Biomedical subjects
Publications and source records attributed to Timothy P Lyons.
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Extraction of amphetamine and methamphetamine in urine was investigated using Cerex Polycrom Clin II solid-phase extraction columns and the Speedisk 48 Pressure Processor as a replacement for our liquid-liquid procedure. Linearity for urine standards extracted with the Cerex-Speedisk method ranged from 50 ng/mL for methamphetamine and from 150 ng/mL for amphetamine to 10,000 ng/mL for both. The mean recovery at the 500-ng/mL cutoff for three different lots of columns was 96.4% for AMP and 95.7% for MET. The mean of the within-run means for three batches was 495.4 ng/mL with a coefficient of variation (CV) of 1.2% or less for amphetamine and 496.4 ng/mL for methamphetamine with a CV of 1.7% or less. Thirty-six specimens containing amphetamine and the same number for methamphetamine were analyzed by both the Cerex-Speedisk and liquid-liquid methods. The correlation for specimens containing amphetamine gave an r2 of 0.9986 with a slope of 0.99; for methamphetamine, the r2 was 0.9997 with a slope of 0.98. The Cerex-Speedisk method cut extraction time in half, was less costly, and greatly reduced the volume of hazardous waste.
This article examines the positive rate by drug for all urinalysis specimens tested by the U.S. Army from fiscal year 1991 (FY91) to FY00 and for the Army National Guard (NG) from FY97 to FY00. The average positive rate for the Army from FY91 to FY00 was 0.84%. In FY00, the Army rate reached a 10-year high of 1.04%. From FY97 to FY00, the NG positive rate declined from 3.4% to 2.16% but was significantly (p < 0.05) higher than the Army rate during the same period. Marijuana and cocaine are the most abused drugs for both the Army and NG. The positive rate for marijuana in the Army from FY91 to FY00 was 0.51%, and the cocaine rate was 0.19%. The NG marijuana-positive rate from FY97 to FY00 was 1.70%, and the cocaine rate was 0.51%. The positive rate for all other drugs of abuse tested was less than 0.3% for both the Army and NG during the same periods. The overall positive rate for the Army and NG are below those estimated (6.3%) in the civilian population.