Abstract：
:We tested 231 urine samples by six immunoassay methods--EMIT d.a.u., EMIT II, Roche Abuscreen Online, Abbott TDx, Diagnostic Products Corp. (DPC) double-antibody radioimmunoassay (RIA), and Biosite Triage--and by negative chemical ionization gas chromatography/mass spectrometry to determine how the immunoassays performed on samples selected for suspected benzodiazepine use (n = 100) and in random urine drug screening (n = 131). In general, all of the assays were successful in detecting oxazepam and related metabolites, even at concentrations below the stated cutoffs. However, the negative predictive value of benzodiazepine immunoassays for samples selected for suspected benzodiazepine use ranged from 86% to 96%. A primary difference between the test kits was the ability of DPC RIA and Triage to detect lorazepam when other assays did not. Contrary to previous reports, pretreatment of specimens with glucuronidase was not necessary to detect oxazepam-related metabolites with these immunoassays.
journal_name
Clin Chemjournal_title
Clinical chemistryauthors
Fitzgerald RL,Rexin DA,Herold DAsubject
Has Abstractpub_date
1994-03-01 00:00:00pages
373-80issue
3eissn
0009-9147issn
1530-8561journal_volume
40pub_type
杂志文章abstract：BACKGROUND:Adequate detection of designer steroids in the urine of athletes is still a challenge in doping control analysis and requires knowledge of steroid metabolism. In this study we investigated whether uPA(+/+)-SCID mice carrying functional primary human hepatocytes in their liver would provide a suitable alterna...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2008.119396
更新日期：2009-10-01 00:00:00
abstract：:We measured the concentration of erythrocyte protoporphyrin in 43 blood samples by two fluorometric methods. In the indirect method, protoporphyrin was extracted from blood and the fluorescence of the free acid in the extract was determined with a filter-fluorometer. These results were compared with results of direct ...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1978-09-01 00:00:00
abstract：:We present evidence for the utility of an improved assay for the activity of lactate dehydrogenase (EC 1.1.1.27) isoenzymes 1 and 2 in serum, involving inhibition of the H-subunit of LD by pyruvate at pH 7.1. Results correlate well with the LD-1/total LD ratio as evaluated by immunological assay and, as an index to in...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1986-05-01 00:00:00
abstract：BACKGROUND:Small RNAs are key players in the regulation of gene expression and differentiation. However, many different classes of small RNAs (sRNAs) have been described with distinct biogenesis pathways and, as a result, with different biochemical properties. To analyze sRNAs by deep sequencing, complementary DNA synt...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2019.305045
更新日期：2019-12-01 00:00:00
abstract：:We describe specifications for high-purity 4-nitrophenol, which is suitable for spectrophotometric standardization. Such a reference material is needed in clinical enzymology to establish the proper molar absorptivity of 4-nitrophenol under final reaction conditions, particularly for measuring alkaline phosphatase act...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1980-05-01 00:00:00
abstract：:We developed a simple method for the analysis of bismuth (Bi) in biological tissue, using wet digestion for sample pretreatment. Bi was determined by electrothermal atomic absorption spectrometry with platinum as a matrix modifier to decrease the volatility of Bi. The furnace program included a gas stop for sensitivit...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1993-05-01 00:00:00
abstract：:To validate azotemic markers as an index for intradialytic changes in solute concentration, we compared eight solutes (pseudouridine, xanthine, hypoxanthine, peak 4, peak 5, p-hydroxyhippuric acid, indoxyl sulfate, and hippuric acid) with five classical azotemic markers (urea, creatinine, uric acid, phosphate, and pot...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1992-08-01 00:00:00
abstract：BACKGROUND:Although numerous lateral flow immunoassays (LFIAs) have been developed and widely used, inadequate analytical sensitivity and the lack of multiple protein detection applications have limited their clinical utility. We developed a new LFIA device for the simultaneous detection of high-sensitivity cardiac tro...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2011.171694
更新日期：2011-12-01 00:00:00
abstract：:We report a survey on urine drug testing within a total of 269 laboratories of the European Union. Clinical laboratories predominated over forensic laboratories (59.5% vs 28.5%). Screening without identification/quantification was the common approach used by clinical laboratories, whereas screening with identification...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1998-04-01 00:00:00
abstract：:We evaluated the EMIT (enzyme-multiplied immuno technique) and FPIA (fluorescence polarization immunoassay) urine screening systems for detection of benzodiazepine intake. Healthy male volunteers were given single oral therapeutic doses of alprazolam (2 mg), chlordiazepoxide (25 mg), flunitrazepam (1 mg), lorazepam (3...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1992-02-01 00:00:00
abstract：BACKGROUND:Plasma B-type cardiac natriuretic peptides reflect cardiac structure and function and have proven roles in assisting in the diagnosis of acute heart failure. They are independent prognostic indicators across the full spectrum of cardiovascular disease. Serial changes in plasma B-type cardiac natriuretic pept...
journal_title：Clinical chemistry
pub_type： 杂志文章,评审
doi：10.1373/clinchem.2011.165704
更新日期：2012-01-01 00:00:00
abstract：:The isoenzymes of lactate dehydrogenase (EC 1.1.1.27) were separated with excellent resolution in less than 1 h by high-pressure anion-exchange chromatography. These isoenzymes were determined in some tissue extracts and high-activity serum samples by this technique. ...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1976-04-01 00:00:00
abstract：:We evaluated the analytical performance of new estradiol and progesterone assays performed on the Bayer Immuno 1 system. Within-run and between-day CVs for estradiol at concentrations of 116.8-6645.8 pmol/L were < or = 6.4% and for 5.54-103.95 nmol/L progesterone were < or = 7.7%, thus meeting published analytical goa...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1997-09-01 00:00:00
abstract：BACKGROUND:Testing for troponin has important clinical value for patients who present with typical symptoms of acute coronary syndromes (ACS) such as chest pain (CP). Much less is known about the value of troponin testing for patients who present with other symptoms of ACS (anginal equivalent symptoms). METHODS:The ut...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2003.016311
更新日期：2004-01-01 00:00:00
abstract：:We review the following labels used as substitutes for radioisotopes in immunoassay systems: bacteriophages, chemiluminescence precursors, fluorochromes, fluorogens, fluorescence quenchers, enzymes, coenzymes, inhibitors, substrates, various particulates, metal atoms, and stable free radicals. New methods for performi...
journal_title：Clinical chemistry
pub_type： 杂志文章,评审
doi：
更新日期：1981-07-01 00:00:00
abstract：:Determination of zinc in blood plasma by flameless atomic absorption spectrometry is discussed, with particular reference to the protocol required for the successful use of the Varian-Techtron Carbon Rod Atomizer. Cup aging is shown to be an important factor in limiting the precision of this analytical technique and ...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1975-04-01 00:00:00
abstract：:This new assay procedure for diaphorase eliminates problems of high blank rates and nonlinear kinetics associated with other methods. The dye thiazolyl blue tetrazolium bromide is reduced in the presence of NADH and diaphorase to yield a colored formazan, which as maximum absorbance at 560 nm. ...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1979-12-01 00:00:00
abstract：:The contribution of the exocrine pancreas to hyperamylasemia in diabetic ketoacidosis was investigated by measuring total amylase, salivary and pancreatic isoamylases, cathodic trypsin-like immunoreactivity, and pancreatic lipase in 12 consecutive patients recovering from diabetic ketoacidosis. Hyperamylasemia was pre...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1985-12-01 00:00:00
abstract：BACKGROUND:Sensitive and specific biomarkers for the early detection of esophageal squamous cell carcinoma (ESCC) are urgently needed to reduce the high morbidity and mortality of the disease. The discovery of serum microRNAs (miRNAs) and their unique concentration profiles in patients with various diseases makes them ...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2010.147553
更新日期：2010-12-01 00:00:00
abstract：:We have observed an electrophoretically abnormal, nonfunctional species of alpha 1-antitrypsin in serum from patients who were receiving bone-marrow transplants for treatment of leukemia or aplastic anemia. Three of four patients in whose serum this protein appeared died soon after; the fourth recovered, and the disap...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1987-01-01 00:00:00
abstract：:We measured thyroid hormones and thyroxin-binding proteins in serum from 62 normal lactating and 52 nonlactating women at three months postpartum, and compared these values with those for 42 nonpregnant control women of similar age. Mean thyroxin concentrations in the lactating and nonlactating women were significantl...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1987-07-01 00:00:00
abstract：BACKGROUND:Galectin-3 has emerged as a potential useful novel biomarker for heart failure and cardiovascular disease (CVD). However, it remains unclear whether galectin-3 is associated with recurrent cardiovascular events during long-term follow-up of patients with stable coronary heart disease (CHD) after adjustment f...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2016.257550
更新日期：2016-10-01 00:00:00
abstract：:We describe a mass-fragmentographic method for determination in urine of the following metabolites of L-3,4-dihydroxyphenylalanine and dopamine: vanillactic acid, 3,4-dihydroxyphenylacetic acid, 3-methoxy-4-hydroxyphenylethanol, and 3,4-dihydroxyphenylethanol. Deuterated analogs were used as internal standards. The me...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1978-01-01 00:00:00
abstract：BACKGROUND:Gradient gel electrophoresis (GGE) and nuclear magnetic resonance (NMR) spectroscopy are both widely accepted methods for measuring LDL and HDL particle size. However, whether or not GGE- or NMR-measured LDL or HDL particle size predicts coronary heart disease (CHD) risk to a similar extent is currently unkn...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2009.140939
更新日期：2010-05-01 00:00:00
abstract：:We measured morphine and codeine in commercially available poppy seeds and in serum and urine samples from healthy adults who had ingested these poppy seeds. Four brands of black poppy seeds, examined by gas chromatography-mass spectroscopy (GC-MS) with deuterated internal standards, contained from 17 to 294 microgram...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1987-06-01 00:00:00
abstract：:We describe a new liquid-chromatographic method with fluorescence detection for direct simultaneous determination of four urinary sulfate conjugates of 17-oxosteroids (17OS), without use of solvolysis or enzymatic hydrolysis. The 17OS sulfates in urine samples are extracted with benzene as ion pairs in the presence of...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1986-05-01 00:00:00
abstract：:17 alpha-Hydroxyprogesterone, cortisol, and 11-deoxycortisol were extracted with methylene chloride, separated by liquid chromatography, identified by their retention times, and quantitated by monitoring the absorbance at 254 nm. The method is specific and sensitive to as little as 2.5 ng of 17 alpha-hydroxyprogestero...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1981-07-01 00:00:00
abstract：:To establish optimum conditions for creatine kinase (EC 2.7.3.2) activity measurement with the creatine phosphate in equilibrium creatine reaction, we re-examined all kinetics factors relevant to an optimal and standardized enzyme assay at 30 and 25 degrees C. We determined the pH optimum in vaious buffers, considerin...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1976-05-01 00:00:00
abstract：BACKGROUND:Quantification of integrated proviral HIV DNA by repetitive-sampling Alu-HIV PCR is a candidate virological tool to monitor the HIV reservoir in patients. However, the experimental procedures and data analysis of the assay are complex and hinder its widespread use. Here, we provide an improved and simplified...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2013.219378
更新日期：2014-06-01 00:00:00
abstract：:We describe a chromatographic system involving a high-performance chemically-bonded reverse-phase column and fluorescence detection for measurement of indoles in urine. We controlled retention and selectivity by optimizing the methanol content and pH of the mobile phase. Six reference indoles were separated in less th...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1976-02-01 00:00:00
