Clinical Decision Limits

Phoning limits for biochemistry tests are as follows:

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

 

Immunology results to be telephoned:

• 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)

Abnormal Laboratory Test Results – Triggers for Telephoning Results Haematology

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

Platelets	Clotting Studies
Lower limit - <70 x 10 9/L	INR - >5.0
Upper limit - >1000 x 10 9/L	PTT - >180 seconds
	Fibrinogen < 1.0g/l

• 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.

HPA Microbiology – List of abnormal results telephoned to clinical staff

Bacteriology

• 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

Virology

• 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