DIFFERENCES OF LABORATORY
INVESTIGATIONS IN PEDIATRICS
Hana Vinohradská, M.D.
Department of Clinical Biochemistry
University Hospital Brno
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Children
• aren´t small adults
• are unique group with many differences
• their organs, systems and functions gradually mature
after the birth
• the important physiological and maturational
changes occur in their development, especially
during early childhood and then during puberty
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Anatomical and functional traits
• a bigger body surface to body weight
• more water and less fat in their bodies
• less protective muscles around their organs
• smaller airways
• higher metabolic rate
• lower blood pressure, faster heart rate
• less mature immune system etc.
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Metabolic differences in newborns
• These differences reflect the trauma of birth and
postnatal adaptation of newborn to an independent
existence
• Arterial blood oxygen saturation is very low initially
• Metabolic acidosis is developed
• Plasma proteins increase in blood
• Serum activities of several enzymes such GGT, CK and
AST are higher
• Concentration of bilirubin increases after birth and peaks
around the third to fifth day of life, usually doesn‘t
exceed 85 umol/l
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Metabolic differences
in newborns and in infants
• Blood glucose concentration is low in newborns
• Clearence of creatinine is low, especially in preterms
neonates
• Potassium concentration – may be as high as
7 mmol/l after birth, but then it rapidly falls
• Calcium concentration – is also high inicially, it decreases
during the first day
• Serum IgG - concentration decreases during the first
three month, later gradually increases
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Metabolic differences at puberty
• Serum alkaline phosphatase activity rises with skeletal
growth
• Rising concentrations of sex hormones due to sexual
maturation
• Serum creatinine concentration increases from infancy
to puberty parallel to development of skeletal muscle,
especially in boys
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Specimen collection and processing
• Collection of biological material in childhood has its own
specificities
• Blood collection - traumatic, invasive procedure
• 3 techniques: capillary blood, syringe-needle
technique, evacuated blood tube
• In small children blood may be obtained by skin
puncturing
• In neonates and infants - heel skin puncture, in older
children - finger prick
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Sample collection by skin puncturing
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Collection on filter paper
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Sample tube
volume 7,5 ml
Sample tube
volume 1,2 ml
Sample tube
volume 0,6 ml
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Recommended maximum
volume of drained blood
for children
(University Hospital Motol)
Patient
weight
(kg)
Maximum
for one
collection
(ml)
Maximum
for month
(ml)
0,5-0,9 1 8
0,9-1,8 1,5 12
1,8-3,0 2 17
3-4 2,5 23
4-5 3,5 30
5-7 5 40
7-9 10 60
9-11 10 70
11-14 10 80
14-16 10 100
16-18 10 130
18-21 20 140
21-23 20 160
23-25 20 180
25-27 20 200
27-30 25 220
30-32 30 240
32-34 30 250
34-36 30 270
36-39 30 290
39-41 30 310
41-43 30 330
43-46 30 350
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Collection of urine from children
Plastic bag for collection of urine
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Differences in processing of biological
material of children
• Prevent sample evaporation, it is very important for
small volumes of samples, especially in summer
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Evaporation of serum sample (0,1 ml)
at laboratory temperature
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Differences in processing of biological
material of children
• Prevent sample evaporation, it is very important for
small volumes of samples, especially in summer
• Use appropriate analytical systems in laboratories ,
which require low volume of the sample.
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tube
„pediatric cup“
„microcup“
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Differences in processing of biological
material of children
• Prevent sample evaporation, it is very important for
small volumes of samples, especially in summer
• Use appropriate analytical systems in laboratories ,
which require low dead volume of the sample.
• The use of POCT devices
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65µl blood, 35 sec., 17 (19) parameters
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• ABR (pH, pO2, pCO2, saturation
Hb)
• Ions (Na, K, Cl, Ca++)
• Hb (totalHb, MetHb, COHb,
OxyHb, …)
• Bil
• Glu, Lact
• Urea, creatinine ??
POCT ABR
Pediatric reference ranges
• Using of corresponding reference values for
children is necessary
• Establishing age-specific reference ranges is
difficult process
• Results of laboratory test within or without
reference ranges ≠ definitive indicators of health
or ill
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Reference ranges of Creatinine (S/P)
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age (up to)
reference range [mmol/l]
from to
children
1 month 27,0 77,0
1 year 14,0 34,0
3 years 15,0 31,0
5 years 23,0 37,0
7 years 25,0 42,0
9 years 30,0 47,0
11 years 29,0 56,0
13 years 39,0 60,0
15 years 40,0 68,0
M 59,0 104,0
F 45,0 84,0
Pediatric reference ranges
• Steven J.Soldin: „Pediatric reference intervals“
(7th edition, 2011, 250 chemistry and hematology
analytes)
• www.ifcc.org (International Federation of Clinical
Chemistry and Laboratory Medicine)
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Children aren´t small adults! 22