Clinical Decision Limits

Written by Craig Webster on 09 May 2014.

Decision limits for phoning

Analyte	Phone results below or equal to:	Phone results above or equal to:	Units	Notes
Sodium	120	150	mmol/L
Potassium	2.5	6.5	mmol/L
Urea	-	Adults: 30 Paediatrics: 10	mmol/L	Except those on renal wards or under renal consultants.
Creatinine	-	Paediatrics: 200	umol/L
eGFR	Adults: 15	-	ml/min
AKI	-	2		Not CKD patients (AKI 2 discretionary)
Glucose	2.5	25	mmol/L
Calcium adjusted	1.8	3.5	mmol/L
Magnesium	0.4	-	mmol/L
Phosphate	0.3	-	mmol/L
AST	-	600	U/L
ALT	-	600	U/L
Total CK	-	5000	U/L
Amylase	-	500	U/L
Digoxin	-	2.5	ng/mL
Theophylline	-	25	mg/L
Phenytoin	-	25	mg/L
Lithium	-	1.5	mmol/L
Troponin T	-	GP only: >14	ng/L	GP only
Ammonia	-	100	umol/L
Ethanol	-	Paediatrics only: any detectable	mg/L	Paediatrics only
Paracetamol	-	10	mg/L	Not ED patients
Salicylate	-	300	mg/L	Not ED patients
Conj bilirubin (DBIL)	-	Paediatrics only: 25	umol/L	Paediatrics only
Total bilirubin	-	Paediatrics only: 225	umol/L	Paediatrics only
Carbamazepine	-	25	ug /mL
Iron	-	ED only: 70	umol/L	ED only
Phenobarbitone	-	70	mg/L
CSF Gluc	3.3	-	mmol/L
CSF Prot	-	0.45	g/L
Lactate	-	2.3
CRP	-	300
Total bile acids	-	20
Methotrexate	Phone all		umol/L

CD4 count <200 cells/cumm or <10% on new patients (paediatric levels are different, but agreed with Paed consultants)
Lymphocyte subsets in infants <2yo: Any T cell subset below age-related normal range, any other abnormality suggesting SCID (e.g. MHC class II deficiency). (Note this is not exclusive: any abnormality may be discussed with requesting clinician)
New positive GBM antibodiest
New positive MPO antibodies
New positive PR3 antibodies
New paraprotein IgG , A or M > 20g/L
- IgD or IgE (any size)
- serum monoclonal free light chains (any size, whether or not with intact paraprotein)

Haemoglobin	White Blood Cell Count
<8.0 g/dl normochromic and normocytic	Low result – neutropenia <0.5 x 10 9/L
<7.0 g/dl microcytic and hypochromic	High result – White cell count >40 x 10 9/L
<7.0 g/dl macrocytic	or Lymph count > 20 x 10 9/L
<5.0 g/dl renal patients	Any presence of blast cells

All Positive Malaria Screens
All Anti FXa results >1.20 iu/ml
If the patient is known to the department and has had a similar result within the previous 7 days then the urgent contact is not necessary.

Gram stain results of positive blood culture on Day 1
Positive CSF results
Positive sterile site results
Significant in-patient results from enteric bench
Multi resistant gram negative and gram positive isolates including mupirocin resistant MRSA
Group B streptococcal isolates from neonates
Group A in patient isolates
Positive Legionella urinary antigen and Pneumococcal urine antigen results
Smear and culture positive Mycobacteria
Antibiotic assay results outside normal ranges
Any other significant results at the discretion of Medical Microbiologists

Serological evidence of acute infection with Hep A, Hep B and in pregnant patients CMV, Parvovirus and Rubella
New diagnoses of HIV
VZV IgG negative from exposed patients at risk of severe VZV infection
New diagnosis of Hep B, Hep C and HIV in haemodialysis patients
Evidence of Hep B/Hep C and HIV in needle stick injury source patients
Clinically important positive respiratory PCR results i.e.: influenza, RSV in immunocompromised patients
Positive PCR results in outbreaks
Positive blood PCR for CMV and Adenovirus
Negative blood results for CMV PCR
Significant blood PCR results for EBV and Polyomavirus
All positive PCR results on CSF specimens
All positive Chlamydia PCR results on eye swabs
All positive PCR results from neonatal unit