Frontline immunochromatographic device for on-site urine testing of amphetamines: laboratory validation using...

Area of Science:

• Clinical Chemistry
• Forensic Toxicology
• Analytical Chemistry

Background:

• Rapid screening tests are crucial for detecting amphetamines and methamphetamines in clinical and forensic settings.
• Immunochromatographic devices offer a quick, visual method for drug testing.
• Accurate performance evaluation of new screening devices is essential.

Purpose of the Study:

• To evaluate the performance of a new immunochromatographic test device (Frontline) for detecting amphetamines and methamphetamines.
• To compare the Frontline device results with established immunoassays and gas chromatography methods.
• To assess the device's sensitivity, specificity, and agreement across different drug concentration levels.

Main Methods:

• Utilized 658 authentic clinical and forensic urine specimens.
• Compared the Frontline test results against established immunoassays.
• Investigated discordant results using gas chromatography-mass spectrometry (GC-MS) or gas chromatography-flame ionization detection (GC-FID).

Main Results:

• The Frontline device demonstrated a sensitivity of 93% and a specificity of 98%.
• High agreement was observed at amphetamine concentrations below 150 ng/mL and above 1000 ng/mL.
• A subset of specimens with concentrations between 300-1000 ng/mL yielded false-negative results, potentially due to antibody enantioselectivity towards d-amphetamine.

Conclusions:

• The Frontline test device provides adequate performance for presumptive screening of amphetamines and methamphetamines.
• The observed discrepancies in the mid-range concentration zone warrant consideration in interpretation.
• Further investigation into the enantioselectivity of antibodies is recommended for optimizing test accuracy.