Abstract：
BACKGROUND:Commercial immunoassays for testosterone (Te) may give inaccurate results for samples from women and children, leading to misdiagnosis and inappropriate treatment. We developed a sensitive and specific tandem mass spectrometric assay for measurement of Te at the concentrations encountered in women and children. METHODS:Te was extracted with methyl tert-butyl ether from 100 microL of serum or plasma, derivatized to form an oxime, and reextracted by solid-phase extraction. Instrumental analysis was performed on an API 4000 HPLC tandem mass spectrometer in the multiple-reaction monitoring (MRM) mode. The MRM transitions (m/z) were 304-->124 and 304-->112 for Te and 307-->124 and 307-->112 for d3-Te. RESULTS:Within- and between-run CVs were <12% and 7.9%, respectively. The limit of quantification was 0.0346 nmol/L (1 ng/dL). Reference intervals for sex hormone-binding globulin and total, free, and bioavailable Te were established for children of Tanner stages 1 through 5 and adult males and females. CONCLUSIONS:The sensitivity and specificity of the method are adequate for analysis of Te in samples from women and children. The method requires small sample volumes, has adequate precision, and is not subject to interferences.
journal_name
Clin Chemjournal_title
Clinical chemistryauthors
Kushnir MM,Rockwood AL,Roberts WL,Pattison EG,Bunker AM,Fitzgerald RL,Meikle AWdoi
10.1373/clinchem.2005.052167subject
Has Abstractpub_date
2006-01-01 00:00:00pages
120-8issue
1eissn
0009-9147issn
1530-8561pii
clinchem.2005.052167journal_volume
52pub_type
杂志文章abstract：:The metabolism of the synthetic substrate 7-ethoxyresorufin is a selective measure of the activity of cytochrome P-448 monooxygenase, the subset of cytochrome P-450-mediated enzymes preferentially induced by polycyclic aromatic hydrocarbons and related compounds. 7-Ethoxycoumarin metabolism, on the other hand, reflect...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1981-09-01 00:00:00
abstract：:In the Prospective Cardiovascular Münster (PROCAM) study, serum lipoprotein(a) [Lp(a)] and its relationship to pro- and anticoagulatory as well as fibrinolytic indices were determined in a large group of employees: 864 men (m) and 373 women (f), ages 16-65 years. Univariate statistical analysis showed Lp(a) concentrat...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1991-11-01 00:00:00
abstract：:Intra- and interindividual components of biological variation have been determined for total thyroxin (TT4), free thyroxin (FT4), total triiodothyronine (TT3), free triiodothyronine (FT3), and thyrotropin (TSH). Calculated analytical goals (CV, %) for the precision required for optimal patient care are: TT4 less than ...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1986-06-01 00:00:00
abstract：:A profile (chromatographic pattern) of the neutral and acidic metabolites present in cerebrospinal fluid from newborns and infants was obtained by gas-liquid chromatography. The metabolites are those extracted with ethyl acetate and diethyl ether. They are converted to trimethylsilyl ether derivatives, and chromatogra...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1976-05-01 00:00:00
abstract：:To evaluate a theoretical model for calculating free thyroid hormones, based on the law of mass action, we compared values for both calculated and measured free thyroxin and free triiodothyronine in a group of normal subjects. To determine whether the concentrations of circulating free hormones were also predictable f...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1982-06-01 00:00:00
abstract：:We describe an improved separation of the isoenzymes of aspartate aminotransferase (EC 2.6.1.1), based on ion-exchange chromatography. Involving the "Fast Protein Liquid Chromatography" system (Pharmacia) with a MonoQ column, this rapid, reproducible method for quantifying the mitochondrial enzyme shows good resolutio...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1990-02-01 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
abstract：:We have developed an interactive statistical quality-control system for the small- to medium-sized radioimmunoassay laboratory, which can be used in a programmable desk-top calculator instead of the medium- or large-scale computer systems usually required. The design of this quality-control system is modeled after the...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1978-07-01 00:00:00
abstract：:We describe a method for measuring apolipoprotein (apo) C distribution between apo B-containing lipoprotein (apo B-LP) and non-apo B-LP. The procedure requires the precipitation of apo B-LP, the redissolution of the pellet, and the quantification of C peptides in the redissolved pellet. The ratio of apo C in non-apo B...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1994-02-01 00:00:00
abstract：:We examined the changes in sensitivity and specificity that would occur with alterations in the sample-collection schedule and (or) cutoff criterion for the increase in hydrogen concentration in breath after administration of doses of lactose in the dietary range. In a breath-analysis test to classify individuals as l...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1983-03-01 00:00:00
abstract：BACKGROUND:To allow multianalyte binding assays, we have developed a novel polystyrene microtiter plate containing 24 main wells, each divided into 7 subwells. We explored its clinical potential by developing a PCR-chemiluminescent immunoassay (PCR-CLEIA) for simultaneous detection and typing of seven high oncogenic ri...
journal_title：Clinical chemistry
pub_type： 临床试验,杂志文章
doi：
更新日期：2002-10-01 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：BACKGROUND:24,25-Dihydroxyvitamin D [24,25(OH)2D] in serum may be both a nuisance and nutritionally valuable. METHODS:We investigated the impact of 24,25(OH)2D3 on the performance of commercially available immunoassays for serum total 25-hydroxyvitamin D [25(OH)D] using (a) serum from a nationally representative sampl...
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:The thiopurine S:-methyltransferase (TPMT) genetic polymorphism has a significant clinical impact on the toxicity of thiopurine drugs, which are used in the treatment of leukemia and as immunosuppressants. To date, 10 mutant alleles are known that are associated with intermediate or low TPMT activity. To fac...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：2001-03-01 00:00:00
abstract：:An oligonucleotide "melting" procedure was developed whereby we can monitor for a sequence heterogeneity in the gene for apolipoprotein E production. Two oligonucleotides were synthesized, one recognizing the common epsilon 3 allele but not the common epsilon 2 allele, the other recognizing the epsilon 2 allele but no...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1986-07-01 00:00:00
abstract：BACKGROUND:Increased concentrations of cell-free DNA have been found in several disorders and have been interpreted as evidence of increased rates of cell death or turnover. Evidence from in vitro and animal experiments suggests that DNA may play a role in the pathogenesis of rheumatoid arthritis (RA). METHODS:We meas...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2006.084509
更新日期：2007-09-01 00:00:00
abstract：BACKGROUND:Cystic fibrosis is a life-threatening genetic disorder that has been associated with mutations in the CFTR [cystic fibrosis transmembrane conductance regulator (ATP-binding cassette sub-family C, member 7)] gene. Hundreds of CFTR mutations have been detected to date. Current CFTR genotyping assays target a s...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2013.206466
更新日期：2013-10-01 00:00:00
abstract：:We developed a solid-phase two-site immunoenzymometric assay (IEMA) of the estrogen-induced 52-kDa cathepsin D (EC 3.4.23.5) and its processed forms (48-kDa and 34-kDa proteins) in cytosols of breast cancer tissues, using two monoclonal antibodies directed against two different epitopes of these antigens. The first an...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1989-01-01 00:00:00
abstract：BACKGROUND:Because reference values for vitamin B(12) concentrations and vitamin B(12)-binding capacities for pregnant women have not been established, the reference values for nonpregnant women are often applied to assess vitamin B(12) status. The aim of the present study was to describe ranges of biochemical indices ...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：2002-06-01 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 have devloped an enzyme-linked immunosorbent assay for determining choriomammotropin (human placental lactogen) in serum. Unlabeled hormone competes with choriomammotropin-beta-galactosidase conjugate for antibody bound to polystyrene tubes. The entire assay can be performed in 2.5 h with good precision. The coeffi...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1979-02-01 00:00:00
abstract：:The measurement of glycohemoglobin (GHb) by boronate affinity chromatography is useful in monitoring long-term glucose control in diabetic subjects. The inherent disadvantage of this method is the hands-on time required because the hemoglobin fractions are separated on individual disposable columns. To overcome this d...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1993-01-01 00:00:00
abstract：:To study the effect of fatty acid chain saturation on the fluorescence polarization assay as a measure of fetal lung maturity, we used purified phospholipids isolated from human amniotic fluid and various commercial phospholipids. We found that the fluorescence polarization value decreased as the concentration of unsa...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1986-03-01 00:00:00
abstract：BACKGROUND:The short half-life of the alpha-class glutathione S-transferases (GSTAs) in plasma combined with their even distribution throughout the liver lobule suggests that they may be useful complements to the more traditionally used liver markers. However, the currently available assays for measuring GSTAs in biolo...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：2001-05-01 00:00:00
abstract：BACKGROUND:Associations between dairy intake and body composition and cardiometabolic traits have been inconsistently observed in epidemiological studies, and the causal relationship remains ill-defined. METHODS:We performed Mendelian randomization analysis using an established genetic variant located upstream of the ...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2018.300335
更新日期：2019-06-01 00:00:00
abstract：BACKGROUND:The time required for bloodstream pathogen detection, identification (ID), and antimicrobial susceptibility testing (AST) does not satisfy the acute needs of disease management. Conventional methods take up to 3 days for ID and AST. Molecular diagnostics have reduced times for ID, but their promise to suppla...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2018.290189
更新日期：2018-10-01 00:00:00
abstract：:The main developments in the "ligand assay" field in which I have been involved are traced. These include the original development of "first generation" competitive assays relying on radiolabeled analyte markers; the development of the first "second generation", noncompetitive (ultrasensitive) methods, which rely on t...
journal_title：Clinical chemistry
pub_type： 历史文章,杂志文章
doi：
更新日期：1998-09-01 00:00:00
abstract：BACKGROUND:Hyperlipidemia associated with the protease inhibitor (PI) component of highly active antiretrovial treatment can lead to accelerated atherosclerosis. The apolipoprotein A-V (APOA5) gene, which affects VLDL production and lipolysis, may play a role in PI-induced hyperlipidemia, particularly in individuals wi...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2006.069583
更新日期：2006-10-01 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：:Applying the principles of chemometrics can lead to development of a powerful, simple, comprehensive system for characterizing measurement reliability of analytical processes. The system described here consists of a format for specifications, definitions, and decision rules for evaluating and comparing analytical proc...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1988-12-01 00:00:00
