Download Examination Paracetamol (Acetaminophen, N-Acetyl para

Examination
17744
Paracetamol (Acetaminophen, N-Acetyl para-amino
phenol)
Purpose of test
Investigation of suspected overdose
Sample
Blood
Sample Tube/Container
Adult- Yellow top or Green top Lithium Heparin Gel
Sample should be taken >4 hours after overdose.
An accurate sample time from ingestion is critical for
interpretation
Sample Volume
4ml
Minimum (see calculation of minimum volume)
Special Precautions
No specific requirements
Request Form:
Clinical Chemistry & Haematology Requests
Laboratory
Biochemistry
Biological reference range
Therapeutic level at 4 hours:
5 - 12 mg/L
Clinical decision values
See paracetamol poisoning guidelines in the medical
section of Trust clinical guidelines web page
Factors affecting performance In sample where icterus (bilirubin), haemolysis or lipemia
is indicated by the manufacturer to cause inaccuracy of
>10%, the result will be dashed out or reported with a
disclaimer
Plasma concentrations taken within 4 hours of ingestion
cannot be reliably interpreted because of the possibility of
continued drug absorption and distribution
Prone to interference from haemolysis
Amitriptyline and imipramine showed a significant negative
interference.
Inaccurate time from ingestion will adversely impact on
result interpretation
Turnaround times:
The Laboratory aims to report 90% of requests within the
stated time from receipt
Urgent - 1 hour
Ward - 4 hours
GP and OPD – 1 working day
Patient preparation
No specific requirements
Instructions for patient
collected sample
Not applicable
Note: Printed documents are not controlled
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Sample transportation
No specific requirements
Special handling needs
No specific requirements
Patient consent required
Implied consent
Specific rejection criteria
Generic rejection applies
Additional information
Part of overdose screen
Minimum Retest Intervals- not available
References
- Lab Tests Online
- Roche insert 2011-03, V 1 English
- WHO use of anticoagulants in diagnostic laboratory
investigations
- Trust guidance on management of paracetamol poisoning
- Commission human medicine Paracetamol overdose
guidance September 2012
- BNF 65 page 3
Note: Printed documents are not controlled
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