Screening for urinary amphetamine in truck drivers and drug addicts.

Sixty-two urine samples from truck drivers and drug addicts were analysed by TDx (Abbott Laboratories) for amphetamines. Eighteen samples were found to be positive while the rest were negative. The eighteen samples were simultaneously determined for amphetamines by EMIT (Syva Company). Sixteen samples were found to be positive and 2 of negative samples had amphetamines levels of 0.48-0.85 micrograms/mL. When the same samples were subjected to qualitative screening and some were found false negative as follows: 7 cases in Color Test by using test solution kits amphetamine in urine (the Department of Medical Science, Ministry of Public Health), 8 cases by Albuscreen Ontrax for amphetamine (Roche Diagnostic System), 5 cases by amphetamine Double Antibody 125I-RIA (Diagnostic Products Corporation-DPC) and 3 cases by the method of Ten-One (DPC) respectively. But when forty four samples which gave negative results by TDx were subjected to Testing by EMIT and Ontrax. The results of both EMIT and Ontrax were negative. Some of forty four samples were false positive by the Color Test solution kit amphetamines in urine and amphetamine Double Antibody 125I-RIA. Reliability of results reported not only depends on the methodology or principle but also the sensitivity of the method.

Laboratory evaluation of the COBAS MIRA S random access analyser.

The random access analyser COBAS MIRA S (Roche Diagnostics) was evaluated for two months. The instrument is a computer-controlled discrete analyser which can be run in a combination profile and single test mode. This instrument has special features, including an automatic cuvette segment changer, a reagent rack cooling system, an external keyboard and monitor, as well as a bar-code facility for the entry of test parameters, worklists and sample identification numbers. Study of within-run and between-run precision gave values of % CV 0.54-3.37 and 0.61-3.65, respectively, for a variety of assays. Linearity testing to the upper limit of each test was also studied and were found to cover the necessary pathological range. Within the two-month period, no major problems were encountered. The instrument required minimum operator attention during operation. Correlation studies with the Hitachi 705 using six clinical chemistry tests (glucose, cholesterol, triglyceride, ALP, AST, ALT) gave correlation coefficients ranging from 0.95-0.99 and slopes of 0.91-1.17.