Skip to main content

Key messages

  • Normal pathology values are readily available for healthy term infants.
  • Consider laboratory error if spurious result are returned for a well baby.
  • Where possible, use local laboratory reference ranges.
  • Laboratory tests are only useful if they guide management.

Normal laboratory values are reference ranges used by clinicians to interpret results of laboratory tests.

In general, normal pathology values are readily available for healthy term infants. As (extreme) prematurity is a pathological condition in itself, be cautious when using the concept of ‘normal’.

In most cases, when considering the correction of ‘abnormal’ values, it is wise to consider the following:

  • Is this due to sampling or laboratory error?
  • Is the baby symptomatic?
  • What is the evidence that correcting the abnormality is beneficial?
  • Is there any risk or danger in correcting an abnormal result?

It is always advisable to keep in mind the reference ranges from your own laboratory as they will be analyser or population-specific. This is particularly important, for example, with respect to coagulation profiles. If your laboratory does not provide reference ranges for newborns or subsets thereof, the following may be helpful.

N.B. mm/L = micromol/litre.

Term infants (age of life)

Value
Cord
1-12 hr
12-24 hr
24-48 hr
48-72 hr
3-10 d
Na 
(mEq/L)
147
(126-166)
143 (124-156) 145 (132-159) 148 (134-160) 149 (139-162)  

(mEq/L)
7.8
(5.6-12)
6.4 (5.3-7.3) 6.3 (5.3-8.9) 6.0 (5.2-7.3) 5.9 (5.0-7.7)  
Cl 
(mEq/L)
103
(98-110)
101 (80-111) 103 (87-114) 102 (92-114) 103 (93-112)  
Ca (mmol/L) 2.33
(2.1-2.8)
2.1 (1.8-2.3) 1.95 (1.7-2.4) 2.0 (1.5-2.5) 1.98 (1.5-2.4)  
Ca (I) (mmol/L)   1.05-1.37 1.05-1.37 1.05-1.37 1.10-1.44 1.20-1.48
PO4 (mmol/L) 1.8
(1.2-2.6)
1.97 (1.1-2.8) 1.84 (0.9-2.6) 1.91 (1.0-2.8) 1.87 (0.9-2.5)  
Mg (mmol/L)     0.72-1.00   0.81-1.05 0.78-1.02
Urea (mmol/L) 10.4
(7.5-14.3)
9.6 (2.9-12.1) 11.8 (3.2-22.5) 11.4 (4.6-27.5) 11.1 (5.4-24.3)  
Creat (mmol/L)       0.04-0.11   0.01-0.09
CRP 
(mg/L)
<7 <7 <7 <7 <7 <7
Lactate (mmol/L) 1.5-4.5 0.9-2.7 0.8-1.2     0.5-1.4
Albumin (g/L) 28-43 28-43 28-43 28-43 28-43 30-43
ALP
(IU/L)
28-300 28-300 28-300 28-300 28-300 28-300
T4 8.2
(+/-1.8)
  19.0 (+/-2.1) 19.0 (+/-2.1) 19.0 (+/-2.1) 15.9 (+/-3.0)
TSH     3.0-120 3.0-30   0.3-10
Cortisol (nano
mol/L)
200-700 200-700 200-700      
17-OHP (nano
mol/L)
        0.7-12.4 0.7-12.4
Hb (g/L) 168   184   178 170
Hct (%) 53   58   55 54
MCV 107   108   99 98
Retic (%) 3-7   3-7   1-3 0-1
WCC x 109/L 18.1 (9-30) 22.8 (13-38) 18.9 (9.4-34)     12.2 (5-21)
Neutro x 109/L 11.1 (6-26) 15.5 (6-28) 11.5 (5-21)     5.5 (1.5-10)
Lymph x 109/L 5.5 (2-11) 5.5 (2-11) 5.8 (2-11.5)     5.0 (2-17)
Mono x 109/L 1.1 1.2 1.1     1.1
Eosin x 109/L 0.4 0.5 0.5     0.5
Platelets (103/mm3 ) 150-350 150-350 150-350 150-350 150-350 150-350
PT (sec)   11-14 11-14 11-14 11-14 11-14
APTT (sec)   23-35 23-35 23-35 23-35 23-35
FBG (mg/dL)   200-400 200-400 200-400 200-400 200-400
Capillary refill   < 3 seconds < 3 seconds < 3 seconds < 3 seconds < 3 seconds

 

Acid base values* - term and preterm infants (by age of life)

Value
Cord
1-12 hr
12-24 hr
24-48 hr
Range**
pH 7.33 (UV) 7.30 (art) 7.30 (art) 7.39 7.25-7.45
PCO2 (mmHg) 43 (UV) 39 33 34 35-50
HCO3 (mEq/L) 21.6 (UV) 18.8 19.5 20 17-28
PO2 (mmHg) 28 (+/-8) (UV) 62 (+/-13.8) 68 63-87 60-80
Anion gap <20 <20 <20 <20 8-16

* Capillary ranges similar except pO2
** Very difficult to define, wide variation within/between level III units

Electrolytes - preterm infants (< 37 weeks) (by day of life)

Value
Day 1
Day 3
Day 7
Day 21
Day 35
Day 49
Na (mEq/L) 140 (133-146) 140 (133-146) 140 (133-146) 136 (129-142) 137 (133-148) 137 (133-142)
K (mEq/L) 5.6 (4.6-6.7) 5.6 (4.6-6.7) 5.6 (4.6-6.7) 5.8 (4.5-7.1) 5.5 (4.5-6.6) 5.7 (4.6-7.1)
Cl (mEq/L) 108 (100-117) 108 (100-117) 108 (100-117) 108 (102-116) 107 (100-115) 107 (101-115)
Ca (millimol/L) 2.3 (1.5-2.9) 2.3 (1.5-2.9) 2.3 (1.5-2.9) 2.4 (2.0-2.8) 2.4 (2.2-2.6) 2.4 (2.2-2.7)
Ca (I) (millimol/L) 0.81-1.41 0.72-1.44 1.04-1.52 (d5) 1.04-1.52 1.04-1.52 1.04-1.52
PO4 (millimol/L) 2.5 (1.7-3.5) 2.5 (1.7-3.5) 2.5 (1.7-3.5) 2.4 (2.0-2.8) 2.3 (1.8-2.6) 2.2 (1.4-2.7)
Mg (millimol/L) 0.62-1.02 0.66-1.10 0.75-1.00 0.75-1.00 0.75-1.00 0.75-1.00
Urea (millimol/L) 3.3 (1.1-9.1) 3.3 (1.1-9.1) 3.3 (1.1-9.1) 4.8 (0.8-11.2) 4.8 (0.7-9.5) 4.8 (0.9-10.9)

Other biochemistry - preterm infants (by gestation)

Value
27 weeks
29 weeks
31 weeks
33 weeks
35 weeks
Alb (g/L) 21-33 23-34 22-35 22-35 22-36
ALP (IU/L) 35-604 119-465 112-450 110-398 113-360
Creat (micromol/L) day 2 0.08-0.16 0.07-0.14 0.07-0.14 0.05-0.13 0.05-0.13
Creat (micromol/L) day 7 0.05 -0.11 0.04-0.12 0.04-0.12 0.02-0.11 0.02-0.11
Creat (micromol/L) day 14 0.04-0.10 0.04-0.10 0.04-0.10 0.02-0.09 0.02-0.09
Creat (micromol/L) day 21 0.03-0.09 0.03-0.09 0.03-0.09 0.02-0.09 0.02-0.09
Creat (micromol/L) day 28 0.03-0.08 0.02-0.09 0.02-0.09 0.01-0.06 0.01-0.06

Haematology - preterm infants (by age)

Value
Birth
12 hours
24 hours
1 week
2 weeks
1 month
Hb (g/L) 140 (24 wks)          
  145 (28 wks)          
  150 (34 wks)          
WCC x 109/L 18.1 (9-30) 22.8 (13--38) 18.9 (9.4-34) 12.2 (5-21) 11.4 (5-20) 10.8 (5-19.5)
Neutro x 109/L 11.1 (6-26) 15.5 (6-28) 11.5 (5-21) 5.5 (1.5-10) 4.5 (1-9.5) 3.8 (1-9)
Lymph x 109/L 5.5 (2-11) 5.5 (2-11) 5.8 (2-11.5) 5 (2-17) 5.5 (2-17) 6.0 (2.5-16.5)
Mono x 109/L 1.1 1.2 1.1 1.1 1.0 0.7
Eosin x 109/L 0.4 0.5 0.5 0.5 0.4 0.3
Platelets (103/mm3 ) 150-350 150-350 150-350 150-350 150-350 150-350

Coagulation profile - preterm infants (by age)

Value
Day 1
Day 5
Day 30
PT (sec) 13 (10.6-16.2) 12.5 (10-15.3) 11.8 (10-13.6)
APTT (sec) 53.6 (27-79) 50.5 (27-74) 44.7 (27-62)
FBG (g/L) 2.43 (1.5-3.7) 2.8 (1.6-4.2) 2.54 (1.5-4.14)

CSF - term and preterm infants (by age of life)

Value
Term < 7d
Term > 7d
Preterm < 7d
Preterm > 7d
WCC (mm3) 5 (0-30) 3 (0-10) 9 (0-30) 12 (2-70)
RCC (mm3) 9 (0-50) <10 30 (0-333) 30
Protein (g/L) 0.6 (0.3-2.5) 0.5 (0.2-0.8) 1 (0.5-2.9) 0.9 (0.5-2.6)
Glucose (millimol/L) 3 (1.5-5.5) 3 (1.5-5.5) 3 (1.5-5.5) 3 (1.5-5.5)

Urine - term and preterm infants

Value
Term < 7d
Term > 7d
Preterm < 7d
Preterm > 7d
WCC (per HPF) <5 <5 <5 <5
RCC (per HPF) 0-2 0-2 0-2 0-2
Squames (per HPF) <5 <5 <5 <5
Organisms Nil Nil Nil Nil

More information

References

  • Rennie JM, Roberton NRC (Eds). Textbook of Neonatology, 3rd edn. Churchill Livingstone, Edinburgh, 1999.
  • Taeusch HW, Ballard RA (Eds). Averys Diseases of the Newborn 7th edn. W.B. Saunders Company, Philadelphia. 1998

Other reading

  • Forfar JO. Normal and abnormal calcium, phosphorus and magnesium metabolism in the perinatal period. Clinics in Endocrinol and Metab 1976;5:123-48
  • Kuhne T, Imbach P. Neonatal platelet physiology and pathophysiology. Eur J Pediatr 1998;157:87-94
  • Hajjar FM. Neutrophils in the newborn: Normal characteristics and quantitative disorders. Sem Perinatol 1990;14:374-83
  • Strozik KS, Pieper CH, Roller J. Capillary filling time in newborn babies: normal values. Arch Dis Child 1997;76:F193-6
  • Buchanan G. Neonatal coagulation: Normal physiology and pathophysiology. Clin Haematol 1978;7:85-109

Get in touch

Maternity and Newborn Clinical Network
Safer Care Victoria

Version history

First published: September 2013

Last reviewed: October 2018

Review by: TBC

UNCONTROLLED WHEN DOWNLOADED

Page last updated: 23 Nov 2018

Was this content helpful to you?