SKC 560-002 MethChek Immunoassay Wipe Kit - Manual (Page 8)

8
Interferences
The MethChek Step 3 Cartridge is designed to react positively to
methamphetamine above the particular kit’s lower limit of identifi cation.
Possible Positive Interferences
Negative Interferences
There are no known negative interferences.
Possible Causes for Invalid Tests
Invalid test results are a rare occurrence. Possible causes for an invalid result can
include: damaged test cartridge, storage at high temperatures, expired test cartridges,
interferences in the sample (strong organics, bleaching agents, extremely high or
low pH), or improper test procedure (cartridge not held fl at during development,
insuffi
cient sample volume). If an invalid test result appears, perform a new test
with a new cartridge.
If no lines appear on the Step 3 Cartridge, it may be due to one of the following:
insuffi
cient volume of extract liquid was added to the Step 3 Cartridge or extract
liquid was added to the sample window instead of the sample well (marked “S”)
on the Step 3 Cartridge.
Compound
Approx. ng Equivalent to
50 ng/ml d-methamphetamine % Cross-reactivity
MDMA (Ecstasy) < 50 +100
d-methamphetamine 50 100
street methamphetamine
(methamphetamine hydrochloride, unknown purity) 50 100
d,l-methamphetamine 80 62
l-methamphetamine 650 8
d-amphetamine 2500 2
phenylephrine (component of nasal sprays) 2500 2
d-ephedrine 4000 0.3
l-ephedrine > 5000 < 1.0
d,l-ephedrine > 5000 < 1.0
d-phenylpropanolamine > 5000 < 1.0
d,l-phenylpropanolamine > 5000 < 1.0
d-pseudoephedrine > 5000 < 1.0
l-pseudoephedrine > 5000 < 1.0
heroin > 1,000,000 < 0.005
powder cocaine > 1,000,000 < 0.005
street cocaine > 1,000,000 < 0.005