Abstract：
BACKGROUND:We evaluated the analytical performance of 4 cystatin C assays (Siemens N Latex on BNII, Roche Tina-quant on Cobas c501, Genzyme on Cobas c501, and Tosoh ST AIA-PACK on Tosoh AIA-600II) according to guidelines published by the Clinical and Laboratory Standards Institute. METHODS:We evaluated total imprecision, limit of detection, and limit of quantification for each assay using patient serum pools and linearity/recovery using serial dilutions of a patient serum pool with cystatin C-free serum. We compared patients (n = 102) using the Siemens assay as a comparison method. RESULTS:All assays had limits of detection and quantification <0.08 and <0.39 mg/L, respectively. Total CVs were generally higher than the manufacturers' claims for all assays. The Roche assay overrecovered cystatin C, particularly at low concentrations (mean recovery 119%, 142% at 0.587 mg/L). Deming regression equations were y = 1.184x + 0.089, S(y|x) = 0.246 for Genzyme; y = 0.937x + 0.231, S(y|x) = 0.231 for Roche; and y = 1.010x + 0.216, S(y|x) = 0.115 for Tosoh. The Genzyme assay appeared to report higher results than the Siemens assay, which is consistent with a higher reference interval specified by the manufacturer. CONCLUSIONS:Although all assays were acceptable for clinical use, their diagnostic performances were not optimal. Limitations include imprecision greater than claimed, overrecovery for the Roche assay on low concentration samples, and differences in results for patient samples. The latter situation requires assay-specific cystatin C-based glomerular filtration rate prediction equations at least until calibration is standardized using the international cystatin C calibrator now being developed.
journal_name
Clin Chemjournal_title
Clinical chemistryauthors
Li J,Dunn W,Breaud A,Elliott D,Sokoll LJ,Clarke Wdoi
10.1373/clinchem.2009.141531subject
Has Abstractpub_date
2010-08-01 00:00:00pages
1336-9issue
8eissn
0009-9147issn
1530-8561pii
clinchem.2009.141531journal_volume
56pub_type
杂志文章abstract：:A modified agarose electrophoretic system for the separation of alkaline phosphatase (ALP, EC 3.1.3.1) isoenzymes is described. Bone, liver, high-molecular-mass, and intestinal ALP are separated with high reproducibility. The sensitivity of the agarose system is superior to cellulose acetate in detecting high-Mr ALP. ...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1988-09-01 00:00:00
abstract：BACKGROUND:The resurgence of the parasitic disease schistosomiasis calls for more efficient diagnostic tests. We developed a rapid, simple, portable, and sensitive immunoagglutination assay that uses SiO(2) particles and quartz crystal microbalance (QCM) for quantifying Schistosoma japonicum (Sj) antibodies (SjAb). ME...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2006.071555
更新日期：2006-11-01 00:00:00
abstract：BACKGROUND:Formation of deposits of the insoluble amyloid beta-peptide is believed to be causally related with neurodegeneration in Alzheimer disease (AD). The beta-peptide originates from a larger amyloid precursor protein (APP) by the action of proteolytic enzymes. The first proteolytic event leading to amyloid forma...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2006.066720
更新日期：2006-06-01 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：BACKGROUND:Oxidation of lipids in lipoproteins and cells may initiate and enhance the early development of cardiovascular disease. METHOD AND RESULTS:We assayed F(2)-isoprostanes, oxidation products of arachidonic acid, by gas chromatography-mass spectrometry in a biracial cohort of 2850 young healthy adult men and wo...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2004.037630
更新日期：2005-01-01 00:00:00
abstract：BACKGROUND:Calcitonin (CT) is a sensitive marker for evaluation of medullary thyroid cancer (MTC). However, CT measurement can vary with assay- and nonassay-dependent factors, and procalcitonin (PCT) measurement has been proposed for evaluating questionable increases in CT. METHODS:We tested 2 fully automated CT assay...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2010.151688
更新日期：2011-03-01 00:00:00
abstract：:Noninvasive monitoring of blood/tissue glucose concentrations has been successfully accomplished in individual diabetic subjects by using near-infrared (NIR) spectroscopy coupled with chemometric methods. Three different spectrometer configurations were tested: a) a Fourier-transform infrared spectrometer with an indi...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1992-09-01 00:00:00
abstract：BACKGROUND:Altered germline expression of genes may represent a powerful marker of genetic or epigenetic predisposition to cancer or other diseases. METHODS:We developed and validated a method of nonfluorescent primer extension that uses a single dideoxynucleotide and denaturing HPLC (DHPLC) to analyze the relative al...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2009.126300
更新日期：2009-09-01 00:00:00
abstract：:Determination of the MB isoenzyme of creatine kinase in patients with acute myocardial infarction may be disturbed by the presence of macro creatine kinase. The relative molecular mass of this form of creatine kinase in human serum is at least threefold that of the ordinary enzyme, and it is more thermostable. Here we...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1982-01-01 00:00:00
abstract：:This method for assaying digoxin in serum with improved specificity combines small-column extraction of serum, "high-performance" liquid chromatography, and RIA of the eluted fractions. Analytical recoveries of 1.0, 0.5, and 0.1 microgram/L standards were 95%, 93%, and 84%, respectively. The CVs for duplicates and rep...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1985-08-01 00:00:00
abstract：:We describe the process of certification for a gamma-glutamyltransferase reference material (CRM no. 319). Fifteen laboratories participated to this interlaboratory evaluation. All steps of the measurements were controlled in an effort to locate potential sources of variations. In particular, the exclusion of some dat...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1987-11-01 00:00:00
abstract：:Ethchlorvynol is a commonly abused sedative hypnotic. I report here a seven-day study of serum ethchlorvynol concentrations in a patient who had received an extreme overdose. These concentrations were correlated with the patient's response to stimuli. Serum ethchlorvynol concentrations were logarithmically related to ...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1975-06-01 00:00:00
abstract：:alpha 1-Antitrypsin (A1AT) deficiency is a relatively common autosomal recessive disease, resulting most often from a single base pair (1 bp) substitution called the Z mutation. Previous genetic tests for carriers and affected patients have relied on quantitative binding of radioactive probes to an amplified gene prod...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1992-08-01 00:00:00
abstract：BACKGROUND:Intravenous and subcutaneous microdialysis was performed to compare the free concentrations and pharmacokinetics of L-3, 4-dihyroxyphenylalanine (L-dopa) in blood and tissue in healthy subjects and in patients with Parkinson disease. METHODS:Nine healthy volunteers and 10 patients with Parkinson disease, st...
journal_title：Clinical chemistry
pub_type： 临床试验,杂志文章
doi：
更新日期：1999-10-01 00:00:00
abstract：:We determined the urinary excretion of 5-fluorouracil (5FU) and its metabolites during six days of chemotherapy, using the non-invasive approach of 19F nuclear magnetic resonance. With this method, which requires no labeled drug, one can study the biological sample directly and simultaneously identify and quantify all...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1985-06-01 00:00:00
abstract：:This paper reviews our ability to predict survival and neurodevelopmental outcome in the newborn period. Traditionally, prognosis is based on individual risk factors or disease states. The laboratory plays an important role in diagnosing some of these. For example, prenatal and newborn screening are important in the d...
journal_title：Clinical chemistry
pub_type： 杂志文章,评审
doi：
更新日期：1997-01-01 00:00:00
abstract：BACKGROUND:The emergence of a novel pandemic human strain of influenza A (H1N1/09) has clearly demonstrated the need for flexible tools enabling the rapid development of new diagnostic methods. METHODS:We designed a set of reverse-transcription quantitative real-time PCR (RT-qPCR) assays based on the Universal ProbeLi...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2009.136192
更新日期：2009-12-01 00:00:00
abstract：:We report another patient with a circulating alkaline phosphatase/immunoglobulin complex in his blood, and describe a simple method of demonstrating such complexes. On electrophoresis on cellulose acetate, the complex was relatively slow moving and there was no activity in the normal bone/liver isoenzyme region. When ...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1980-10-01 00:00:00
abstract：:We measured the rate of elimination of phenylalanine by constant intravenous infusion of L-phenylalanine in 14 parents of children with phenylketonuria and in 21 subjects with a negative family history for this disease. When reciprocals of the observed elimination rates were plotted against the reciprocals of the incr...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1977-09-01 00:00:00
abstract：:We evaluated the Reflotron (Boehringer Mannheim) system for measuring activities of alanine aminotransferase (EC 2.6.1.2) and gamma-glutamyltransferase (EC 2.3.2.2). Within- and between-day precision were comparable with conventional analytical methods. The linear range of the methods extended to more than 40-fold the...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1987-06-01 00:00:00
abstract：:We have improved the protocol for RNA quantification by using RNase protection. Instead of precipitation and extraction with phenol and chloroform, we use a faster and more reliable precipitation based on guanidinium thiocyanate (GdSCN). The internal standard is produced by in vitro transcription of a DNA template con...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1995-11-01 00:00:00
abstract：BACKGROUND:Few data compare cardiac troponin T (cTnT) and cardiac troponin I (cTnI) in a general population. We sought to evaluate the distribution and association between cTnT, cTnI, and cardiovascular risk factors in a large general population cohort. METHODS:High-sensitivity cTnT and cTnI were measured in serum fro...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2018.292086
更新日期：2018-11-01 00:00:00
abstract：:Cholinesterase activity in human serum was measured calorimetrically and compared to values obtained with the spectrophotometric method of Rappaport et al. [Clin. Chim. Acta 4, 227 (1959)]. The response of the calorimeter upon mixing serum with acetylcholine corresponded to the cholinesterase activity of the serum, th...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1977-10-01 00:00:00
abstract：:We evaluated the HemoCue beta-Glucose Photometer system for use in our neonatal intensive care unit by assaying 178 heparinized whole-blood samples obtained by heel stick. The required sample size is 5 microL. Plasma glucose was analysed by a glucose oxidase/oxygen electrode methodology. Across the glucose range of 1....
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1993-11-01 00:00:00
abstract：:In this study we determined the prevalence of autoantibodies against casein kinase II (CKII) in patients positive for anti-70K marker antibodies, which is indicative of mixed connective tissue disease. An anti-CKII ELISA was established with the use of bacterially expressed recombinant CKII proteins. Eight out of 52 a...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1993-12-01 00:00:00
abstract：BACKGROUND:Measurements of the ionic current flowing through nanometer-scale pores (nanopores) have been used to analyze single DNA and RNA molecules, with the ultimate goal of achieving ultrafast DNA sequencing. However, attempts at purely electronic measurements have not achieved the signal contrast required for sing...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2007.091231
更新日期：2007-11-01 00:00:00
abstract：:The identification of nicotinamide-N1-oxide as a metabolite in the urine of a schizophrenic patient prompted a study of the relative metabolism of nicotinic acid and nicotinamide in mental patients and healthy volunteers. Metabolites quantified included N1-methyl-2-pyridone-5-carboxamide, N1-methyl-4-pyridone-3-carbox...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1976-11-01 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：:A plasma protein required for the support of ristocetin-induced platelet aggregation was isolated from antihemophilic factor concentrate and radiolabeled with 125I. A double-antibody radioimmunoassay was developed, with use of specific rabbit anti-VIII related antigen serum and goat anti-rabbit globulin. The assay is ...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1977-09-01 00:00:00
abstract：:Under the Clinical Laboratory Improvement Act of 1967 the Health Care Financing Administration's proficiency-testing requirement applies to approximately 12,000 hospital, reference, and large-clinic laboratories in the United States. The Wisconsin State Laboratory of Hygiene is approved by the Health Care Financing Ad...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1992-07-01 00:00:00
