Table 3.

Experimental validation of cross-reactivity, including parent drugs and metabolites.a

Screening assayCompound testedParent drugConcentration causing a presumptive positive, μg/mL
Amphetaminesα-MethyldopamineMethyldopa13.6
Procainamide23.2
Ceftaroline fosamil53.1
N-acetyl-3-hydroxyprocainamideProcainamide92.2
Imatinib216.6
Esmolol237.3
Esmolol acidEsmolol446.4
MethyldopaNA
3-o-MethyldopaMethyldopaNA
DonepezilNA
6-o-DesmethyldonepezilDonepezilNA
BuprenorphineRotigotine0.13
Trimethoprim47.2
Procainamide92.8
N-acetyl-3-hydroxyprocainamideProcainamide126.2
Propafenone180.7
Ceftaroline fosamil681.5
Donepezil709.6
SulfamethoxazoleNA
CytarabineNA
CannabinoidsRaltegravir339.5
Rotigotine415.1
MethadonePropafenone83.2
Pazopanib198.4
  • a NA indicates the compound was not sufficiently cross-reactive to cause a presumptive positive on the given screening assay at the concentrations tested. Cytarabine was not expected to be cross-reactive. In addition, based on the EHR data analysis, the potential cross-reactivity of trimethoprim and sulfamethoxazole could not be distinguished.