G. Wang, M. Vincent, A. Agrawal, C. Castro, C. R. Henry, C. Moore, Immunalysis Corporation, 829 Towne Center Drive, Pomona, CA 91767
Introduction
Hair is a useful specimen for the detection of long-term drug use. In general, drug concentrations in hair are lower than those identified in other matrices such as urine and blood. Further, specimen volume may be limited, so sensitive screening methods are necessary. Following METH use, METH itself is generally found in hair, but AMP may be present as a metabolite, or as an independent drug.
Methods
- Hair from METH users (n = 20; 10mg); Drug free hair (n = 20; 10 mg)
- Cut into small pieces; 0.1 M phosphate buffer added (pH 2.7; 0.5 mL)
- Incubated (3 hrs/75oC).
- Supernatant was analyzed using two ELISA and two homogeneous immunoassays (EIA) on an Olympus 400 platform
- One for METH; One for AMP
- For ELISA, the supernatant was diluted 1:5 with PBS before plating
- For EIA, 10mL of supernatant was used, making the process compatible with most commercial chemistry analyzers
Cross-reactivity
Results
- A screening cutoff of 500 pg/mg was used, (recommendation from the Proposed Federal Guidelines 2004)
- Precision at 250, 500, 1000, 2500 pg/mg
- AMP EIA Intra-assay: 9.9%, 8.2%, 6.6%, 3.7%; METH EIA Intra-assay: 11.6%, 8.3%, 7.1%, 2.7%
- All the negative specimens screened negatively using both ELISA and EIA; positive specimens are shown below
Summary: The assay is precise, sensitive and conducive to rapid hair screening using commercial chemistry analyzers
Disclosure: Immunalysis Corporation manufactures and distributes the immunoassays described in this presentation
SOFT 2008
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