Acetaminophen
Ordering Info & Methodology
Test Code
Cerner Synonyms
APHN
Acetaminophen, Tylenol, Paracetamol, Anacin 3, Datril, Excedrin, Phenacetin
Turn Around Time
Methodology
Analyzed within 4 hours of receipt, 24/7. Available on a STAT basis.
Enzymatic Colorimetric, Roche cobas c
Ordering Guide
APHN
Specimen Requirements
Sample Type
Collection Container
Alternate Collection Containers
Lithium Heparin Plasma
Light Green
Gold, Red
0.5 mL
Seven days
Add on stability
This is the length of time after sample collection that this analyte is stable. Test can be added to a previously collected sample if the time since collection is less than the add on stability time.
Minimum Volume
Add On Stability
Collection and Shipping Requirements
Refrigerate. Send on ice pack.
Reference Intervals
Female Reference Interval
Age Category | Reference Interval | units |
|---|---|---|
≥ 0 y | <66 | umol/L |
Male Reference Interval
Age Category | Reference Interval | units |
|---|---|---|
≥ 0 y | <100 | ug/mL |
Additional Notes
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Measurement Uncertainty (MU)
Every laboratory value is an estimate of the true concentration of substance. MU is the 95% confidence interval around that estimate. 95% of the time, the true concentration will be within the range of the reported value ±MU. This value is based on analytical variability (precision) and does not reflect other factors such as sample collection and handling which may also affect the result.
Example
Reported sodium = 140 mmol/L
Sodium MU = 1%
Expanded uncertainty = 140 mmol/L ± 1% or 140mmol/L ± 1.4 mmol/L
Interpretation - the true value of sodium in the sample is in the range 138.6-141.4 mmol/L, with 95% confidence.
3%
Measurement Uncertainty
This assay is known to have a negative interference from N-acetyl cysteine (NAC). This means that in patients receiving NAC, the actual acetaminophen concentration may be higher than reported.
Accordingly, in the setting of overdose and NAC therapy, acetaminophen will be reported by St. Paul's Hospital until the concentration goes below the limit of detection (66 umol/L), after which time the specimens will be referred to the BC Childrens and Womens Hospital which uses an assay unaffected by NAC.
NAC administration should continue until the acetaminophen as reported by BC Childrens and Womens Hospital becomes undetectable.