Methotrexate

Test Code

648

CPT Codes
80204

Preferred Specimen

1 mL frozen serum collected in a red-top tube (no gel) - protected from light

Patient Preparation
Collect 24, 48, or 72 hours after dose

Minimum Volume

0.2 mL

Other Acceptable Specimens

Frozen plasma collected in an: EDTA (lavender-top), fluoride oxalate (gray-top tube), sodium or lithium heparin (green-top) tubes - protected from light

Instructions

Protect sample from light. Record hours from last dose on specimen container and in remark column on the test requisition.

Transport Temperature

Frozen

Specimen Stability

Room temperature: 24 hours
Refrigerated: Unacceptable
Frozen: 5 days

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)

Serum separator tubes SST® or any other tube with additives • Thawed samples

Methodology
Immunoassay (IA)

Setup Schedule

Set up: Mon-Sat; Report available: Next day

Reference Range

<5.00 umol/L at 24 hours

<0.50 umol/L at 48 hours

<0.20 umol/L at 72 hours

For conventional low dose leucovorin rescue.

Clinical Significance

Methotrexate is an antimetabolite used in the treatment of certain neoplastic diseases, psoriasis and rheumatoid arthritis. In combination with other chemotherapeutic agents, high dose methotrexate doses followed by leucovorin rescue may be effective in prolonging relapse-free survival in patients with non-metastatic osteosarcoma. Methotrexate levels are monitored to assess toxicity.

Performing Laboratory
Quest Diagnostics Nichols Institute
14225 Newbrook Drive
Chantilly, VA 20153

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.