Abstract：
BACKGROUND:The accurate and precise measurement of urinary albumin is critical, since even minor increases are diagnostically sensitive indicators of renal disease, cardiovascular events, and risk for death. To gain insights into potential measurement biases, we systematically compared urine albumin measurements performed by LC-MS, a clinically available immunoturbidimetric assay, and size-exclusion HPLC. METHODS:We obtained unused clinical urine samples from 150 patients who were stratified by degrees of albuminuria (<20 mg/L, 20-250 mg/L, >250 mg/L) as determined by the immunoturbidimetric assay used in our clinical laboratory (Roche Hitachi 912). Urine albumin was then remeasured via LC-MS and HPLC (Accumin) assays. RESULTS:The immunoturbidimetric assay, calibrated using manufacturer-supplied serum-derived calibrators (Diasorin), underestimated albumin compared with LC-MS. After calibration with purified HSA, this immunoturbidimetric assay correlated well with LC-MS. HPLC overestimated albumin compared with both LC-MS and immunoturbidimetry. The current LC-MS and HPLC assays both performed poorly at concentrations <20 mg/L. CONCLUSIONS:Efforts are needed to establish gold-standard traceable calibrators for clinical assays. LC-MS is a specific method to quantify albumin in native urine when concentrations exceed 20 mg/L, and therefore could be employed for standardization among assays.
journal_name
Clin Chemjournal_title
Clinical chemistryauthors
Shaikh A,Seegmiller JC,Borland TM,Burns BE,Ladwig PM,Singh RJ,Kumar R,Larson TS,Lieske JCdoi
10.1373/clinchem.2008.107508subject
Has Abstractpub_date
2008-09-01 00:00:00pages
1504-10issue
9eissn
0009-9147issn
1530-8561pii
clinchem.2008.107508journal_volume
54pub_type
杂志文章abstract：BACKGROUND:D-2-Hydroxyglutaric aciduria (D-2-HGA), L-2-hydroxyglutaric aciduria (L-2-HGA), and the combined D/L-2-hydroxyglutaric aciduria (D/L-2-HGA) are poorly understood organic acidurias. To investigate the usefulness of cultured human skin fibroblasts for both diagnostic and research purposes, we measured disease-...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/49.7.1133
更新日期：2003-07-01 00:00:00
abstract：:I developed a standard procedure for assessing sensitivity, intra-assay precision, parallelism of sample dilutions, and assay drift, using a single trial assay kit. I used this to compare the performance of 10 commercial kits with an in-house radioimmunoassay for human thyrotropin. No one kit stood out as clearly supe...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1988-01-01 00:00:00
abstract：BACKGROUND:With the gradual reopening of economies and resumption of social life, robust surveillance mechanisms should be implemented to control the ongoing COVID-19 pandemic. Unlike RT-qPCR, SARS-CoV-2 whole genome sequencing (cWGS) has the added advantage of identifying cryptic origins of the virus, and the extent o...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1093/clinchem/hvaa187
更新日期：2020-11-01 00:00:00
abstract：:We examined the relationship between analytical sensitivity, precision at the lower limit of the reference interval, and diagnostic performance in hyperthyroidism for one radioimmunoassay and five immunometric assay kits for thyrotropin. The analytical sensitivity of these kits extended from 0.05 to 1.56 milli-int. un...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1988-07-01 00:00:00
abstract：:Over the past decade, significant improvements in immunochemical and electrophoretic techniques have enabled collection of heretofore unavailable data on proteins in biological fluids, greatly increasing our understanding of protein physiology in the various body compartments and providing the foundation for clinical ...
journal_title：Clinical chemistry
pub_type： 杂志文章,评审
doi：
更新日期：1982-05-01 00:00:00
abstract：:This rapid radioimmunoassay for aldosterone is performed directly on 100 microL of unprocessed plasma, with 125I-labeled aldosterone as the labeled antigen. Our use of steroid-free plasma in preparing the standard curve resulted in an overestimate of aldosterone; this problem was overcome by adding to such plasma a mi...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1983-02-01 00:00:00
abstract：BACKGROUND:The kidney performs a multitude of essential functions to maintain homeostasis. In clinical medicine, glomerular filtration rate (GFR) provides the best index of overall kidney function, and proteinuria adds additional information on renal and nonrenal prognosis. Several novel biomarkers of kidney injury and...
journal_title：Clinical chemistry
pub_type： 杂志文章,评审
doi：10.1373/clinchem.2011.167494
更新日期：2012-04-01 00:00:00
abstract：:In this liquid-chromatographic method for the determination of bromide in human serum, an important and unique feature is pre-analysis ultrafiltration of the sample, which effectively removes proteins. The chromatographic system consists of an anion-exchange column (Whatman Partisil SAX 10-micron particles), an isocra...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1984-05-01 00:00:00
abstract：:Sensitivity, stability, and specificity of the color-producing reaction of hydrogen peroxide with bezidine, leuco-malachite green, or o-dianisidine were tested in numerous systems containing hemoglobin and other hemoproteins. Use of urea or low temperature (to minus 12 degrees C), or both, was highly beneficial, espec...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1975-03-01 00:00:00
abstract：:Radioimmunoassay of triiodothyronine was performed with a homogeneous incubation system. Bound and free ligand were separated by partitioning in an aqueous two-phase system. The agreement between the results obtained with this technique and conventional heterogeneous radioimmunoassay was very good (r = 0.981). ...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1982-04-01 00:00:00
abstract：:Assays with different specificity are used for cyclosporin monitoring in clinical transplantation. A recent survey of 35 centers showed that 86% used immunoassays for cyclosporin A (CsA). In consensus documents the following performance criteria were recommended: (a) imprecision < or = 10% at 50 microg/L and < or = 5%...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1998-10-01 00:00:00
abstract：BACKGROUND:Consideration of circulating biomarkers for risk stratification in heart failure (HF) is recommended, but the influence of atrial fibrillation (AF) on prognostic performance of many markers is unclear. We investigated the influence of AF on the prognostic performance of circulating biomarkers in HF. METHODS...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1093/clinchem/hvaa287
更新日期：2021-01-08 00:00:00
abstract：:At the clinical level, we have seen the emergence of a subspecialty of affective disorders within psychiatry. Mood clinics, depression units, and affective disorders centers are appearing in many academic and clinical settings, where clinical skill and knowledge can be concentrated and new research furthered. By using...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1988-05-01 00:00:00
abstract：BACKGROUND:Proteomic technology permits the investigation of genetic metabolic diseases at the level of protein expression. Changes in the expression, polypeptide structure, and posttranslational modification of individual proteins can be detected in complex mixtures of proteins. METHODS:We used high-resolution two-di...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：2001-11-01 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：: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：:Creatine kinase isoenzyme BB (CK-BB) is found in the serum of patients with various types of cancer. Using both radioimmunoassay and agarose electrophoresis, we found abnormal amounts of this isoenzyme in the serum of 15 of 17 patients with untreated prostatic carcinoma. Among patients with other types of adenocarcino...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1979-08-01 00:00:00
abstract：:Direct-injection analysis for phenylalanine in plasma by isocratic "high-performance" liquid chromatography (HPLC) is described. For chromatographic separation I use an internal-surface reversed-phase silica support. The method involves ultraviolet detection, requires as little as 10 microL of plasma (routinely 20 mic...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1989-06-01 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：BACKGROUND:Recurrent pregnancy loss, (RPL) affecting 1%-2% of couples, is defined as ≥3 consecutive pregnancy losses before 20-week' gestation. Women with RPL are routinely screened for etiological factors, but routine screening of male partners is not currently recommended. Recently it has been suggested that sperm qu...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2018.289348
更新日期：2019-01-01 00:00:00
abstract：BACKGROUND:Hepcidin-25 reduces iron absorption by binding to the intestinal iron transporter ferroportin and causing its degradation. Currently, little is known about the basal regulation of circulating hepcidin-25. In addition, although erythropoietin administration has been reported to decrease the circulating hepcid...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2012.186866
更新日期：2012-08-01 00:00:00
abstract：BACKGROUND:Improved methods are required to screen drug candidates for their influences on protein interactions. There is also a compelling need for miniaturization of screening assays, with attendant reductions in reagent consumption and assay costs. METHODS:We used sensitive, miniaturized proximity ligation assays (...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2007.099424
更新日期：2008-07-01 00:00:00
abstract：BACKGROUND:A sensitive gas chromatography-negative ion chemical ionization mass spectrometry (GC/MS-NICI) method was developed and validated for the measurement of Delta(9)-tetrahydrocannabinol (THC) in human sweat patches. METHODS:THC-d(0) and THC-d(3) were added to worn blank sweat patches (PharmChek; PharmChem Inco...
journal_title：Clinical chemistry
pub_type： 临床试验,杂志文章
doi：10.1373/clinchem.2004.034868
更新日期：2004-11-01 00:00:00
abstract：BACKGROUND:Recent publications have explored the possibility of using fingerprints to confirm drug use, but none has yet dealt with environmental contamination from fingertips. Here we explored the possibility of establishing an environmental cutoff for drug testing from a single fingerprint. METHODS:Fingerprint sampl...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2017.281469
更新日期：2018-06-01 00:00:00
abstract：BACKGROUND:The American Diabetes Association task force on standardization of insulin assays in 1996 showed wide variation in assay bias. Newer assays are specific for insulin, with several now available on automated immunoassay analyzers. METHODS:In 2004, we compared 11 commercially available insulin assays by analyz...
journal_title：Clinical chemistry
pub_type： 杂志文章,多中心研究
doi：10.1373/clinchem.2006.077784
更新日期：2007-05-01 00:00:00
abstract：BACKGROUND:Blood concentrations of the calcineurin inhibitors (CNIs) cyclosporine and tacrolimus are currently measured to monitor immunosuppression in transplant patients. The measurement of calcineurin (CN) phosphatase activity has been proposed as a complementary pharmacodynamic approach. However, determining CN act...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2013.213264
更新日期：2014-02-01 00:00:00
abstract：:Published estimates of the imprecision characteristics of immunoassays are often based on quantities of data that seem to be inadequate. The increasing use of imprecision profiles has not necessarily improved the situation. We describe and illustrate a method of computing 95% confidence intervals for profiles estimate...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1990-07-01 00:00:00
abstract：:The core antigen component of hepatitis B virus (HBV), HBcAg, may be used as a marker of viral replication. We describe a radioimmunoassay for HBcAg in serum, and compare results with those by other similar methods. Samples are centrifuged over a sucrose gradient containing 2-mercaptoethanol, and the resulting pellets...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1985-06-01 00:00:00
abstract：:We report spectrophotometric methods for quantifying sodium and potassium in serum and plasma without sample pretreatment or solvent-extraction steps. The methods are based on novel chromogenic ionophores characterized by molecular structures highly preorganized for binding, which result in exceptionally high sensitiv...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1988-09-01 00:00:00
abstract：:Intra-erythrocytic pH, ATP concentrations, and 2,3-diphosphoglycerate relaxation times were studied in living erythrocytes by "high-resolution" 31P NMR spectroscopy to assess homeostasis within the cells. In uremic patients, intra-erythrocytic pH is significantly decreased before hemodialysis, but is corrected equally...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1987-01-01 00:00:00
