Methotrexate
Ordering Info & Methodology
Test Code
Cerner Synonyms
MTXB
Methotrexate, mtx, TDM
Turn Around Time
Methodology
Ordering Guide
Obtain last dose information. Test code includes dosage, time and date of last dose.
Specimen Requirements
Sample Type
Collection Container
Alternate Collection Containers
Serum
Red
Dark Green (NO gel)
1.0 mL
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
Remove serum or plasma from cells within 1 hour of collection. Specimens must be sent same day as collection. If the afternoon BCCH courier is missed, batch samples and send by cab prior to the end of shift (1500 or 2300), 7 days a week.
Reference Intervals
Female Reference Interval
Age Category | Reference Interval | units |
|---|---|---|
Male Reference Interval
Age Category | Reference Interval | units |
|---|---|---|
Additional Notes
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.
Measurement Uncertainty