Abstract：
BACKGROUND:The recent interest of clinical laboratories in developing serum testosterone assays based on isotope dilution-liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS) stems from the lack of accuracy of direct immunoassays. In this study, we assessed the accuracy and state of standardization (traceability) of 4 published ID-LC-MS/MS procedures in a method comparison with an ID-gas chromatography (GC)-MS reference measurement procedure listed in the database of the Joint Committee for Traceability in Laboratory Medicine. METHODS:The study used 58 specimens from different patient categories. Each specimen was measured in triplicate (ID-LC-MS/MS) and quadruplicate (ID-GC-MS) in independent runs. RESULTS:The testosterone concentrations by ID-GC-MS were 0.2-4.4 nmol/L (women), 0.2-2.0 nmol/L (hypogonadal man), and 10.1-31.3 nmol/L (normogonadal men). For ID-GC-MS, the CV was nearly constant, with a median of 1.0%; for ID-LC-MS/MS, it was concentration-dependent, with a median of up to 8%. Weighted Deming regression gave mean slopes, intercepts, and correlation coefficients of 0.90-1.11, -0.055-0.013 nmol/L, and 0.993-0.997, respectively. The % difference plot showed between 7% and 26% of the results outside a total error limit of 14%, with median deviations from ID-GC-MS between -9.6 and 0.4%. CONCLUSIONS:This study demonstrated fairly good accuracy and standardization of the tested ID-LC-MS/MS procedures. Performance differences between procedures were evident in some instances, due to improper calibration and between-run calibration control. This emphasizes the need for thorough validation, including traceability, of new ID-LC-MS/MS procedures.
journal_name
Clin Chemjournal_title
Clinical chemistryauthors
Thienpont LM,Van Uytfanghe K,Blincko S,Ramsay CS,Xie H,Doss RC,Keevil BG,Owen LJ,Rockwood AL,Kushnir MM,Chun KY,Chandler DW,Field HP,Sluss PMdoi
10.1373/clinchem.2008.105841subject
Has Abstractpub_date
2008-08-01 00:00:00pages
1290-7issue
8eissn
0009-9147issn
1530-8561pii
clinchem.2008.105841journal_volume
54pub_type
杂志文章abstract：BACKGROUND:The ratio of plasma aldosterone concentration to plasma renin activity (PRA) is considered the screening test of choice for primary aldosteronism. Uncertainty exists, however, regarding its diagnostic accuracy and the effects of antihypertensive drugs and dietary sodium balance on test characteristics. METH...
journal_title：Clinical chemistry
pub_type： 临床试验,杂志文章
doi：10.1373/clinchem.2004.041780
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abstract：:We measured cyclosporine in whole blood from normal volunteers administered single oral doses of the drug and from two renal-transplant patients on immunosuppressive maintenance therapy, by liquid chromatography (I) and by radioimmunoassay with use of nonspecific polyclonal (II), specific monoclonal (III), and nonspec...
journal_title：Clinical chemistry
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更新日期：1987-12-01 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...
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journal_title：Clinical chemistry
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doi：
更新日期：1995-09-01 00:00:00
abstract：:We have reported (Clin Chem 29: 42-44, 1983) that prestaining with Remazol Brilliant Blue permits direct visualization of serum components on disc electrophoresis, and apparently purifies the proteins well. Here we have cut out the bands corresponding to the prestained albumin and transferrin after disc electrophoresi...
journal_title：Clinical chemistry
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doi：
更新日期：1984-07-01 00:00:00
abstract：BACKGROUND:A single nonfunctional chimeric gene with its 5' and 3' ends corresponding to CYP21P and CYP21, respectively, is caused by unequal gene crossover in the CYP21 genes during meiosis. The presence of the chimeric CYP21P/CYP21 molecule can not be detected by conventional PCR methods and therefore may be lost in ...
journal_title：Clinical chemistry
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更新日期：2000-05-01 00:00:00
abstract：:We studied the pattern of acute-phase proteins (orosomucoid, C-reactive protein, and haptoglobin) in hepatocellular deficiency due to chronic alcohol consumption, characterized by a decrease in serum transferrin concentration. We found that their patterns could vary independently of hepatocellular deficiency, but depe...
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doi：
更新日期：1983-01-01 00:00:00
abstract：:A convenient screening procedure for presence of drugs of abuse in urine consists of two steps: adsorption of the drugs from urine onto a paper loaded with cation-exchange resin and detection of the adsorbed drugs by direct radioimmunoassay. The first step can be performed in the field, the second in a central laborat...
journal_title：Clinical chemistry
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doi：
更新日期：1977-10-01 00:00:00
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journal_title：Clinical chemistry
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doi：
更新日期：1989-08-01 00:00:00
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pub_type： 临床试验,杂志文章
doi：
更新日期：1999-10-01 00:00:00
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journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1982-07-01 00:00:00
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journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1978-02-01 00:00:00
abstract：:We report the production and comparative specificities of antisera raised to different immunogens containing codeine, morphine, and oxycodone. Antisera raised to bovine serum albumin (BSA) conjugates of codeine-6-hemisuccinate, ethylmorphine-6-hemisuccinate, or oxycodone-6-carboxymethyloxime had greatest recognition o...
journal_title：Clinical chemistry
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doi：
更新日期：1981-09-01 00:00:00
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journal_title：Clinical chemistry
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doi：
更新日期：2000-04-01 00:00:00
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journal_title：Clinical chemistry
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doi：10.1373/clinchem.2016.261636
更新日期：2017-01-01 00:00:00
abstract：BACKGROUND:High-resolution DNA melting analysis of small amplicons is a simple and inexpensive technique for genotyping. Microfluidics allows precise and rapid control of temperature during melting. METHODS:Using a microfluidic platform for serial PCR and melting analysis, 4 targets containing single nucleotide varian...
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更新日期：2017-10-01 00:00:00
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journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2010.156034
更新日期：2011-04-01 00:00:00
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journal_title：Clinical chemistry
pub_type： 临床试验,杂志文章
doi：
更新日期：1999-07-01 00:00:00
abstract：:A coated microtiter-well, enzyme-linked immunometric assay for quantifying immunoreactive trypsinogen in dried blood spots was modified to use time-resolved fluorescence of europium in place of end-point enzymatic color development as the quantification step. The streptavidin-horseradish peroxidase and color developme...
journal_title：Clinical chemistry
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doi：
更新日期：1993-02-01 00:00:00
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journal_title：Clinical chemistry
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doi：10.1373/clinchem.2003.023853
更新日期：2004-02-01 00:00:00
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更新日期：2017-05-01 00:00:00
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journal_title：Clinical chemistry
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doi：
更新日期：1977-09-01 00:00:00
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journal_title：Clinical chemistry
pub_type： 杂志文章,随机对照试验
doi：10.1373/clinchem.2014.234955
更新日期：2015-04-01 00:00:00
abstract：BACKGROUND:Tamoxifen is a standard endocrine therapy for the prevention and treatment of steroid hormone receptor-positive breast cancer. CONTENT:Tamoxifen requires enzymatic activation by cytochrome P450 (CYP) enzymes for the formation of active metabolites 4-hydroxytamoxifen and endoxifen. As compared with the paren...
journal_title：Clinical chemistry
pub_type： 杂志文章,评审
doi：10.1373/clinchem.2008.121756
更新日期：2009-10-01 00:00:00
abstract：BACKGROUND:False-positive results are a common problem in real-time PCR identification of DNA sequences that differ from near neighbors by a single-nucleotide polymorphism (SNP) or deletion. Because of a lack of sufficient probe specificity, post-PCR analysis, such as a melting curve, is often required for mutation dif...
journal_title：Clinical chemistry
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doi：10.1373/clinchem.2007.091488
更新日期：2007-12-01 00:00:00
abstract：:A simple and convenient method using commercially available derivatization reagents is described for the measurement of betaine and N,N-dimethylglycine (DMG) in blood and urine. Precolumn derivatization of plasma or urine is performed directly in acetonitrile without extraction with p-bromophenacyl bromide and crown e...
journal_title：Clinical chemistry
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doi：
更新日期：1998-09-01 00:00:00
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journal_title：Clinical chemistry
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doi：10.1373/clinchem.2015.239459
更新日期：2015-11-01 00:00:00
abstract：:A highly sensitive two-site sandwich ELISA measuring total proinsulin immunoreactive material in serum or plasma was developed. The assay was based on two monoclonal antibodies, an anti-C-peptide antibody bound to a microtest plate and a biotin-labeled anti-insulin antibody. The detection limit (3 SD above zero value)...
journal_title：Clinical chemistry
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doi：
更新日期：1993-10-01 00:00:00
