Appropriate laboratory testing in rheumatic diseases

Single-tooth implants were used to replace congenitally absent maxillary lateral incisors in a 17-year-old patient. The inclination of the alveolar process caused a severe discrepancy between the axes of the planned implant and the crown. To avoid the need for a labial screw opening in the crown or labial overcontouring, a CeraOne abutment of the Br?nemark system was modified by selective grinding in the dental laboratory. Individual all-ceramic crowns were fabricated with the Celay In-Ceram system.     

The microbiological profile of nosocomial infection in a respiratory intensive care unit

In 1987, in the Respiratory Intensive Care Unit of Santa Maria Hospital we developed a nosocomial surveillance program with specially created software that provides knowledge of NI in the ICU at any moment. The information gathered along the time is particularly useful in the correlation of the risk factors, the most frequent microorganisms and in the institution of empiric antibiotic therapy. Out of 2528 patients admitted in our ICU for the last 6 years (87/92), 10% had bacteriologically identified NI. Almost (93%) of them had occurred in mechanically ventilated patients, which corresponds to 20.7% NI in those patients. The gram-negative appeared in 63.37%, with the predominance of Enterobacteriaceae. From the gram-positives the most frequent were Staphylococcus spp. Their meticiline resistance was worrisome. NI patients had significantly higher severity and therapeutic intervention scores. Mechanical ventilation period was 4 fold higher and mortality 2.5 times higher in the patients with this complication.     

A quality control program for the radioimmunoassay laboratory

The major problems in applying quality control to radioimmunoassay measurements are (a) nonlinearity of the dose-response curve, and (b) nonuniformity of the residual variance. A logit-log transformation of the dose-response variables combined with an iterative weighted regression analysis appears to overcome most of the difficulties. This technic is particularly helpful when applied to substandard runs where extraneous standard points tend to distort assay results. The authors describe a quality control program that involves recording control values on calendar and histogram formats, monitoring assay variables by charting, and comparing the computer-calculated slope with the graphic plot to reveal "outliers." This program is useful in guiding technologists to locate possible causes for "out-of-limits" runs.     

Evaluation and control of the microbiological quality of hands in foodhandlers

Microbiological analyses of workers' hands were made for the common indicators, including aerobic mesophilic plate counts (APC), as well as the common food pathogens. Opportunities were observed for cross-contamination of roast beef by workers' hands during slicing operations. Workers' hands showed APC counts of up to 10(7) CFU/hand and the presence of S. aureus and C. perfringens. Salmonella spp were not isolated from hands. These results show that handling of these foods by such workers would be a risk in transmitting pathogenic microorganisms to the foods and is apparent that it is necessary for these workers to take care of personal hygiene. Decimal reductions obtained in the microbiological counts after washing and antisepsis of workers' hands were at 2,6 logs cycles and still demonstrated the importance of this practice in food services by the fact that pathogens such as S. aureus and C. perfringens were inhibited or killed.     

疾病预防控制系统微生物实验室内部质量控制

疾病预防卫生微生物检测工作包括病原微生物学检验和卫生学检验,在近几年中,SARS(学名非典)、猪链以及2009年的甲型H1N1流感流等传染性疾病的流行使微生物检验在感染性疾病及相关疾病的预防、诊断治疗中起着重要作用,使我们要不断提高微生物的检验水平.为了保证检验结果的准确性和精确性,我们在平时的工作中要注意开展质量控制.所谓质量控制,广义上是为达到质量所采取的作业技术和活动,其目的在于监视过程并排除质量环的所有阶段中导致不满意的原因.随着人们对质量认识的不断深入,实验室质量控制已不局限于对实验过程的监测,还包括人员培训,采集和运送样本的正确方法,正确选择实验室质控物和确定质量控制标准及评价和管理等.     

均值-极差质量控制图在实验室检测质量控制中的应用

介绍了均值-极差质量控制图在实验室检测控制中的应用。通过绘制直读光谱仪测定20#钢材中碳含量的质量控制图,从图中找出潜在的对检测结果有影响的因素,并加以限制,从而有效预防质量检测事故的发生,是一种“预防为主”的检测质量控制管理手段。     

标准样品在实验室质量控制中的作用

通过使用标准样品对人员、不同原理的分析方法以及仪器进行质量控制论述,论证了标准样品在实验室质量控制中的作用。     

Appropriate use of the intrauterine device

The intrauterine device, a common form of birth control in the early 1970s, is now avoided by American physicians and women because of concern about complications. This concern is largely the result of the problems reported with use of an intrauterine device that is no longer manufactured. More recent intrauterine devices have an improved design, and reevaluation has shown them to be a safe, efficacious and cost-effective form of birth control. Careful patient selection and preinsertion counseling are crucial to success with the device. Recent studies conclude that the intrauterine device poses no increased risk of pelvic inflammatory disease or infertility when used by appropriately selected patients.     

Class restriction of cephalosporin use to control total cephalosporin resistance in nosocomial Klebsiella

CONTEXT: Resistance to most or all cephalosporin antibiotics in Klebsiella species has developed in many European and North American hospitals during the past 2 decades. OBJECTIVE: To determine if restriction of use of the cephalosporin class of antibiotics would reduce the incidence of patient infection or colonization by cephalosporin-resistant Klebsiella. DESIGN: A before-after comparative 2-year trial. SETTING: A 500-bed, university-affiliated community hospital in Queens, NY. PATIENTS: All adult medical and surgical hospital inpatients. INTERVENTION: A new antibiotic guideline excluded the use of cephalosporins except for pediatric infection, single-dose surgical prophylaxis, acute bacterial meningitis, spontaneous bacterial peritonitis, and outpatient gonococcal infection. All other cephalosporin use required prior approval by the infectious disease section. MAIN OUTCOME MEASURE: Incidence of patient infection or colonization by ceftazidime-resistant Klebsiella during 1995 (control period) compared with 1996 (intervention period). RESULTS: An 80.1% reduction in hospital-wide cephalosporin use occurred in 1996 compared with 1995. This was accompanied by a 44.0% reduction in the incidence of ceftazidime-resistant Klebsiella infection and colonization throughout the medical center (P<.01), a 70.9% reduction within all intensive care units (P<.001), and an 87.5% reduction within the surgical intensive care unit (P<.001). A concomitant 68.7% increase in the incidence of imipenem-resistant Pseudomonas aeruginosa occurred throughout the medical center (P<.01). All such isolates except one were susceptible to other antibiotics. CONCLUSION: Extensive cephalosporin class restriction significantly reduced nosocomial, plasmid-mediated, cephalosporin-resistant Klebsiella infection and colonization. This occurred at the price of increased imipenem resistance in P aeruginosa, which remained susceptible to other agents. Thus, an overall reduction in multiply-resistant pathogens was achieved within 1 year.     

Proposed guidelines for the internal quality control of analytical results in the medical laboratory

The factors involved in analytical quality relate to definition of quality, creation of quality, and control of quality, and errors arise from external and internal sources as well as from permanent and variable factors. Further, the two main types of error are classified as systematic and random errors. Internal quality control (IQC) systems can only operate on the variable factors which are related to batch-to-batch variations (external factors) and to the performance in the laboratory (internal factors). In creating an adequate internal control system, several problems are faced: (i) quality of control materials, (ii) types and frequency of possible errors, (iii) number and types of control materials, (iv) number of replicates of the control, (v) probability of error detection, (vi) probability of false rejection, (vii) consequences of reject signals, (viii) trouble-shooting systems, and (ix) prevention of errors among many other conditions. Gaussian distributions of control results are assumed and the statistical control rules are evaluated in relation to probability of false rejections, Pfr, and probability of error detection, Ped, for the different rules. Combinations of low Pfr and high Ped are obtained by combining results from e.g. four measurements of the same control sample by use of mean and range rules. Further, it is not possible to establish a common control system which can be used for all quantities and analytical procedures; on the contrary, each procedure should have its particular efficient IQC system. These aspects are discussed and a number of guidelines for statistical control rules and problem related internal quality control are presented.     

Routine microbiological testing in sudden and unexpected infant death

We reviewed 187 depth recorded seizures in 33 patients with non-lesional temporal lobe complex partial seizures. All patients had a minimum of 1 year follow-up following temporal lobectomy. We classified seizure onset pattern as rhythmic activity, attenuation, or repetitive spikes or spike wave complexes. The most common pattern of seizure onset was rhythmic activity and the next most common pattern was repetitive spikes. Seventy-five seizures (49%) had only one seizure onset pattern, and 79 seizures (51%) had a combination of seizure onset patterns. The degree of hippocampal gliosis strongly predicted the type of seizure onset pattern (Chi square = 24.07, 2 d.f., P < 0.01). The rhythmic activity pattern was associated with mild gliosis, and the repetitive spike pattern was associated with severe gliosis. We classified seizure onset as focal or regional based on the number of electrode contacts that were involved by the ictal EEG. A focal seizure onset was associated with an excellent outcome following temporal lobectomy.     

Statistical quality control methods in infection control and hospital epidemiology, Part II: Chart use, statistical properties, and research issues

This is the second in a two-part series discussing and illustrating the application of statistical process control (SPC) in hospital epidemiology. The basic philosophical and theoretical foundations of statistical quality control and their relation to epidemiology are emphasized in order to expand the mutual understanding and cross-fertilization between these two disciplines. Part I provided an overview of the philosophy and general approach of SPC, illustrated common types of control charts, and provided references for further information or statistical formulae. Part II now discusses alternate possible SPC approaches, statistical properties of control charts, chart-design issues and optimal control limit widths, some common misunderstandings, and more advanced issues. The focus of both articles is mostly nonmathematical, emphasizing important concepts and practical examples rather than academic theory and exhaustive calculations.     

A computerized approach to statistical quality control for radioimmunoassays in the clinical chemistry laboratory

Methods for statistical quality control for the clinical laboratory in general, and radioimmunoassay in particular, have been proposed for many years. Unfortunately, only a very small number of laboratories have adapted these procedures. By use of teletypes and other remote terminals, it is possible for all laboratories to access centralized computers where a general purpose quality control program can be stored. This relieves each laboratory of the costly task of developing software, provides some degree of inter-laboratory standardization and facilitates comparison of precision and accuracy between laboratories. A prototype program for this purpose is described. This program evaluates within-assay and between-assay variability, by means of an analysis of variance for a one-way classification random-effects model, and can monitor any assay parameter by use of control chart techniques. In addition, several tests are provided to evaluate the temporal stability of the assay system, and appropriate tests for outliers are included. Also, methods are described for combination of information from several quality control samples. This provides a valid basis for adjustment of assay results or for outright rejection of an assay. For convenience, this program is designed for output on a teletype or similar terminal located in the laboratory. Simplified versions of this program can be readily adapted to desk-top calculators. The original purpose for developing this system was to provide the clinical laboratory with a simple, general, and flexible method for assessing the performance of radioimmunoassays, but its usefulness should extend to virtually all assay methods.