Specimens from patients who have received glucarpidase (carboxypeptidase G2) as a high dose methotrexate rescue therapy should not be tested using this assay. These specimens have increased serum levels of 4-[[2,4-diamino-6- (pteridinyl)methyl]-methylamino]-benzoic acid (DAMPA)10-12 that result from metabolism of methotrexate by glucarpidase. DAMPA crossreacts with the methotrexate antibody used in this assay, and may continue to circulate for at least five to seven days before accurate measurements of serum methotrexate may return. Utilize a MISC order for Methotrexate, Post-Glucarpidase.
* This volume does not allow for repeat testing
Do not collect in a gel barrier tube (SST or PST)
Gel Barrier Tube
0.00 - 0.05 umol/L
Same day/next day
01420299
80299