Sign in →

Test Code MTX Methotrexate Level, Blood

Important Note


Clinical System Name

Methotrexate Level Bld

Sample Requirements

Specimen: Whole blood

Container(s):  Gold SST, Lt. Green/Lithium Heparin, Dark Green/Sodium Heparin

Preferred Vol: 1.0 mL

Minimum Vol: 0.5 mL


Note:   Protect sample from light.  In-patients:  wrap paper towel around tube and seal with one piece of tape.  Off-site:  wrap tube in foil.  Specimen stable under fluorescent lighting for up to 4 hours.  


Note time and date of drug administration, and blood collection.  Draw times are determined by the treatment protocol; call Chemistry (206) 987-2565 for assistance in determining draw times.



Processing Instructions

Between 08:00 to 16:00 (M-F)

Reject due to: prolonged light/UV exposure

Spin: N

Aliquot: N

Temp: RT

Storage location:  Tube community service and unspun samples with labels to 10th floor.  




Between 16:00 to 08:00 (and weekends all hours)

Reject due to: prolonged light/UV exposure

Spin: Y

Aliquot: Y

Temp: 2-8 C

Storage location:  Spin and refrigerate Gold SST in CPA refrigerator, FrigA rack. Aliquot non-SST serum/plasma.


Off-site collection: Protect sample from light by wrapping tube in foil.  Note time of collection.  Send aliquotted serum/plasma frozen.


Specimen Type Temperature Time
serum RT

≤ 4 H


1 w


1 y



STAT Performed TAT
N Daily 1 d


Specimens received by 10:00 are reported by 12:00.  Specimens received by 12:00 are reported same day.

Performing Laboratory

Seattle Children's Laboratory    


Department:  Chemistry

Location: Chem West

Phone Number: 206-987-2617



Reference Range

Contact Chemistry (206) 987-2565 for expected levels.


Method: Enzyme immunoassay by Vitros 4600

Analytical Volume:  0.150 mL serum

CPT Codes