Urry F M, Kralik M, Wozniak E, Crockett H, Jennison T A
Associated Regional and University Pathologists, Inc. (ARUP), Salt Lake City, UT 84108.
J Anal Toxicol. 1993 Sep;17(5):287-91. doi: 10.1093/jat/17.5.287.
The performance of the Technicon Chem 1+ chemistry analyzer with the Syva Emit ethyl alcohol assay in plasma and urine was evaluated. Spiked specimens from 0 to 600 mg/dL were tested, and expected versus measured concentrations were monitored. Linear regression line equations of y = 0.9314x + 5.4 and y = 0.9005x + 4.6, and correlation coefficients (r) of 0.9997 and 0.9995, were obtained for plasma and urine, respectively. A limit of detection of 5 mg/dL for plasma and urine, and a limit of quantitation of 20 mg/dL for plasma and 15 mg/dL for urine were obtained. Recovery was within 10% of expected concentration from 20 to 600 mg/dL. Precision was evaluated, giving the following coefficients of variation: within-run precision: plasma, 1.31-2.20; urine, 1.16-1.21; total precision: plasma, 2.72-3.38; urine, 2.98-4.64. No carry-over was detected when alternating 600 mg/dL and negative specimens. No interference from acetone, isopropanol, or methanol was detected. No significant differences in evaporation of alcohol at two concentrations, or from the two matrices were observed. Evaporation from a small cup (200 microL) was more than twice as great as from a large cup (2 mL). The Chem 1+ was compared to a gas chromatographic method. Plasma specimens of 0-352 mg/dL produced a linear regression line of y = 1.0112x + 6.0, r = 0.9859; urine specimens of 0-313 mg/dL produced a line of y = 1.0493x - 0.3, r = 0.9910. The capability to separate positive and negative specimens at 20% around a cutoff concentration of 20 mg/dL was examined. Four hundred specimens were analyzed, with only one specimen incorrectly classified (a false positive). The Chem 1+ chemistry analyzer demonstrated reliable performance of the Emit ethyl alcohol assay of plasma and urine specimens.
