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Please note that all guidance is currently under review and some may be out of date. We recommend that you also refer to more contemporaneous evidence in the interim.
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) | |
| K (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
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Version history
First published: September 2013
Last reviewed: October 2018
Review by: TBC
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Page last updated: 02 Feb 2023