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PubMed2006

Statistical analyses of correlation between fluconazole MICs for Candida spp. assessed by standard methods set forth by the European Committee on Antimicrobial Susceptibility Testing (E.Dis. 7.1) and CLSI (M27-A2).

The European Committee on Antimicrobial Susceptibility Testing (EUCAST) Subcommittee on Antifungal Susceptibility Testing recently published a standard for determining the susceptibility of fermentative yeasts to antifungals. From the beginning, the EUCAST and its North American counterpart, the CLSI, decided to work together in order to establish common standards. As part of this exercise, the susceptibility of a set of 475 yeast isolates was tested by both standards. The intraclass correlation coefficient and the equations defining the linear regression between both methods were estimated. Both methods produced very similar results, with an intraclass correlation coefficient of 0.954 (0.945 to 0.962), although linear regression analysis shows that the EUCAST standard resulted in slightly lower MICs. There were only eight isolates showing at least four twofold dilution MIC differences between both standards. After 24 h of incubation, the MICs obtained by the CLSI method were equivalent to those obtained by the EUCAST standard. In summary, both methods produce very similar MICs, indicating that methodology does not pose any obstacle to obtaining uniform standards for antifungal susceptibility testing of yeasts.

Antifungal Agents↗

PubMed2004

Use of multiple nucleic acid amplification tests to define the infected-patient "gold standard" in clinical trials of new diagnostic tests for Chlamydia trachomatis infections.

Nucleic acid amplification tests (NAATs) can be used to define the infected-patient "gold standard" for the purpose of designing studies of the performance of Chlamydia trachomatis diagnostic tests. It is unclear how many test results run by different NAATs and what combinations of specimens comprise the best infected-patient gold standard. We approached this question with data from a large study of the performance of a new NAAT. Data were available from three endocervical swabs and a urine specimen collected from each of 1,412 women and tested by three different NAATs. Results from all three assays were used equally in a rotating fashion to define the infected-patient gold standard. Multiple different infected-patient gold standards for estimating swab and urine specimen sensitivity and specificity for one NAAT method were created by varying the number and combinations of swab and urine comparator results with two different NAATs, The effect of changing the infected-patient gold standard definition was determined by constructing receiver-operator-like curves with calculated sensitivities and specificities for each test. The one-positive-of-two-results or two-positive-of-two-results (same or two different assays) infected-patient gold standard definitions produced low sensitivity and low specificity estimates, respectively. If four comparator NAAT results were used, the any-three-positive-of-four-results definition or the at-least-one-specimen-positive-by-each-of-two-comparator-assays definition appeared to provide better combinations of sensitivity and specificity estimates. The any-two-positive-out-of-three-results definition resulted in estimates that were as good as produced with the former two definitions. This analytic approach provides a means of clearly visualizing the effects of changing NAAT-based infected-patient gold standards and should be helpful in designing future studies of new C. trachomatis diagnostic tests.

Cervix Uteri↗

PubMed2005

Discordance between viral loads determined by Roche COBAS AMPLICOR human immunodeficiency virus type 1 monitor (version 1.5) Standard and ultrasensitive assays caused by freezing patient plasma in centrifuged becton-dickinson vacutainer brand plasma preparation tubes.

The Roche COBAS AMPLICOR human immunodeficiency virus type 1 (HIV-1) Monitor (version 1.5) standard and ultrasensitive viral load assays often gave discordant results, with viral loads from the standard assay exceeding those from the ultrasensitive assay by more than 0.5 log(10) for approximately 20% of specimens received. We began studies to determine the extent, magnitude, and reproducibility of the discordance between the assays and to discover and eliminate the cause of this discordance. Until then, we revised our standard operating procedure to include both standard and ultrasensitive testing on all specimens submitted for viral load determinations. Discordant results usually recurred on retesting. They were most prevalent for specimens with ultrasensitive viral loads of <1,000 and rare for specimens with viral loads of >10,000. Often, standard assay results exceeded those of the ultrasensitive assay by 50- to 100-fold. At higher viral loads, the difference between the standard and ultrasensitive assays persisted, but the percent difference was smaller and rarely caused discordance. The proportion of discordant results was significantly higher in specimens from pediatric patients than in specimens from adults. The ultrasensitive viral load determinations generally agreed with the results of the B-DNA (Bayer) viral load assays. If the plasma was transferred from the centrifuged plasma preparation tubes before freezing, standard and ultrasensitive results were concordant with each other and with values determined on plasma from lavender-topped EDTA tubes.

Adolescent↗

PubMed1992

Medical audit in general practice. II: Effects on health of patients with common childhood conditions. North of England Study of Standards and Performance in General Practice.

OBJECTIVE: To estimate the effects of medical audit, particularly setting clinical standards, on patients' health. DESIGN: Before and after study strengthened by a replicated Latin square. SETTING: 62 training general practices in the north of England. PATIENTS: Random sample of 9000 children with any of five conditions--acute cough, acute vomiting, bedwetting, itchy rash, and recurrent wheezy chest--stratified by doctor consulted, condition, and age. INTERVENTIONS: Clinical standard set by each of 10 small groups comprising 84 general practitioner trainers for one randomly selected childhood condition. Each group also experienced a different type of medical audit, randomly selected, for each of the four other study conditions (receiving a clinical standard set by another trainer group, tabulated data comparing clinical performance with that of all other groups, tabulated data from only their own group, and nothing ("control" condition)). MAIN OUTCOME MEASURES: Condition specific, functional, psychological, and educational outcomes; together with parent satisfaction (recorded by home interviews and postal questionnaires). RESULTS: Children consulting trainers for recurrent wheezy chest after those doctors had set a standard for that condition improved both in drug compliance (79% (n = 33) before standard setting v 93% (30) after) and mean number of days of breathlessness (3.8 (SE 1.0) before v 1.7 (0.6) after) and wheeziness (4.7 (0.9) before v 1.8 (0.6) after), compared with those consulting doctors who had not (compliance 74% (144) before v 72% (146) after; breathlessness 2.4 (0.4) before v 2.3 (0.3) after; wheeziness 3.0 (0.4) before v 2.7 (0.4) after). There were no other significant effects of standard setting or audit on patients' health. CONCLUSION: Setting clinical standards improved drug compliance and respiratory function in children with recurrent wheezy chest.

Child↗

PubMedDate not supplied

Standards for medical identifiers, codes, and messages needed to create an efficient computer-stored medical record. American Medical Informatics Association.

A major obstacle to establishing a computer-stored medical record is the lack of "standards" that would permit government, care providers, insurance companies, and medical computer system developers to share patient data easily. In this position paper, the Board of Directors of the American Medical Informatics Association recommends specific approaches to standardization in the areas of patient, provider, and site of care identifiers; computerized health care message exchange; medical record content and structure, and medical codes and terminologies. The key concept developed in this position paper is that developers and users of computer-stored medical records must embrace existing and tested approaches, despite their imperfections, to progress quickly. This approach to standardization is being coordinated with the American National Standards Institute's Health Informatics Standards Planning Panel. The development of standards is a long-term process involving continued refinement. The proposed standards are an important step toward the goal of better and more efficient health care.

Association↗

PubMed2004

Evaluation of swab transport systems against a published standard.

BACKGROUND: Before the publication of the M40-A standard by the United States National Committee for Clinical Laboratory Standards (NCCLS), no quality control data for swab transport systems (STSs) had been available. AIMS: To compare three commercially available STSs against the published standard to ascertain bacterial survival after a set holding time. METHOD: Charcoal and non-charcoal containing swabs were inoculated with standard volumes and numbers of a range of bacteria commonly isolated from clinical material. Bacterial counts were taken at time zero, six, 24, and 48 hours, with the results being compared against the NCCLS standard. RESULTS: The standard clearly differentiated between the three STSs tested, with one product being superior to the other two products in providing better survival. CONCLUSION: The standard now provides manufacturers and users of STSs with meaningful data to provide, purchase, and compare an STS for routine clinical use.

Bacteria↗

PubMed1994

Living standards and mortality in the European Community.

OBJECTIVE: The association between living standards and mortality in the European Community (EC) was investigated using regional level data from all EC member countries. DATA AND METHODS: Data covering the 1980s were extracted from various publications. Data on "all cause" mortality (standardised mortality ratios, both sexes, all ages), living standards (gross domestic product, car access, unemployment rates), and some potential confounders (population density, agricultural employment, industrial employment, country) were available for 133 regions. Multiple regression analysis was used for each living standard variable, taking lnSMR as the dependent variable. RESULTS: It is only after taking into account potential confounders that higher living standards are associated with lower mortality. Unemployment rates have the strongest association--each additional percentage in unemployment in the regional population is associated with an increase in mortality by 0.81%. There is important variation between countries in the living standards--mortality relationship. The latter ranges from relatively strong in the UK to absent in Italy. DISCUSSION: The results of this study show that there is an association between living standards and mortality at the regional level in the EC, but that this association comes to light only after controlling for confounding variables. It seems that the mortality increasing effects of urbanisation and industrialization have obscured the mortality lowering effects of high living standards. In addition, factors specific to countries (such as dietary habits) act as confounders. The latter finding is interpreted in the light of differences between countries in the way in which they have gone through the "epidemiologic translation" from infectious diseases to the "western" diseases that currently dominate the mortality pattern.

Adolescent↗

PubMed1998

Material standard of living, social class, and the prevalence of the common mental disorders in Great Britain.

STUDY OBJECTIVE: To test the hypothesis that poor material standard of living is independently associated with the prevalence of the common mental disorders after adjusting for occupational social class, and to estimate the population impact of poor material standard of living on the prevalence of these disorders. DESIGN: Cross sectional survey. Prevalence of the common mental disorders was assessed using the General Health Questionnaire, a self administered measure of psychiatric morbidity. PARTICIPANTS: 9064 adults aged 16-75 living in private households in England, Wales, and Scotland. MAIN RESULTS: The common mental disorders were significantly associated with poor material standard of living, including low household income (OR 1.24, 95% CI 1.00, 1.54) and not saving from income (OR 1.29, 95% CI 1.15, 1.45), after adjusting for occupational social class and other potential confounders. An independent association was also found with occupational social class of the head of household among women, but not men, after adjusting for material standard of living. The adjusted population attributable fraction for poor material standard of living (using a five item index) was 24.0%. CONCLUSIONS: Like mortality and physical morbidity, common mental disorders are associated with a poor material standard of living, independent of occupational social class. These findings support the view that recent widening of inequalities in material standards of living in the United Kingdom pose a substantial threat to health.

Adolescent↗

PubMed1992

Introduction to the ACR-NEMA DICOM standard.

In 1982, the American College of Radiology (ACR) and the National Electrical Manufacturers Association (NEMA) formed a committee to develop standards for the interconnection of digital imaging devices. Version 1.0 of the standard, published in 1985, specifies a hardware interface supporting point-to-point (not network) image transmission, a data dictionary (a set of rules for encoding information), and a set of commands to initiate transactions. Version 2.0, published in 1988, also addresses point-to-point image transmission and provides semantic rules by which messages (streams of bits representing information in transit from one device to another) are organized. Version 3.0, also referred to as DICOM (Digital Imaging and Communications in Medicine), will be finalized in 1992. The DICOM standard encourages open systems interconnection of imaging equipment over standard networks, while maintaining compatibility with earlier point-to-point connection standards. The DICOM standard conforms fully with the International Standards Organization reference model for network communications (ISORM), addresses the issue of conformance, and incorporates the concept of object-oriented design.

Computer Communication Networks↗

PubMed2005

Association between compliance with methodological standards of diagnostic research and reported test accuracy: meta-analysis of focused assessment of US for trauma.

PURPOSE: To study whether compliance with methodological standards affected the reported accuracy of screening ultrasonography (US) for trauma. MATERIALS AND METHODS: Meta-analysis was conducted of prospective investigations in which US was compared with any diagnostic reference test in patients with suspected abdominal injury. Reports were retrieved from electronic databases without language restrictions; added information was gained with manual search. Two reviewers independently assessed methodological rigor by using 27 items contained in the Standards for Reporting of Diagnostic Accuracy (STARD) checklist and the Quality Assessment of Studies of Diagnostic Accuracy included in Systematic Reviews (QUADAS) instrument. Inconsistencies were resolved by means of consensus. Summary receiver operating characteristics and random-effects meta-regression were used to model the effect of methodological standards and other study features on US accuracy. RESULTS: A total of 62 trials, which included a total of 18,167 participants, were eligible for meta-analysis. The average proportion of men or boys was 71.7%, the mean age was 30.6 years +/- 10.8 (standard deviation), and the mean injury severity score was 16.7 +/- 8.3. The prevalence of abdominal trauma was 25.1% (95% confidence interval [CI]: 21.1%, 29.1%). Pooled overall sensitivity and specificity of US were 78.9% (95% CI: 74.9%, 82.9%) and 99.2% (95% CI: 99.0%, 99.4%), respectively. Varying end points (hemoperitoneum or organ damage) did not change these results. US accuracy was much lower in children (sensitivity, 57.9%; specificity, 94.3%). Strong heterogeneity was observed in sensitivity, whereas specificity remained constant across trials. There was evidence of publication bias. Initial interobserver agreement with methodological standards ranged from poor (kappa = 0.03, independent verification of US findings) to perfect (kappa = 1.00, sufficiently short interval between US and reference test). By consensus, studies fulfilled a median of 13 methodological criteria (range, five to 20 criteria). In investigations that lacked individual methodological standards, researchers overestimated pooled sensitivity, with predicted differences of 9%-18%. The use of a single reference test, specification of the number of excluded patients, and calculation of CIs independently contributed to predicted sensitivity in a multivariate model. In 16 investigations (1309 subjects), a single reference test was used, which provided a combined sensitivity of 66.0% (95% CI: 56.2%, 75.8%). CONCLUSION: Bias-adjusted sensitivity of screening US for trauma is low. Adherence to methodological standards included in appraisal instruments like STARD and QUADAS is crucial to obtain valid estimates of test accuracy.

Abdominal Injuries↗

PubMed2000

Standardized abnormal interpretation and cancer detection ratios to assess reading volume and reader performance in a breast screening program.

PURPOSE: To determine the relationship between annual screening volume and radiologist performance in the Screening Mammography Program of British Columbia, Canada. MATERIALS AND METHODS: Standardized abnormal interpretation ratios and standardized cancer detection ratios were constructed for 35 readers with at least 3 years of experience with the Screening Mammography Program of British Columbia. The ratios were used to compare individual reader performance with the mean program performance after adjustment for the age and screening history (first versus subsequent screening examinations) of the women who underwent screening. RESULTS: The mean standardized abnormal interpretation ratio was better for readers of 2,000-2,999 (n = 8) and 3,000-3,999 (n = 9) screening mammograms per year than for those of less than 2,000 (n = 9) and 4, 000-5,199 (n = 9) screening mammograms per year. Differences in the mean standardized abnormal interpretation ratios were significant (P <.05) between the readers of less than 2,000 and of 2,000-2,999 screening mammograms per year, between readers of less than 2,000 and of 3,000-3,999 screening mammograms per year and between readers of 3,000-3,999 and of 4,000-5,199 screening mammograms per year. The mean standardized cancer detection ratio improved gradually with increasing annual volume, but the differences between groups were not statistically significant. Five of the eight readers of 2,000-2, 999 mammograms were reading 2,475 or more screening mammograms per year. CONCLUSION: Standardized abnormal interpretation ratios and standardized cancer detection ratios provide a method of comparing two important performance measures in a screening program. A minimum of 2,500 interpretations per year is associated with lower abnormal interpretation rates and average or better cancer detection rates.

Adult↗

PubMed2006

Prognostic value of adaptive textural features--the effect of standardizing nuclear first-order gray level statistics and mixing information from nuclei having different area.

BACKGROUND: Nuclear texture analysis is a useful method to obtain quantitative information for use in prognosis of cancer. The first-order gray level statistics of a digitized light microscopic nuclear image may be influenced by variations in the image input conditions. Therefore, we have previously standardized the nuclear gray level mean value and standard deviation. However, there is a clear relation between nuclear DNA content, area, first-order statistics, and texture. For nuclei with approximately the same DNA content, the mean gray level increases with an increasing nuclear area. The aims of the present methodical work were to study: (1) whether the prognostic value of adaptive textural features varies with nuclear area, and (2) the effect of standardizing nuclear first-order statistics. METHODS: Nuclei from 134 cases of ovarian cancer were grouped into intervals according to nuclear area. Adaptive features were extracted from two different image sets, i.e., standardized and non-standardized nuclear images. RESULTS: The prognostic value of adaptive textural features varied strongly with nuclear area. A standardization of the first-order statistics significantly reduced this prognostic information. Several single features discriminated the two classes of cancer with a correct classification rate of 70%. CONCLUSION: Nuclei having an area between 2000-4999 pixels contained most of the class distance information between the good and poor prognosis classes of cancer. By considering the relation between nuclear area and texture, we avoided a loss of information caused by standardizing the first-order statistics and mixing data from cells having different nuclear area.

Algorithms↗

PubMed1993

Combination of standard cytology and immunocytology with BL2-10D1 monoclonal antibody for monitoring-treated bladder cancer patients.

Monoclonal antibody BL2-10D1 directed against a tumor-associated antigen of bladder carcinoma was used for monitoring 11 intravesically treated patients. Thirty-three bladder washout specimens were used for standard cytology and immunological staining. Prior to treatment, 9 of 11 cytologic specimens examined with standard cytology were found to be positive. Using BL2-10D1 alone, only 6 were positive but 1 patient negative with standard cytology was positive with the antibody and corresponded to a positive histological control. Thus, before treatment, an increase in positive rate was observed using the combination of the 2 methods from 82 to 91%. At the end of treatment, 9 washout specimens remained positive with standard cytology, whereas 1 case negative in standard cytology was positive in immunocytology. Thus, the positive rate increased from 82 to 91%. One month after the end of treatment, of 11 washout specimens tested, 3 false-negative standard cytologies and 4 false-negative immunocytologies were shown. However, used in combination, the two methods lead to an increase in positive rate from 67 to 89%. In view of these results, BL2-10D1 may be considered as a useful reagent in combination with the standard cytology for the confirmation of the presence of tumor cells before and after immunotherapy.

Antibodies, Monoclonal↗

PubMed1991

Reliability of a Standardized Mini-Mental State Examination compared with the traditional Mini-Mental State Examination.

OBJECTIVE: The objective of this study was to compare the reliability of the Mini-Mental State Examination with that of a new Standardized Mini-Mental State Examination, which has expanded guidelines for administration and scoring. METHOD: The subjects were 32 stable elderly residents of a nursing home and 16 elderly residents of a chronic care hospital unit. Six raters administered the Folstein Mini-Mental State to 22 of these stable elderly subjects, and five raters administered the standardized version to 26 of these subjects. Each subject was tested on three different occasions 1 week apart. Each rater tested 4-6 subjects at the first and third weeks and 4-6 different subjects at the second week. The analytic technique used was one-way analysis of variance to estimate the interrater variance and the intrarater variance. RESULTS: The intrarater variance on all occasions was reduced by 86% and the interrater variance was reduced by 76% when the Standardized Mini-Mental State was used; the reductions in variance were significant (p less than 0.003). The intraclass correlation for the Mini-Mental State was 0.69; for the standardized version it was 0.90. It took less time to administer the Standardized Mini-Mental State than the Mini-Mental State. CONCLUSIONS: The Standardized Mini-Mental State had better reliability than the Mini-Mental State in this study group. Although the improved reliability of the Standardized Mini-Mental State was achieved by reducing measurement noise, this advantage would likely occur in a broad spectrum of patients.

Aged↗

PubMed1986

Implementing the ANSI Z 136.3 laser safety standard in the medical environment.

The American National Standards Institute (ANSI) is an organization comprising several committees of expert volunteers who have traditionally determined the industry consensus standards in various fields. The existing federal legislation and the suggested state laser-safety regulation are based on the 1980 ANSI Standard, "For the Safe Use of Lasers." It was quickly recognized that the safety needs of the industrial and medical environments differed sufficiently to prompt the American National Standards Institute to form a committee to write a new set of standards for "Laser Safety in the Health Care Environment" (ANSI Z 136.3). This standard will apply not only to hospitals but also to offices, clinics, and anywhere else that the laser is used for medical purposes. This paper will outline this important laser-safety standard and describe in detail how best to implement it in the environment in which the otolaryngologist--head and neck surgeon practices.

Equipment Safety↗

PubMed1991

Development of clinical practice standards for nurses.

Nursing, with leadership from the American Nurses Association (ANA), has a long-standing commitment to the development of standards. The first nursing practice standards were published in 1973. Since that time, both the ANA and specialty nursing organizations have developed standards. However, the proliferation of standards, reflecting a wide divergence of intent, format, and scope, has limited their usefulness. In 1989, the ANA appointed a Task Force (now a Committee) to address this issue. The Committee, working with representatives of the specialty nursing organizations, has developed a framework for development of both nursing practice standards and guidelines. Standards and guidelines are defined and differentiated. The relationship of standard and guidelines development to the federal government's effectiveness initiative is discussed.

American Nurses' Association↗

PubMed1997

Implementing quality: a study of the adoption and implementation of quality standards in the contracting process in a general practitioner multifund.

The increase in managerialism in the 1980s and the 1990 NHS reforms have had major implications for the regulation of providers. Purchasers of health care in the UK are now expected to specify three factors in their contracts: volume, cost and quality. This paper focuses on one of these: i.e. the quality standards purchasers now include within their health service contracts. The case study is of a general practitioner multifund and the analysis focuses on how quality standards are derived and adopted in outpatient contracts. The data were derived from in-depth face-to-face interviews with the key participants in the contracting process. The evidence shows that the standards were derived and adopted with very little participation from the providers. The impact of the quality standards on hospitals consultants' behaviour was negligible, there was very little monitoring of the standards by the multifund, and providers accepted standards which they knew they could not meet. It is concluded that this non-participatory method of developing the quality standards is likely to mean that their impact on service delivery will be limited.

Ambulatory Care↗

PubMedDate not supplied

A simulation study on the accuracy of position and effect estimates of linked QTL and their asymptotic standard deviations using multiple interval mapping in an F(2) scheme.

Approaches like multiple interval mapping using a multiple-QTL model for simultaneously mapping QTL can aid the identification of multiple QTL, improve the precision of estimating QTL positions and effects, and are able to identify patterns and individual elements of QTL epistasis. Because of the statistical problems in analytically deriving the standard errors and the distributional form of the estimates and because the use of resampling techniques is not feasible for several linked QTL, there is the need to perform large-scale simulation studies in order to evaluate the accuracy of multiple interval mapping for linked QTL and to assess confidence intervals based on the standard statistical theory. From our simulation study it can be concluded that in comparison with a monogenetic background a reliable and accurate estimation of QTL positions and QTL effects of multiple QTL in a linkage group requires much more information from the data. The reduction of the marker interval size from 10 cM to 5 cM led to a higher power in QTL detection and to a remarkable improvement of the QTL position as well as the QTL effect estimates. This is different from the findings for (single) interval mapping. The empirical standard deviations of the genetic effect estimates were generally large and they were the largest for the epistatic effects. These of the dominance effects were larger than those of the additive effects. The asymptotic standard deviation of the position estimates was not a good criterion for the accuracy of the position estimates and confidence intervals based on the standard statistical theory had a clearly smaller empirical coverage probability as compared to the nominal probability. Furthermore the asymptotic standard deviation of the additive, dominance and epistatic effects did not reflect the empirical standard deviations of the estimates very well, when the relative QTL variance was smaller/equal to 0.5. The implications of the above findings are discussed.

Animals↗