Improper Testing Research Articles

Streptococcus suis, an Important Cause of Adult Bacterial Meningitis in Northern Vietnam

Background Streptococcus suis can cause severe systemic infection in adults exposed to infected pigs or after consumption of undercooked pig products. S. suis is often misdiagnosed, due to lack of awareness and improper testing. Here we report the first fifty cases diagnosed with S. suis infection in northern Viet Nam.Methodology/Principal FindingsIn 2007, diagnostics for S. suis were set up at a national hospital in Hanoi. That year there were 43 S. suis positive cerebrospinal fluid samples, of which S. suis could be cultured in 32 cases and 11 cases were only positive by PCR. Seven patients were blood culture positive for S. suis but CSF culture and PCR negative; making a total of 50 patients with laboratory confirmed S. suis infection in 2007. The number of S. suis cases peaked during the warmer months.Conclusions/Significance S. suis was commonly diagnosed as a cause of bacterial meningitis in adults in northern Viet Nam. In countries where there is intense and widespread exposure of humans to pigs, S. suis can be an important human pathogen.

Assessing the psychometric properties of the world assumptions scale

The notion that traumatic events shatter survivors' fundamental assumptions about the world has been accepted as a truism in the trauma literature, although tests of this hypothesis provide a somewhat mixed picture. Because this research has relied heavily on the World Assumptions Scale (WAS), it is unclear whether these inconsistent results are due to problems with assumptive world theory, improper tests of the theory, or problems with the WAS. Data were gathered from 742 undergraduate students at four universities to assess the psychometric properties of the WAS. Findings suggest several shortcomings of the WAS, including temporal instability, and mixed evidence regarding construct validity. Implications for trauma research are discussed.

Indiana Clinicians Achieve Key Legislative Repeal

Indiana Clinicians Achieve Key Legislative Repeal

LITIGATION OF MISSED CERVICAL SPINE INJURIES IN PATIENTS PRESENTING WITH BLUNT TRAUMATIC INJURY

Approximately 800,000 cervical spines are cleared in emergency departments each year. Errors in diagnosis of cervical spine injury are a potentially huge medicolegal liability, but no established protocol for clearance of the cervical spine is known to reduce errors or delays in diagnosis. The Lexis-Nexis, Westlaw, and Medline databases were queried for cases of missed cervical injury. Errors were categorized according to a novel system of classification. Type I errors occurred when inadequate or improper tests were ordered. Type II errors occurred when adequate tests were ordered, but were either misread or not read. Type III errors occurred when adequate tests were ordered and read accurately, but the ordered test was not sensitive enough to detect the injury. Twenty cases of missed or delayed diagnosis of cervical spine injury were found in 10 jurisdictions. Awards averaged 2.9 million dollars (inflation adjusted to 2002 dollars). Eight cases resulted in verdicts in favor of the defendant, but none of these cases involved an alleged Type II error. Fear of lawsuits encourages defensive medicine and complicates the process of clearing a patient's cervical spine. This analysis adds medicolegal support for the judicious use of imaging studies in current cervical spine clearance protocols. However, exposure to significant liability suggests that a low threshold for computed tomography is a reasonable alternative.

Reversible attenuation of voltage of QRS complexes and P waves and shortening of QRS duration and QTc interval consequent to large perioperative intravenous fluid infusions

A 39-year-old woman with a gangrenous pyelonephritis and septic shock underwent a nephrectomy, in preparation for which, she received large preoperative fluid resuscitation. Quantitative evaluation of her serial standard electrocardiograms (ECGs) revealed reversible attenuation of voltage in association with peripheral edema (PERE), with the latter being eventually completely abolished. The transient low-voltage ECG (LVECG) (attenuated amplitudes of QRS complexes) was associated with parallel transient attenuation of the amplitude of P waves and shortening of the QRS duration and QTc, whereas the P-wave duration increased. Awareness of these ECG changes with PERE of varying pathophysiologic mechanisms is useful, ensuring avoidance of improper procedural and laboratory testing and correct measurement of wave amplitudes and ECG time intervals for proper ECG diagnosis. In addition, these ECG associations can be used as indices of the presence and course of PERE postoperatively, as well as in a large variety of medical settings.

Contact Urticaria from Carboxymethylcellulose in White Chalk

Carboxymethylcellulose (CMC) is widely used in consumer goods, foods, and medicaments as a binder, emulsifier, and viscosity enhancer. Cases of immediate and delayed allergic reactions to this anionic cellulose polymer have been reported. To report a case of contact urticaria from CMC in chalk, with possible cross-reaction to methyl hydroxyethylcellulose (MHEC). Patch tests with readings at 48 and 96 hours were performed with the North American Contact Dermatitis Group standard series and benzisothiazolinone. Open and prick tests with readings after 30 minutes were performed with two brands of chalk as well as with various petrolatum and aqueous dilutions of CMC, MHEC, oleic acid, and calcium carbonate. The patient developed strong urticarial reactions during open tests with both powdered chalks and had milder reactions to the open test with CMC 10% aqueous (aq) and to prick testing with CMC 0.1% aq. No reaction to MHEC or any of the other ingredients of the chalks was observed. No relevant delayed reaction was noted. CMC can cause contact urticaria. It remains unclear why our patient reacted more strongly to the chalk than to CMC itself. We speculate that the abrasive nature of the chalk enhances the cutaneous penetration of CMC or that calcium carbonate, the main ingredient of the chalk, acts as an adjuvant. It is also possible that CMC and MHEC cross-react and that our negative results with MHEC may be due to improper testing technique or concentrations.

On the Anomaly of Cumulative Erosion and Abrasion-Time Curves

Abstract Erosion and abrasion-time curves of laboratory tests are of various forms. Most of these curves have a typical form, and are considered to be representative of erosion and abrasion phenomena. Other curves are considered anomalous; however, no definite explanations are offered for these irregularities. Analysis of the anomalous curves enables detection of the causes for these anomalies. The main causes detected for curve shape variation are: faulty test equipment, improper test procedure, variation in test specimen structure and properties, and wrong evaluation of test results.

Quality of the assessment of primary and secondary endpoints in claudication and critical leg ischemia trials

Clinical trials in peripheral arterial disease (PAD) require an accurate definition of the disease for inclusion; they typically use treadmill testing, questionnaires and hemodynamic measures as primary and secondary endpoints. Trials of new pharmacologic therapies for PAD often employ multiple clinical sites with presumed expertise in the diagnosis and management of PAD as well as in clinical trials. However, considerable variability has been observed in the assessment of endpoints used in PAD trials, as well as a marked placebo response with treadmill testing. This variability and placebo response impact adversely on overall trial integrity, necessitate an inflated sample size, and may contribute to the large number of recently negative claudication trials. We hypothesized that site monitoring visits for evaluating testing methods would identify and characterize several critical issues that would contribute to poor testing quality. One hundred sites participating in three claudication trials for which peak walking time on the treadmill was the primary endpoint, and 16 sites participating in a critical leg ischemia study for which transcutaneous oxygen tension (TcPO2) was the primary endpoint were evaluated. Each site was visited one or more times by a clinical monitor trained in conducting a 'site endpoint evaluation visit' focusing on equipment, physical set-up of the room in which testing was to be conducted, and the site staff's ability to conduct each of the specific measurements. Full reports were generated that covered a number of technical issues for each measurement and data were extracted from these reports to summarize the testing problems encountered at each site. Problems with treadmill testing were common. For example, 92% of sites had problems with their treadmill equipment, 58% did not perform proper treadmill familiarization, 24% did not start the treadmill test appropriately, 24% did not conduct the test properly, and 15% did not properly conclude the test to determine the peak walking time of the participant. Similar problems were encountered with the ankle-brachial index test, the administration of questionnaires and measurement of the TcPO2. Major deficiencies were identified at the majority of sites in the assessment of primary and secondary endpoints in PAD trials. These errors and improper testing provide a potential explanation for the wide variability and placebo responses observed in claudication and critical leg ischemia trials. Site interventions need to address these deficiencies in measurement to improve the quality of PAD trials.

Fifty Years of Research on the Intelligence of Deaf and Hard-of-Hearing Children: A Review of Literature and Discussion of Implications

In 1965, McCay Vernon drove a stake through the heart of the long-established "truth" that deaf people were inferior to hearing people. Launched by Aristotle, emboldened by the 1880 Conference of Milan, and reiterated in the twentieth century through the biased research of many psychologists, this falsehood persisted until the publication of this classic review paper. Vernon succinctly spotlights biases in IQ assessment of deaf children resulting from improper testing methods, research participant sampling, even the experience level of the evaluators themselves. Brief and scholarly, the paper had enormous impact not only on future research regarding cognition and deaf people but on clinical practice as well. Within this paper, insights are evident which Vernon has continued to elucidate throughout his long career. He was arguably the first psychologist to view the deaf population as a heterogeneous one, noting how various hearing loss etiologies differentially affect cognition and other psychological characteristics. His later research, notably that which focused on rubella, deafblind, and deaf forensic populations, has been similarly pioneering. McCay Vernon's extensive professional impact stems not only from his prolific, readily applied research work but also from his generous and vigorous activities as a teacher, a mentor, and advisor. - Robert Q. Pollard, Jr.

Geologic aspects of naturally fractured reservoirs

Most of today’s producing naturally fractured reservoirs were discovered accidentally; they were found by somebody who was looking for some other type of reservoir. That is one reason we should revisit the subject of how to explore for these reservoirs. Another is because (I am convinced) significant volumes of hydrocarbons reside in these reservoirs—particularly in fields abandoned because of improper testing and evaluation or because the wells did not intersect the natural fractures.

Analytical Performance of an Immunologic‐Based Periodontal Bacterial Test for Simultaneous Detection and Differentiation of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Prevotella intermedia

The analytical performance of a membrane-based immunoassay for the simultaneous detection and differentiation of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Prevotella intermedia (including Prevotella nigrescens) was investigated. Positive reactions were observed for 71 of 71 reference strains and recent oral isolates of A. actinomycetemcomitans, P. gingivalis, and P. intermedia. No cross-reactivity was observed with 39 other common oral and environmental species. The specificity of the test was unaffected by the presence of potential oral interferents including whole blood, white blood cells, mucin, saliva, toothpastes, and oral rinses. A proficiency test by dental professionals using a standardized set of unknown simulated samples yielded a sensitivity of 97% (116/120) and a 100% specificity (240/ 240). An additional group including dental professionals and high school students was shown to be 99% proficient (1385/1397) in distinguishing proper from improper test function when processing control samples with normal test devices and devices with simulated error conditions. Comparisons to a culture standard for 104 subgingival plaque samples collected from 26 adult periodontitis patients yielded > 98% specificity for each of the test bacteria. In addition, the detection threshold for the test was determined to be equivalent to 10(4) cultivable test bacteria when compared to the culture standard. The data indicate that this membrane immunoassay is a valid and easy-to-use method for the detection of A. actinomycetemcomitans, P. gingivalis, and P. intermedia in subgingival plaque, at levels above the detection threshold of the test.

Sampled signal reconstruction and Nyquist frequency

The discussion focuses only on those remarks of J. Lynn Smith (see ibid., p.14, May 1996) that were directly related to earlier comments (see ibid., p.41, July 1995). It complements Marple's (see ibid., p.24, January 1996) filter-bank analysis and tries to remove some clutter due to the improper test signals used. The frame of this discussion consist of the following three statements: the "successful" use of a sampling rate lower than the Nyquist rate is an illusion; the proposed method is nothing else than an analog form of the well-known filter banks, whose theory is consistent with the (correct) definition of the Nyquist frequency; and in general, the method can not be used with the zero-order hold operation, unless the filters are designed with frequency-dependent magnitude to compensate for the spectrum alteration produced by the sample-and-hold operation.

BASIC CONCEPTS IN BIOCHEMICAL ANTENATAL DIAGNOSIS

The biochemical test for each inherited metabolic disorder is unique. Each is complex and requires considerable experience for proper interpretation. All have inherent pitfalls that can be exaggerated by improper test procedures or inadequate tissue samples. An accurate prenatal diagnosis depends on having a reliable assay, competently performed, using a well-prepared sample.

False-negative urine latex particle agglutination testing in neonates with group B streptococcal bacteremia. A function of improper test implementation?

Although blood cultures remain the most specific indicator of Group B streptococcus (GBS) sepsis, a potentially life-threatening infection in neonates, test results may not be available for 24 to 48 hours. Detection of GBS antigen in the urine by latex particle agglutination (LPA) may speed diagnosis. This study analyzed the sensitivity of the GBS urine LPA assay under clinical conditions. The urine of neonates with early-onset GBS bacteremia was analyzed for GBS antigen over a three-year period at six military medical centers. Overall, 53.5% (38/71) of infants with positive blood cultures had a positive urine LPA test. Only one medical center routinely followed manufacturer's recommendations to concentrate urine specimens before testing. These data suggest that the sensitivity for the urine LPA assay, when performed on unconcentrated urine, is lower than previously reported. Clinicians should insist that the laboratory maximize sensitivity by concentrating urine prior to GBS LPA testing.

Denver Developmental Test Problems

To the Editor.— Although 80% of pediatricians feel that their training in assessing a child's development was inadequate,1 it is estimated that between 20 million to 30 million children have been screened worldwide with the Denver Developmental Screening Test.2 With ith so many children tested by so many inadequately trained physicians or their assistants, it is virtually unavoidable that the test sometimes will be used incorrectly. One effect of improper testing may be the not inconsiderable raising of anxiety among parents who are told that their children are developmentally delayed when in fact they are entirely normal.

Quantification of human error and common-mode failures in man-machine systems

An analysis of human errors in nuclear power plant systems when measured against common-mode failures (CMF) is presented. Human errors evaluated are improper testing, inadequate maintenance strategy, and miscalibration. The methodology improves power plant systems availability by identifying sources of common-mode failure when operational functions are involved. It is also applicable to other complex systems such as chemical plants, aircraft, and motor industries; in fact, any large man-created, man-machine system could be included.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Quantification of human error and common-mode failures in man-machine systems

An analysis is presented of human errors in nuclear-power-plant systems in conjunction with common-mode failures. The errors evaluated are improper testing, inadequate maintenance strategy, and miscalibration. The methodology used is believed to represent a positive contribution to power plant systems availability by identifying sources of common-mode failure when operational functions are involved. It is also applicable to other complex man-created, man-machine system.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Relationships among WISC-R Performance Categories and Measured Ethnic Identity in Black Adolescents

It is generally presumed that improper test interpretations, faulty norms, and examiners' biases contribute to the poor performance of blacks on intelligence tests. Standardization samples often do not include blacks; and when they do, the ethnic breakdown of the sample groups may not be given. Moreover, misuse of test scores has led to the misclassification of blacks as being intellectually inferior. 1 For a variety of reasons, it is generally accepted that within the United States there is substantial evidence that documents the poor test standing of blacks.2 This has far-reaching consequences which often prevent blacks from being accorded treatment that would maximize their development potential. The standardized intelligence test is especially prominent in this case. The Wechsler Intelligence Scale for Children-Revised (WISC-R) is considered a global measure of intelligence for children with varying cultural backgrounds. In comparing the test results of referred black, white, and Latino children in a prescribed geographic area on both the WISC and WISC-R scales, Swerdlick3 found the WISC-

Practical Testing of Diesel Generators

The testing of diesel generators is a very important facet of the safe operation of nuclear power plants. Improper testing can lead to increased failures and unavailability of the engines resulting in a reduced safety factor for a nuclear plant. For a testing program to be successful it must be well planned and effectively implemented. In addition, inspections and maintenance activities also impact diesel generator availability. This paper describes elements of a suggested diesel generator testing program as well as some of the pitfalls to be avoided.

Statistics of fracture of composite materials under multiaxial loading

A brittle fracture model is developed for composite structures with continuous aligned fiber reinforcement. Statistical data from the fracture of uniaxial coupons and information from a stress analysis are used to predict the fracture statistics of a brittle composite structure. The structure is divided into physically plausible subvolumes: these subvolumes must be large enough to contain the typical fracture-inducing flaw, thus minimizing element interactions, and small enough to have an approximately constant stress state within the volume. Probabilistic forms of various macroscopic fracture theories are applied to compute the subvolume reliabilities; the reliability for a subvolume is scaled according to its volume using a weak link model. These subvolume reliabilities are then combined to yield the structure reliability in a process analogous to numerical integration. The macroscopic fracture theories considered include the maximum stress, which leads to the principle of independent action, and the interactive maximum distortion energy criterion. The developed model is used to predict fracture statistics for a short off-axis specimen which experiences substantial stress concentrations because of its end constraints. Using data for a glass-epoxy system, the convergence of the method is illustrated by a progressive refinement of the maximum element size. The strength degradation induced by the geometric constraint is determined to be essentially constant. Results of the interactive and non-interactive criteria are compared for a graphite-epoxy system, demonstrating the conservatism of interactive criteria. The short off-axis specimen results show the potential effect of an improper test design on an anisotropic material.