin
No Inversion if
 Green top
microhemato
 Microhemat
crit tube
ocrit tube w/
red band
Plasma Separator
Lithium
10
Tubes
heparin with
gel
separator
Oxalate/Fluoride
Sodium
10
Tubes
fluoride with
Potassium
oxalate
Serum tube with
Clot
5
additives
activator
Serum tube without N/A
0
additive
Newborn Screening Use
0
spot/filter
cards
STEP 13: Place gauze and apply pressure
 ‡ Keep incision site elevated (so that
the blood flow diminishes)
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PCML112 | PRINCIPLES OF MEDICAL TECHNOLOGY 2 (LECTURE)
Module 7: CAPILLARY PUNCTURE EQUIPMENT AND PROCEDURE
STEP 14: Label specimen and observe proper
handling
STEP 15: Check the site and apply bandage
STEP 16: Disposal of used and contaminated
materials
STEP 17: Transport specimen to the Laboratory
CAUSE OF HEMOLYSIS
 Hemolysis is more frequently encountered in
capillary puncture than in venipuncture.
 Milking - excessive squeezing of puncture
site.
 Newborn have increased RBC and increased
RBC fragility
 Residual alcohol at the puncture site
 Vigorous mixing of microcollection tubes
after collection
SPECIMEN COLLECTION FOR SPECIAL
TESTS






THICK AND THIN BLOOD SMEAR
PREPARATION



Thin blood smear preparation is used to
appearance of blood cells for diagnostic
purposes:
 Blood cell abnormalities
 Identification and differential
quantification of WBC (manually
counting of eosinophils, neutrophils
etc.)
 Platelet estimate count
 Malaria parasite identification
Procedure:
1. Place one drop of blood near one
end of a glass slide
2. Use another slide to spread the
drop of blood into thin smear
3. Air dry then stain.


Thick blood smear preparation is used for
quantitative malaria determination
(counting of the parasite)
Procedure:
1. Place one drop of blood on the
center of the slide
2. Place a drop of water and mix
3. Allow to air dry then stain
CAPILLARY BLOOD GAS
Arterial blood - preferred sample for blood
gas analysis and pH determination
Capillary blood is only used among
newborns and infants.
Arterialize capillary blood by warming the
site prior to collection (40-42 C) for 5minutes
Microcollection tube: Heparinized
Sample are place in ice slurry and
transported to the laboratory immediately.
- ice slurry – prevents changes in pH
and deterioration of blood gases
NEONATAL BILIRUBIN
to determine any liver disorder in infants.
Collected with a heel stick.
BILIRUBIN
 a light sensitive analyte that imparts
dark yellow discoloration in the
blood, skin and eyes.
 decreases concentration w/ presence
of light
 Commonly performed among
newborn
 Bilirubin is critical for infant survival
and mental health
- can easily accumulate in the brain
since newborns’ brain barrier are still
underdeveloped
HYPERBILIRUBINEMIA (newborn) – Jaundice
 Hemolytic disease of the newborn
 Underdeveloped liver of premature
newborns
Microcollection tubes:
a. Amber-colored tubes
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PCML112 | PRINCIPLES OF MEDICAL TECHNOLOGY 2 (LECTURE)
Module 7: CAPILLARY PUNCTURE EQUIPMENT AND PROCEDURE

b. Covering tubes with carbon paper.
NEWBORN SCREENING
 part of routine check for infants to determine
inborn disorders such as phenylketonuria,
hypothyroidism, galactosemia, cystic
fibrosis.
 Testing of newborns for:
a. genetic
b. metabolic
c. hormonal, and
d. functional disorders
that may cause physical disabilities, mental
retardation, or even death, if not detected early (24
to 48 hours after birth)
 Presently, up to 50 inherited disorders can
be detected but only common disorders are
usually performed
 Blood is collected by heel prick and placed
on a special filter paper.
NBS should be done immediately after 24
hours of birth
Types of NBS in the Philippines
NBS
EXPANDED
NBS (ENBS)
Panels
6 disorders
≥ 28 disorders
Standardized
P550 to 600
P1750 to 1800
price
Philhealth
Until May 2019 May 2019 to
coverage
present
Availability
Hospitals, lying-in, rural health
units, health centers
Specimen
Medical Technologist, Physician,
Collector
Nurse, trained Midwife
 Parents who refuse to perform NBS on their
newborn must fill-up a Refusal form.
 Manner of reporting:
a. Negative screen - no disorder
b. Positive screen - must perform
confirmatory test on the panel.
NBS PANEL IN THE PHILIPPINES
 NBS - screening of 6 inherited disorders
DISORDER
DESCRIPTION COMPLICATI
ON
Phenylketonuria Lack of
Mental
enzyme that
retardation
metabolizes
(irreversible)
Congenital
Hypothyroidism
hormone
deficiency
Galactosemia
Lack of
enzyme that
converts
galactose to
glucose
Congenital
Adrenal
Hyperplasia
Lack of
enzymes
needed to
make specific

Importance:
 Newborn may appear normal at
birth
 Metabolic disorders may be detected
before clinical symptoms manifest.
 To start treatment immediately
NEWBORN SCREENING PROGRAM IN THE
PHILIPPINES
phenylalanine
Thyroid
adrenal
Delays in
growth and
brain
development
Mental
Retardation
Liver disease,
renal failure,
cataracts,
blindness,
mental
retardation,
death
Genital
ambiguity
Genital and
nipple
pigmentation
Hormones
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PCML112 | PRINCIPLES OF MEDICAL TECHNOLOGY 2 (LECTURE)
Module 7: CAPILLARY PUNCTURE EQUIPMENT AND PROCEDURE
G6PD deficiency
(Glucose-6phosphate
dehydrogenase)
Lack of
enzymes that
protect cells
from oxidative
Damage
MSUD (Maple
Syrup Urine
Disease)
Lack of
enzyme
needed to
breakdown
Leucine,
Isoleucine and
Exposure to
triggering
factors
may cause
hemolytic
anemia
Neurologic
damage
Valine
ENBS PANEL IN THE PHILIPPINES
 Expanded NBS (ENBS) - screening of more
than 28 inherited disorders
 Divided into 7 groups:
1. Endocrine disorders (2)
2. Amino acid disorders (5)
3. Fatty acids disorders (8)
4. Organic acid disorders (7)
5. Urea cycle defect (2)
6. Hemoglobinopathies (1 with 7 subtypes)
7. Others (4)
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