Laboratory Test Reference Guide

Laboratory Information

Test Name

Methotrexate

External Price (excl. GST)

46.63

Specimen Collection

Adult Specimen

Plain Red top tube ONLY. Do not use gel tubes for this assay.

Pre Testing Requirements

N/A

Instructions for Referral to Waikato Lab

Aliquot Transport

Frozen

Test Information

Department

Biochemistry

Test Availability

Mon - Sun, 24hrs

Laboratory Turnaround Time

3 hours

Method

Cobas Pro ARK

Unit of measurement

umol/L

Reference interval

 It is vital to correlate the measured level with the specific methotrexate protocol being used

 Major toxicities that can result from high plasma/serum levels include myelosuppression, mucosistis and nephrotoxicity. 

Mucositis and bone marrow suppression are directly influenced by the dose of Methotrexate given
and the length of time it remains in the blood.
As a guide, clearance is defined as adequate with plasma/serum concentrations of:
 <10     umol/L at 24 hrs
 <0.5    umol/L at 48 hrs
 < 0.05 umol/L at 72 hrs.

Uncertainty of measurement

20%

Minimum Volume

0.2 mL plasma or serum.

Electronic Information

Registration Code

METX

HL7 mapping code

$METX