Critical Test Results and Laboratory Values

The following lists the laboratory tests with critical test results. Critical test results are informed by telephone to the requesting physician and the communication recorded in the laboratory test report and in the laboratory information system.

Clinical Biochemistry

Test	Values	Units
Potassium	< 2.5 or > 5.7	mmol/L
Sodium	< 120 or > 160	mmol/L
Calcium	< 1.75 or > 3.25	mmol/L
Glucose	< 2.5 or > 25.0	mmol/L
pH (blood gas)	< 7.1 or > 7.6
Calcium, ionised	< 0.80 or > 1.60	mmol/L
Digoxin	> 2.4	µg/L
Theophylline	> 20	mg/L
Paracetamol	Inform all results	mg/L
Salicylate	Inform all results	mmol/L
Ketone, blood	> 1.4	mmol/L
Lithium	> 2.0	mmol/L
Bilirubin (neonates only)	> 299	µmol/L
Amikacin	> 35	mg/L
Gentamicin	> 15	mg/L
Phenobarbital	> 40	mg/L
Phenytoin	> 20	mg/L
Valproic acid	> 100	mg/L
Vancomycin	> 80	mg/L

Haematology

Test	Values	Units
APTT	> 100	seconds
INR	> 5.0
Haemoglobin (for Adult)	< 6.0 or > 20.0	g/dL
Haemoglobin (Newborn)	< 6.0 or > 25.0	g/dL
WBC	< 1.0 or > 50.0 x 10⁹	/L
Platelets	< 20 or > 800 x 10⁹	/L
Malarial Parasites	Positive
Fibrinogen	< 0.9 or > 7.8	g/L
New cases of leukaemia
Combination of strong positives (++) for glucose and ketones when dipstick is ordered

Microbiology

First time AFB smear positive specimens
Microscopic examination of positive blood culture broths
VZV IgM, VZV antigen positive in pregnant women at term, newborns, immunocompromised patients, infected Healthcare Worker (HCW) / patients in contact with immunocompromised patients/newborns, adults with pneumonia
HSV antigen, HSV IgM positive in viral encephalitis, newborns, pregnant women in labour, immunocompromised patients
Antibody positive to any neurotropic virus – when a titer is ≥ 8 in a CSF sample
Sars-CoV IgM/ Sars-CoV isolation/ MERS-CoV isolation/ Influenza A (H5) in any new case

Molecular

All positive results for cerebrospinal fluid
Positive result for SARS Coronavirus PCR
Positive result for Avian influenza H5N1 PCR or H7N9 PCR
Positive result for MERS coronavirus PCR