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The Quest Diagnostics HairCheck-DT (Cocaine) test system utilizes an Enzyme Linked Immunosorbent Assay (ELISA) for the qualitative detection of cocaine in head hair samples through the measurement of cocaine and cocaine metabolites for concentrations at or above 300 pg/mg hair. This test system has not been evaluated for use with hair specimens from locations other than the head. It is an in vitro diagnostic device intended exclusively for in-house professional use and is not intended for sale to anyone. The HairCheck-DT (Cocaine) test system was evaluated in two distinct study populations; individuals known to be chronic drug abusers, and individuals proclaiming to be drug-free. The Quest Diagnostics HairCheck-DT (Cocaine) test system provides only a preliminary analytical test result. To confirm a presumptive screen positive result, a more specific alternate chemical method, such as gas chromatography-mass spectrometry (GC-MS) or Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS), must be used. Clinical consideration and professional judgment should be applied to any drug of abuse test result, particularly when preliminary positive results are obtained.

The Quest Diagnostics Hair Check-DT (Cocaine) test system utilizes an Enzyme Linked Immunosorbent Assay (ELISA) for the qualitative detection of cocaine in head hair samples through the measurement of cocaine and cocaine metabolites for concentrations at or above 300 pg/mg hair. This test system has not been evaluated for use with hair specimens from locations other than the head. It is an in vitro diagnostic device intended exclusively for in-house professional use and is not intended for sale to anyone. The ELISA Cocaine Kit is based on the competition for a limited number of antibody sites by unlabeled cocaine/cocaine metabolites and enzyme-labeled drug. The two will bind to the antibody in proportion to their concentration in solution. Once accessioned in the lab, the aluminum foil is opened and the specimen is cut at approxima 3.9 cm from the root end. This specimen is cut into smaller lengths and mixed to ens homogeneity. Ten milligrams of the specimen is weighed out and placed into a properly labeled test tube. The specimen is then washed with methanol, decanted, and then placed in hot methanol containing 0.5% (v/v) trifluoroacetic acid for one hour forty-five minutes. The extracted methanol solution is then transferred to a new tube and evaporated under nitrogen. The tubes are reconstituted with phosphate buffer and assayed using the Cocaine ELISA Kit. This kit is a solid-phase microtiter plate immunoassay in which the microwells are coated with a high affinity capture antibody to cocaine. A hair sample extract is added to the well, followed by the horseradish peroxidase (HRP) enzyme conjugate. During this initial phase, the enzyme conjugate competes with the analyte in the sample for binding sites on the antibody-coated microwells. A wash solution (Tween-20 in phosphate buffered saline solution) is then applied to remove any unbound materials such as excess conjugate and residual sample. Enzyme substrate solution containing 3, 3', 5, 5'-tetramethylbenzidine (TMB) is then added for the final color development process. The reaction is stopped with 1N sulfuric acid and the absorbance is read at 450 nm, with a reference wavelength of 620 nm, using a plate reader. Color intensity is inversely proportional to the amount of analyte present in the sample. Therefore, samples that contain drug or analyte will inhibit binding of the enzyme conjugate to the antibody, resulting in little substrate binding and less color development than in the negative calibrator. For the screening assay an absorbance less than or equal to the absorbance of the 300 pg cocaine/mg hair cutoff calibrator is indicative of the presence of cocaine/cocaine metabolites.