Reference Intervals for Laboratory Tests and Procedures

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Chapter 708 Reference Intervals for Laboratory Tests and Procedures

In Tables 708-1 through 708-6 (found on the Nelson Textbook of Pediatrics website at www.expertconsult.com ), the reference intervals apply to infants, children, and adolescents when possible. For many analyses, however, separate reference intervals for children and adolescents are not well delineated. When interpreting a test result, the reference interval supplied by the laboratory performing the test should always be used as these intervals are instrument and/or method dependent. See Figures 708-1 to 708-3 (also located on the Nelson Textbook of Pediatrics website at www.expertconsult.com ) for estimations related to dosages.

Table 708-1 PREFIXES DENOTING DECIMAL FACTORS

PREFIX	SYMBOL	FACTOR
Mega-	M	10⁶
Kilo-	k	10³
Hecto-	h	10²
Deka-	da	10¹
Deci-	d	10⁻¹
Centi-	c	10⁻²
Milli-	m	10⁻³
Micro-	µ	10⁻⁶
Nano-	n	10⁻⁹
Pico-	p	10⁻¹²
Femto-	f	10⁻¹⁵

Table 708-2 ABBREVIATIONS

Ab	Absorbance
AU	Arbitrary unit
BB	Brain isoenzyme of creatine kinase
cap	Capillary
CH₅₀	Dilution required to lyse 50% of indicator red blood cells; indicates complement activity
Cr	Creatinine
CSF	Cerebrospinal fluid
F	Female
g	Gram
hr	Hour, hours
Hb	Hemoglobin
HbCO	Carboxyhemoglobin
hpf	High-power field
IU	International unit of hormone activity
L	Liter
M	Male
MB	Heart isoenzyme of creatine kinase
mEq/L	Milliequivalents per liter
min	Minute, minutes
mm³	Cubic millimeter, microliter (µL)
mm Hg	Millimeters of mercury
mo	Month, months
mol	Mole
mmol	Millimole
mOsm	Milliosmole
MW	Relative molecular weight
ND	Not detected
nm	Nanometer (wavelength)
Pa	Pascal
pc	Postprandial
RBC	Red blood cell(s), erythrocyte(s)
RT	Room temperature
sec	Second, seconds
SD	Standard deviation
Tr	Trace
U	International unit of enzyme activity
V	Volume
WBC	White blood cell(s)
WHO	World Health Organization
wk	Week, weeks
yr	Year, years

Table 708-3 SYMBOLS

>	Greater than
≥	Greater than or equal to
<	Less than
≤	Less than or equal to
±	Plus or minus
≈	Approximately equal to

Table 708-4 ABBREVIATIONS FOR SPECIMENS

S	Serum
P	Plasma
(H)	Heparin
(LiH)	Lithium heparin
(E)	Ethylenediaminetetraacetic acid (EDTA)
(C)	Citrate
(O)	Oxalate
W	Whole blood
U	Urine
F	Feces
CSF	Cerebrospinal fluid
AF	Amniotic fluid
(NaC)	Sodium citrate
(NH₄H)	Ammonium heparinate

Table 708-5 KEY TO COMMENTS

30°C, 37°C	Temperature of enzymatic analysis (Celsius)
a	Values obtained are significantly method-dependent
b	Values in older males are higher than those in older females
c	Values in older females are higher than those in older males
d	Atomic absorption
e	Borate affinity chromatography
f	Cation-exchange chromatography
g	Vitros, a proprietary analytic system of Ortho Clinical Diagnostics, Inc.
i	Electrophoresis
j	Enzymatic assay
k	Enzyme-amplified immunoassay
l	Fluorometric method
m	Fluorescence-activated cell sorting (FACS)
n	Fluorescence polarization
o	Gas chromatography
p	High-performance liquid chromatography (HPLC)
q	Indirect fluorescence antibody (IFA) assay
r	Ion-selective electrode
s	Nephelometry
t	Optical density
u	Radial immunodiffusion (RID)
v	Radioimmunoassay (RIA)
w	Spectrophotometry

Table 708-6 REFERENCE INTERVALS*^†

Table 708-7 COMPOSITION OF COMMONLY USED ORAL AND PARENTERAL SOLUTIONS (RAYMOND ADELMAN AND MICHAEL SOLHAUG) [SEE RELATED CONVERSION TABLES 708-8 TO 708-10]

Table 708-8 METHOD FOR CONVERSION OF MILLIGRAMS TO MILLIEQUIVALENTS PER LITER (OR TO MILLIMOLES PER LITER)

Table 708-9 FACTORS OF CONVERSION OF CONCENTRATION EXPRESSED IN MILLIEQUIVALENTS PER LITER TO MILLIGRAMS PER DECILITER (100 L), AND VICE VERSA, FOR COMMON IONS THAT OCCUR IN PHYSIOLOGIC SOLUTIONS

Table 708-10 MILLIEQUIVALENTS AND MILLIGRAMS OF CATIONS AND ANIONS PRESENT IN 1 MILLIMOLE OF SALTS COMMONLY USED IN PHYSIOLOGIC SOLUTIONS

Table 708-11 FOOD COMPOSITION FOR SHORT METHOD OF DIETARY ANALYSIS (LEWIS A. BARNESS AND JOHN S. CURRAN)*

Table 708-12 NUTRITIVE VALUE OF BABY FOODS (PER SERVING)*

Table 708-13 EQUIVALENT TEMPERATURE READINGS (CELSIUS [C] AND FAHRENHEIT [F])*

Figure 708-1 Nomogram for the estimation of surface area. The surface area is indicated where a straight line that connects the height and weight levels intersects the surface area column, or if the patient is roughly of average size, from the weight alone (enclosed area).

(Nomogram modified from the data of E. Boyd by C.D. West. See also Briars GL, Bailey BJ: Surface area estimation: pocket calculator v nomogram, Arch Dis Child 70:246–247, 1994.)

Figure 708-2 Relationships among body weight (lb), body surface area, and adult dosage. The surface area values correspond with those set forth by Crawford JD, Terry ME, Rourke GM: Simplification of drug dosage calculation by application of the surface area principle, Pediatrics 5:783–790, 1950. Note that the 100% adult dose is for a patient weighing approximately 140 lb and having a surface area of approximately 1.7 m².

(From Talbot NB, Richie RH, Crawford JH: Metabolic homeostasis: a syllabus for those concerned with the care of patients, Cambridge, MA, 1959, Harvard University Press.)

Figure 708-3 Nomogram for risk assessement of hyperbilirubinemia.

(From Bhutani VK, Johnson L, Sivieri EM: Predictive ability of a predischarge hour-specific serum bilirubin for subsequent significant hyperbilirubinemia in healthy term and near-term newborns, Pediatrics 103:6−14, 1999, Fig 2, p 9.)