Laboratory Medicine

Test catalogue

Methotrexate
Test Name Methotrexate
Specimen Type/Requirements Container Type = 1 Red Top Minimum Testing Volume = 0.5 mL blood Tubes must fill to at least ½ or greater of its vacuum capacity
Specimen Handling Collection Instructions: Collect sample in red top vacutainer. Ensure both sample and requisition are labelled properly. Protect specimen from light. Specimen must be labelled inside and outside light-protecting wrap. Plasma collected with heparin, EDTA or oxalate as an anticoagulant is acceptable. The sampling time of methotrexate is dependent on dose, duration of infusion and clinical status of the patient. The time of sample collection and the last dose must be recorded. Laboratory Staff Instructions: Serum should be separated from cells within 2 hours of collection. Rejection Criteria: Sample not protected from light, gel separator tube, unlabeled or samples of non sufficient quantity. Stability: Stable at room temperature for 3 days, refrigerated for 14 days, and frozen for 28 days. Transportation: Send to Core Lab as soon as possible.
Required Documentation
Turnaround Time (TAT) STAT: 45 minutes Routine: 2 hours	Test Utilization N/A
Reference Value Critical Values - Toxic Concentrations: 24h after high dose: >10.00 umol/L 48h after high dose: >1.00 umol/L 72h after high dose: >0.10 umol/L All results > 5.00 umol/L will be called, all results < 5.00 umol/L will not be called.
Test Code MTX	Methodology Competitive Binding Immunoenzymatic Assay
Testing Location SMH-Biochemistry	Other Information Last Updated: June 22, 2026

Methotrexate

Test Name

Methotrexate

Specimen Type/Requirements

Container Type = 1 Red Top

Minimum Testing Volume = 0.5 mL blood

Tubes must fill to at least ½ or greater of its vacuum capacity

Specimen Handling

Collection Instructions: Collect sample in red top vacutainer. Ensure both sample and requisition are labelled properly. Protect specimen from light. Specimen must be labelled inside and outside light-protecting wrap. Plasma collected with heparin, EDTA or oxalate as an anticoagulant is acceptable. The sampling time of methotrexate is dependent on dose, duration of infusion and clinical status of the patient. The time of sample collection and the last dose must be recorded.

Laboratory Staff Instructions: Serum should be separated from cells within 2 hours of collection.

Rejection Criteria: Sample not protected from light, gel separator tube, unlabeled or samples of non sufficient quantity.

Stability: Stable at room temperature for 3 days, refrigerated for 14 days, and frozen for 28 days.

Transportation: Send to Core Lab as soon as possible.

Required Documentation

Turnaround Time (TAT)

STAT: 45 minutes

Routine: 2 hours

Test Utilization

N/A

Reference Value

Critical Values - Toxic Concentrations:

24h after high dose: >10.00 umol/L

48h after high dose: >1.00 umol/L

72h after high dose: >0.10 umol/L

All results > 5.00 umol/L will be called, all results < 5.00 umol/L will not be called.

Test Code

MTX

Methodology

Competitive Binding Immunoenzymatic Assay

Testing Location

SMH-Biochemistry

Other Information

Last Updated: June 22, 2026