Blood Testing Schedule on the Neonatal Unit

Publication: 21/01/2014  --
Last review: 14/02/2020  
Next review: 06/02/2022  
Standard Operating Procedure
ID: 3646 
Approved By: Trust Clinical Guidelines Group 
Copyright© Leeds Teaching Hospitals NHS Trust 2020  


This Standard Operating Procedure is intended for use by healthcare professionals within Leeds unless otherwise stated.
For healthcare professionals in other trusts, please ensure that you consult relevant local and national guidance.

Schedule of Routine Laboratory Blood Tests on NNU

The healthcare requirements of pre-term and sick term babies differ significantly from those of adults and older children.  Laboratory investigations are regularly clinically indicated more frequently than the pathology suggested re-testing guidelines.

It is recognised that repeated blood sampling of these vulnerable patients results in deleterious outcomes in terms of both iatrogenic anaemia and handling induced clinical instability. It is our practise to minimize the handling experienced by our patients by clustering investigations so as to reduce both the frequency of venepuncture and the blood volumes required.

Below is the neonatal units’ routine testing regime.  Babies who are acutely unwell may require more frequent investigations, this will be decided on an individual basis by the attending consultant. The attending consultant will specify if the baby is critically unstable, unstable




Admission to NNU

Group and Coombs
Blood culture

At admission



12-24 hours of age

Critically unstable baby
e.g. <28 weeks in first 48 hrs,

U+E, bilirubin
LFT, Ca, PO4, Mg, CRP, FBC

12 hourly

Severe jaundice


4-6 hourly*

Acutely deranged electrolytes


6-8 hourly

Unstable baby
e.g. unstable PN script or
clinically unstable baby

U+E, bilirubin, FBC, CRP
Ca, PO4, Mg, LFT

As per PN, (D/W Pharmacy)

Stable Baby on PN
e.g stable baby with stable PN script

Ca, PO4, Mg, LFT

Twice weekly
Weekly (Friday am)

Stable baby on enteral supplements

U+E, LFT, Ca, PO4, Mg
FBC  (+retics if Hb < 100)


Stable baby not on supplements

No routine testing


Responsible pathology re-testing guidelines

Full Blood Count (FBC)

12 Hours 

 Urea and Electrolytes (U+E)

12 Hours 

 C Reactive Protein (CRP)

24 Hours 

 Liver Function Test (LFT)

1.5 Days 

 Calcium Profile / Phosphate (Ca / PO4)

1.5 Days 

 Magnesium (Mg)

1.5 Days 

Lipids  (TG)        

28 Days 

Other Abbreviations used:
HIE;  Hypoxic Ischaemic Encephalopathy
MAS: Meconium Aspiration Syndrome
PN:  Parenteral Nutrition

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Record: 3646
Clinical condition:
Target patient group: Neonates
Target professional group(s): Secondary Care Doctors
Secondary Care Nurses
Adapted from:

Evidence base

Not supplied

Approved By

Trust Clinical Guidelines Group

Document history

LHP version 2.0

Related information

Not supplied

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