Abstract:
:The precision of estimates of the sensitivity of diagnostic tests is evaluated. "Sensitivity" is defined as the fraction of diseased subjects with test values exceeding the 0.975-fractile of the distribution of control values. An estimate of the sensitivity is subject to sample variation because of variation of both control observations and patient observations. If gaussian distributions are assumed, the 0.95-confidence interval for a sensitivity estimate is up to +/- 0.15 for a sample of 100 controls and 100 patients. For the same sample size, minimum differences of 0.08 to 0.32 of sensitivities of two tests are established as significant with a power of 0.90. For some published diagnostic test evaluations the median sample sizes for controls and patients were 63 and 33, respectively. I show that, to obtain a reasonable precision of sensitivity estimates and a reasonable power when two tests are being compared, the number of samples should in general be considerably larger.
journal_name
Clin Chemjournal_title
Clinical chemistryauthors
Linnet Ksubject
Has Abstractpub_date
1985-04-01 00:00:00pages
574-80issue
4eissn
0009-9147issn
1530-8561journal_volume
31pub_type
杂志文章abstract::Ornithine carbamoyltransferase (EC 2.1.3.3) activity is a sensitive, specific indicator of hepatocellular injury. This paper describes development of an improved automated procedure for measurement of this activity. Triethanolamine-ethylenediaminetetraacetate is used as a buffer, and activity is determined by measurin...
journal_title:Clinical chemistry
pub_type: 杂志文章
doi:
更新日期:1975-05-01 00:00:00
abstract:BACKGROUND:Blockade of the renin-angiotensin system (RAS) represents a main strategy in the therapy of heart failure with reduced ejection fraction (HFrEF), but the role of active renin concentration (ARC) for guiding therapy in the presence of an RAS blockade remains to be established. This study assessed angiotensin ...
journal_title:Clinical chemistry
pub_type: 杂志文章
doi:10.1373/clinchem.2017.278705
更新日期:2018-03-01 00:00:00
abstract::On-line, simultaneous measurement of blood K+, Ca2+, Na+, and pH has been achieved by using a quadruple-function ChemFET (chemical-sensitive field-effect transistor) integrated-circuit sensor. Blood is withdrawn from the subject through an actively heparinized, dual-lumen cannula and passed into a flow-cell containing...
journal_title:Clinical chemistry
pub_type: 杂志文章
doi:
更新日期:1984-01-01 00:00:00
abstract::During direct illumination of a serum bilirubin solution the bilirubin concentration decreased markedly, both as determined by the direct spectrometric method and (even more so) by the diazo method. In contrast, I found the same values for serum bilirubin concentrations as determined by these two methods for serum fro...
journal_title:Clinical chemistry
pub_type: 杂志文章
doi:
更新日期:1977-01-01 00:00:00
abstract::Agarose column chromatography has been used to separate plasma lipoproteins into very-low-density lipoproteins (VLDL), low-density lipoproteins (LDL) and high-density lipoproteins (HDL). Applied to the diagnosis of primary type III hyperlipoproteinemia, the procedure is capable of demonstrating three characteristic an...
journal_title:Clinical chemistry
pub_type: 杂志文章
doi:
更新日期:1975-12-01 00:00:00
abstract::We have studied factors affecting biological variation in total plasma alkaline phosphatase in a population of 32 329 apparently healthy subjects four years old or older. Quantification of the bone and liver isoenzymes after thermal denaturation made it possible to specify the contributions of each isoenzyme to variat...
journal_title:Clinical chemistry
pub_type: 杂志文章
doi:
更新日期:1983-04-01 00:00:00
abstract:BACKGROUND:In this study we demonstrate the technical application of flow cytometry and cell sorting combined with gene-rearrangement clonality profiling to detect and confirm minimal disease in 2 leukemia and 2 lymphoma cases. METHODS:Specimens with low percentages (0.05%-5%) of abnormal lymphoid populations were ide...
journal_title:Clinical chemistry
pub_type: 杂志文章
doi:10.1373/clinchem.2005.061259
更新日期:2006-03-01 00:00:00
abstract::We assayed norepinephrine and epinephrine by utilizing solvent extraction, fluorescence derivatization, and "high-performance" liquid chromatography. A 100-microL aliquot of urine was extracted twice according to Smedes et al. (J Chromatogr 1982;231:25-39) and subsequently incubated with 1,2-diphenylethylenediamine. A...
journal_title:Clinical chemistry
pub_type: 杂志文章
doi:
更新日期:1990-05-01 00:00:00
abstract::We describe the conjoint measurement in urine of the alcoholic catecholamine metabolites 3,4-dihydroxyphenylglycol (DHPG) and 3-methoxy-4-hydroxyphenylglycol (MHPG). The method involves extraction with ethyl acetate and back-extraction into acetic acid (MHPG), followed by adsorption onto alumina (DHPG). The separation...
journal_title:Clinical chemistry
pub_type: 杂志文章
doi:
更新日期:1988-05-01 00:00:00
abstract:BACKGROUND:Measurement of hemoglobin A1c (HbA1c) in the blood is integral to and essential for the treatment of patients with diabetes mellitus. HbA1c reflects the mean blood glucose concentration over the preceding 8 to 12 weeks. Although the clinical value of HbA1c was initially limited by large differences in result...
journal_title:Clinical chemistry
pub_type: 杂志文章,评审
doi:10.1373/clinchem.2018.296962
更新日期:2019-07-01 00:00:00
abstract::In this method for serum and urinary urea determination, the same reagent is used without predilution of urine samples. The method is based on the pH increase resulting from the ammonia released by urease hydrolysis of urea. o-Cresolphthalein complexone is used to monitor the pH change colorimetrically. Urea concentra...
journal_title:Clinical chemistry
pub_type: 杂志文章
doi:
更新日期:1992-05-01 00:00:00
abstract::Of 98 patients' specimens examined for alkaline phosphatase (EC 3.1.3.1) isoenzymes by electrophoresis on cellulose acetate membrane after incubation with neuraminidase, 50 showed only a single liver or bone isoenzyme staining band; in 15 of these, the tissue origin of the fraction could not be accurately identified f...
journal_title:Clinical chemistry
pub_type: 杂志文章
doi:
更新日期:1985-07-01 00:00:00
abstract::We have developed an HPLC method for measuring carbamylated hemoglobin (CarHb), based on the quantification of valine hydantoin formed from the released NH2-terminal carbamyl valine residue after acid hydrolysis of hemoglobin. In uremia, CarHb is produced by nonenzymatic post-translational modification of the terminal...
journal_title:Clinical chemistry
pub_type: 杂志文章
doi:
更新日期:1990-04-01 00:00:00
abstract::It is time-consuming to process and compare the clinical and marker information registered during monitoring of breast cancer patients. To facilitate the assessment, we developed a computer program for interpreting consecutive measurements. The intraindividual biological variation, the analytical precision profile, th...
journal_title:Clinical chemistry
pub_type: 临床试验,杂志文章,随机对照试验
doi:
更新日期:2000-08-01 00:00:00
abstract::We present a unified approach to the use of linear models and matrix least squares with the intention of providing a better understanding of the techniques themselves and of the statistics that arise from these techniques as they are used in clinical chemistry. Emphasis is placed on the importance of appropriate exper...
journal_title:Clinical chemistry
pub_type: 杂志文章
doi:
更新日期:1979-06-01 00:00:00
abstract:BACKGROUND:An assay using a mouse antisialyl Lewis X (sLeX) antibody (CSLEX-1) is used clinically for screening and monitoring patients with breast cancer in Japan. However, the IgM isoform of CSLEX-1 is not preferred for the assay because the bulkiness of IgM generally causes poor accessibility to the antigen. To solv...
journal_title:Clinical chemistry
pub_type: 杂志文章
doi:10.1373/clinchem.2016.260968
更新日期:2016-11-01 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:BACKGROUND:Increased cardiac troponin concentrations in acute coronary syndrome (ACS) identify patients with ongoing cardiomyocyte necrosis who are at increased risk. However, with the use of more precise assays, cardiac troponin increases are commonly noted in other cardiovascular conditions as well. This has generate...
journal_title:Clinical chemistry
pub_type: 杂志文章,评审
doi:10.1373/clinchem.2016.261495
更新日期:2017-01-01 00:00:00
abstract:BACKGROUND:alpha(1)-Antitrypsin is the major plasma serine protease inhibitor. Its deficiency is mainly associated with the alleles PI*S and PI*Z and can lead to obstructive lung disease in adults and to liver cirrhosis during childhood. METHODS:A multiplex PCR method has been established that uses two sets of primers...
journal_title:Clinical chemistry
pub_type: 杂志文章
doi:
更新日期:2000-02-01 00:00:00
abstract::We report the accuracy, imprecision, total analytical errors, and patient misclassification errors for cholesterol measured from capillary whole blood, venous whole blood, and venous plasma samples by five devices used in public cholesterol screening environments: Reflotron, Vision, Ektachem DT-60, QuickRead, and Lipo...
journal_title:Clinical chemistry
pub_type: 杂志文章
doi:
更新日期:1993-02-01 00:00:00
abstract::We compared the performance of an automated assay of creatine kinase MB isoenzyme (CK-MB) mass (Stratus) with that of a CK-MB enzymatic assay routinely used at our institutions. Both of these assays use the same CK-MB-specific monoclonal antibody to immunocapture CK-MB, thus providing a direct means of comparing a mas...
journal_title:Clinical chemistry
pub_type: 杂志文章
doi:
更新日期:1989-10-01 00:00:00
abstract:BACKGROUND:The 2447 A > T pathogenic variation at codon 816 of exon 17 (D816V) in the KIT gene, occurring in systemic mastocytosis (SM), leads to constitutive activation of tyrosine kinase activity and confers resistance to the tyrosine kinase inhibitor imatinib mesylate. Thus detection of this variation in SM patients...
journal_title:Clinical chemistry
pub_type: 杂志文章
doi:10.1373/clinchem.2006.068205
更新日期:2006-12-01 00:00:00
abstract::We modified the ISO-DALT two-dimensional gel electrophoresis system to allow the routine examination of serum specimens from patients with monoclonal gammopathies. This system, MC-Iso 1, is characterized by a broad pH gradient for resolving the basic immunoglobulin heavy and light chains. The increased resolution of b...
journal_title:Clinical chemistry
pub_type: 杂志文章
doi:
更新日期:1982-04-01 00:00:00
abstract::To compare six assays of hyaluronan (hyaluronic acid; HYA) in serum, developed in different laboratories, we analyzed 10 samples from each of three groups: healthy persons, patients with primary biliary cirrhosis, and patients with rheumatoid arthritis. All the assays are based on the use of affinity proteins specific...
journal_title:Clinical chemistry
pub_type: 杂志文章
doi:
更新日期:1992-01-01 00:00:00
abstract::We describe the measurement of human immunoglobulins IgG, IgA, and IgM in diluted sera, with diluted commercial monospecific antisera, with use of a 36-place centrifugal analyzer (RotoChem IIa; American Instrument Co., Silver Spring, MD 20920). The assay involves a two-point kinetic turbidimetric technique. The change...
journal_title:Clinical chemistry
pub_type: 杂志文章
doi:
更新日期:1979-04-01 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:Concerns exist regarding how the 99th percentile upper reference limit (URL) of cardiac troponin (cTn) is determined and whether it should be derived from normal healthy individuals. CONTENT:The 99th percentile URL of cTn is an important criterion to standardize the diagnosis of myocardial infarction (MI) f...
journal_title:Clinical chemistry
pub_type: 杂志文章
doi:10.1093/clinchem/hvaa158
更新日期:2020-09-01 00:00:00
abstract::Ammonia concentrations in plasma may increase because of contamination and deterioration of blood components during specimen handling and storage. Using replicate specimens from healthy volunteers, we studied influences of specimen processing and storage procedures on ammonia measurements made with a self-contained re...
journal_title:Clinical chemistry
pub_type: 杂志文章
doi:
更新日期:1984-06-01 00:00:00
abstract::Four commercial products for urine glucose determination were evaluated and compared with a quantitative hexokinase procedure. We examined precision, sensitivity, and analytical recovery of glucose from glucose-supplemented urine samples and comparison of methods, using patients' samples. Only "Chemstrip uG" (Bio-Dyna...
journal_title:Clinical chemistry
pub_type: 杂志文章
doi:
更新日期:1982-10-01 00:00:00
abstract:BACKGROUND:Formalin-fixed paraffin-embedded (FFPE) tumor material represents a valuable resource for the analysis of RNA-based biomarkers, both in research laboratories and in routine clinical testing. A robust and automated RNA-extraction method with a high sample throughput is required. METHODS:We evaluated extracti...
journal_title:Clinical chemistry
pub_type: 杂志文章
doi:10.1373/clinchem.2008.122572
更新日期:2009-09-01 00:00:00