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At least 631 records · Page 35Linked to original sources
PubMed2001

Methods of experimental and clinical assessment of the relative measurement accuracy of an intracranial pressure transducer. Technical note.

The assessment of the actual measurement accuracy of an intracranial pressure (ICP) transducer is imperative but still very difficult in practice. The authors tested the Codman MicroSensor ICP transducer experimentally. Additionally, a bedside test for assessment of measurement accuracy was used before and after clinical monitoring. For laboratory testing, seven new transducers were examined for measurement accuracy at increasing pressures ranging from 0 to 75 mm Hg. Drift was evaluated for 10 days at six different pressure levels ranging from 0 to 50 mm Hg. Temperature drift was assessed over a temperature range from 20 to 45 degrees C. The percentage absolute difference was used in the assessment of measurement accuracy. For clinical testing, measurement accuracy was assessed intraoperatively just before the insertion of the transducer and in an open water bath after its explantation, at 10 cm H2O both times. The maximum percentage absolute difference was 9% at a pressure of 10 mm Hg, and declined toward 2.3% at a pressure of 75 mm Hg. The maximum drift over 10 days was -4 mm Hg. Within the range of 30 to 40 degrees C, temperature drift was negligible. Over a period of 2 years, between June 1997 and June 1999, 40 ICP transducers were implanted in 35 patients by one surgeon. Of these devices, a malfunction was detected in two of them by testing them in a water bath before insertion. Experimental and clinical results indicate that this miniature strain-gauge transducer measures accurately; however, control readings for the probe by means of measurement in an open water bath just before insertion are strongly recommended.

Equipment Design↗
PubMed2001

An MKM-mounted instrument holder for frameless point-stereotactic procedures: a phantom-based accuracy evaluation.

To enable the use of the Mehrkoordinaten Manipulator (MKM) robotic navigation system for frameless point stereotactic procedures, a new instrument holder is presented. A phantom-based accuracy study was performed in which this new method was compared with frame-based procedures performed using the Brown-Roberts-Wells (BRW) stereotactic frame. The authors acquired computerized tomography scans of a test phantom, consisting of 19 acrylic plastic target rods on a circular base. These images were used in frame-based (BRW) and frameless (MKM) localization experiments. In both cases the authors calculated the distances between the actual target positions and the positions reached stereotactically. The mean application accuracy (target registration error) was 0.68 mm when the BRW frame was used and 0.96 mm when the MKM system was used after manual repositioning of the microscope (p < 0.001). Positioning accomplished using robotics only demonstrated a slightly larger inaccuracy: 1.47 mm (p < 0.005). Because the surgeon is concerned with the largest error in an individual case rather than the mean error in a large number of cases, the mean + three standard deviations was also compared. This value differed very little between the manually positioned MKM system and the BRW frame (2.04 mm and 1.84 mm, respectively). Although repeatability per target appeared to be slightly better when the BRW frame was used, accuracy was more homogeneous over the phantom volume when the MKM system was used (both differences were not significant). In conclusion, the accuracy of point stereotactic procedures performed using an instrument holder attached to the system is comparable with the accuracy of procedures involving a stereotactic frame. Moreover, the frameless techniques and robotic features of the MKM enable a more surgeon- and patient-friendly stereotactic procedure.

Biopsy↗
PubMed2004

Geometrical accuracy of the Novalis stereotactic radiosurgery system for trigeminal neuralgia.

OBJECT: Stringent geometrical accuracy and precision are required in the stereotactic radiosurgical treatment of patients. Accurate targeting is especially important when treating a patient in a single fraction of a very high radiation dose (90 Gy) to a small target such as that used in the treatment of trigeminal neuralgia (3 to 4-mm diameter). The purpose of this study was to determine the inaccuracies in each step of the procedure including imaging, fusion, treatment planning, and finally the treatment. The authors implemented a detailed quality-assurance program. METHODS: Overall geometrical accuracy of the Novalis stereotactic system was evaluated using a Radionics Geometric Phantom Chamber. The phantom has several magnetic resonance (MR) and computerized tomography (CT) imaging-friendly objects of various shapes and sizes. Axial 1-mm-thick MR and CT images of the phantom were acquired using a T1-weighted three-dimensional spoiled gradient recalled pulse sequence and the CT scanning protocols used clinically in patients. The absolute errors due to MR image distortion, CT scan resolution, and the image fusion inaccuracies were measured knowing the exact physical dimensions of the objects in the phantom. The isocentric accuracy of the Novalis gantry and the patient support system was measured using the Winston-Lutz test. Because inaccuracies are cumulative, to calculate the system's overall spatial accuracy, the root mean square (RMS) of all the errors was calculated. To validate the accuracy of the technique, a 1.5-mm-diameter spherical marker taped on top of a radiochromic film was fixed parallel to the x-z plane of the stereotactic coordinate system inside the phantom. The marker was defined as a target on the CT images, and seven noncoplanar circular arcs were used to treat the target on the film. The calculated system RMS value was then correlated with the position of the target and the highest density on the radiochromic film. The mean spatial errors due to image fusion and MR imaging were 0.41+/-0.3 and 0.22+/-0.1 mm, respectively. Gantry and couch isocentricities were 0.3+/-0.1 and 0.6+/-0.15 mm, respectively. The system overall RMS values were 0.9 and 0.6 mm with and without the couch errors included, respectively (isocenter variations due to couch rotation are microadjusted between couch positions). The positional verification of the marker was within 0.7+/-0.1 mm of the highest optical density on the radiochromic film, correlating well with the system's overall RMS value. The overall mean system deviation was 0.32+/-0.42 mm. CONCLUSIONS: The highest spatial errors were caused by image fusion and gantry rotation. A comprehensive quality-assurance program was developed for the authors' stereotactic radiosurgery program that includes medical imaging, linear accelerator mechanical isocentricity, and treatment delivery. For a successful treatment of trigeminal neuralgia with a 4-mm cone, the overall RMS value of equal to or less than 1 mm must be guaranteed.

Equipment Design↗
PubMed2003

Diagnostic accuracy of magnetic resonance imaging for detecting posterior ligamentous complex injury associated with thoracic and lumbar fractures.

OBJECT: The posterior ligamentous complex (PLC) in the thoracic and lumbar spine is one of the region's important stabilizers. The precise diagnosis of PLC injury is required to evaluate the instability of the injured spine; however, the accuracy of magnetic resonance (MR) imaging for diagnosing PLC injury has remained unclear. In this study, the authors compared preoperative MR imaging findings with direct intraoperative observation of PLC injury, clarifying the former's diagnostic accuracy regarding detection of PLC injury associated with the thoracic and lumbar fractures. METHODS: Data obtained in 35 patients who sustained thoracic or lumbar injuries were reviewed. There were 17 burst fractures, six flexion-distraction injuries, and 12 fracture dislocations. Each patient underwent MR imaging examination within 3 weeks of injury. Three radiologists independently evaluated sagittal MR images in a blinded fashion. The PLC-related information was retrospectively collected from each operative record. The diagnostic accuracy of MR imaging was analyzed by comparing imaging-documented intraoperative findings. The PLC injuries were detected in 23 patients (65.7%) by direct observation during posterior spinal procedures. The diagnostic accuracy of MR imaging in detecting injury of the supraspinous ligament (SSL) and interspinous ligament (ISL) was 90.5 and 94.3%, respectively. The specificity of T1-weighted MR imaging alone for depicting the SSL was significantly greater than T2-weighted imaging alone (p < 0.05). The overall mean kappa coefficient for MR imaging findings of PLC injury was 0.803, which indicated excellent interobserver reliability; that for ISL (0.915) was significantly greater than that for SSL (0.69) (p < 0.05). CONCLUSIONS: This study clarified a high diagnostic accuracy and interobserver reliability of MR imaging for PLC injury. The precise diagnosis of PLC injury is essential to determine the mechanical instability of the injured thoracic and lumbar spine, especially in differentiating unstable (three-column) burst fractures from the relatively stable (two-column) type. The authors conclude that MR imaging is a powerful diagnostic tool to evaluate PLC injury associated with thoracic and lumbar fractures.

Humans↗
PubMed2005

A methodological review of how heterogeneity has been examined in systematic reviews of diagnostic test accuracy.

OBJECTIVES: To review how heterogeneity has been examined in systematic reviews of diagnostic test accuracy studies. DATA SOURCES: Centre for Reviews and Dissemination's Database of Abstracts of Reviews of Effects (DARE). REVIEW METHODS: Systematic reviews that evaluated a diagnostic or screening test by including studies that compared a test with a reference test were identified from DARE. Reviews for which structured abstracts had been written up to December 2002 were screened for inclusion. Data extraction was undertaken using standardised data extraction forms. RESULTS: A total of 189 systematic reviews met the inclusion criteria. The median number of studies included was 18. Meta-analyses have a higher number with a median of 22 studies compared with 11 for narrative reviews. Graphical plots to demonstrate the spread in study results were provided in 56% of meta-analyses; in 79% these were plots of sensitivity and specificity in the receiver operating characteristic (ROC) space. Statistical tests to identify heterogeneity were used in 32% of reviews: 41% of meta-analyses and 9% of reviews using narrative syntheses. The chi-squared test and Fisher's exact test to assess heterogeneity in individual aspects of test performance were the most common. In contrast, only 16% of meta-analyses used correlation coefficients to test for a threshold effect. A narrative synthesis was used in 30% of reviews. Of the meta-analyses, 52% carried out statistical pooling alone, 18% conducted only summary receiver operator characteristic (SROC) analyses and 30% used both methods of statistical synthesis. For those undertaking SROC analyses, the main differences between the models used were the weights chosen for the regression models, although in 42% of cases the use of, or choice of, weight was not provided. The proportion of reviews using statistical pooling alone has declined from 67% in 1995 to 42% in 2001, with a corresponding increase in the use of SROC methods, from 33% to 58%. However, two-thirds of those using SROC methods also carried out statistical pooling rather than presenting only SROC models. Reviews using SROC analyses also tended to present their results as some combination of sensitivity and specificity rather than using alternative, perhaps less clinically meaningful, means of data presentation such as diagnostic odds ratios. Three-quarters of meta-analyses attempted to investigate statistically possible sources of variation, using subgroup analysis or regression analysis. The impact of clinical or socio-demographic variables was investigated in 74% of these reviews and test- or threshold-related variables in 79%. At least one quality-related variable was investigated in 63% of reviews. Within this subset, the most commonly considered variables were the use of blinding, sample size, the reference test used and the avoidance of verification bias. CONCLUSIONS: The emphasis on pooling individual aspects of diagnostic test performance and the under-use of statistical tests and graphical approaches to identify heterogeneity perhaps reflect the uncertainty in the most appropriate methods to use and also greater familiarity with more traditional indices of test accuracy. This indicates the difficulty and complexity of carrying out such reviews. In these cases it is strongly suggested that meta-analyses are carried out with the involvement of a statistician familiar with the field. Further methodological work on the statistical methods available for combining diagnostic test accuracy studies is needed, as are sufficiently large, prospectively designed primary studies of diagnostic test accuracy comparing two or more tests for the same target disorder. Use of individual patient data meta-analysis in diagnostic test accuracy reviews should be explored to allow heterogeneity to be considered in more detail.

Diagnostic Tests, Routine↗
PubMed2006

Accuracy of intra-articular injection of the glenohumeral joint: a cadaveric study.

Intra-articular glenohumeral injections are an important part of orthopedic practices for both therapeutic and diagnostic purposes. Forty human cadaver shoulders were injected, 20 anteriorly and 20 posteriorly, to assess the accuracy of injections placed in the glenohumeral joint. After the needle was placed, 1 cc of gadolinium was injected into the joint to determine accuracy of position. The radiographic presence of intra-articular contrast was judged as an accurate injection. The anterior approach had an 80% accuracy rate and .75 positive predictive value. The posterior approach had a 50% accuracy rate and a .67 positive predictive value. Anterior injections produce a higher rate of accuracy than posterior injections.

Aged↗
PubMedDate not supplied

Accuracy and clinical correlates of two different methods for chromogranin A assay in neuroendocrine tumors.

Measurement of chromogranin A (CgA) plays a major role in the management of neuroendocrine tumors (NET); however, reliable assaying of CgA is made difficult by the rapid hydrolysis following its release into the bloodstream. This study was aimed at the assessment of two assays for CgA in NET patients. CgA was measured in 93 patients by means of an enzyme-linked immunosorbent assay (ELISA) and an immunoradiometric assay (IRMA). The specificity and sensitivity of CgA were evaluated in relation to tumor histology. The clinical accuracy of the two assays was evaluated by receiver-operating characteristic (ROC) curve analysis. Regression analysis demonstrated different immunoreactivity for CgA of the antibodies used in the two kits (r = 0.61). The two assays had different accuracy also in classifying patients according to their clinical condition (91% vs 64% specificity and 79% vs 79% sensitivity for the ELISA and IRMA assay, respectively) and tumor histology (81% vs 85% sensitivity for the ELISA and IRMA assays, respectively, in carcinoids; 92% vs 67% sensitivity for the ELISA and IRMA assays, respectively, in pancreatic islet cell tumors). The different clinical accuracy of the two assays was confirmed by the ROC analysis (AUC = 0.90 vs AUC = 0.87 for the ELISA and IRMA assays, respectively). In conclusion, because of the poor standardization of the commercially available measurement tools the clinical accuracy of CgA measurement depends on the assay used. This makes it difficult to compare CgA values measured with different kits and affects the clinical accuracy of the different assays for CgA.

Adolescent↗
PubMed1989

[Accuracy of computed tomography in the staging of renal cell carcinoma].

Computed tomography (CT) was performed in a total 124 cases of renal cell carcinoma to determine perinephric invasion, venous invasion and involvement of the regional lymph node. The findings obtained were compared with pathological findings. CT findings for invasion of perinephric fat showed a sensitivity of 82%, specificity of 82 and accuracy of 82%. For adjacent organ invasion CT findings revealed a sensitivity of 90%, specificity of 100% and accuracy of 99%. As to venous invasion CT findings showed a sensitivity of 86%, specificity of 97%, and accuracy of 95%, and for lymph node involvement CT findings revealed a sensitivity of 80%, specificity of 98%, accuracy of 96%. Although the accuracy is not so high in diagnosing invasion of perinephric fat, CT scan was proven to be a valuable diagnostic measure for detection of adjacent organ invasion, venous invasion and lymph node involvement, thus helping to select a suitable surgical approach.

Adult↗
PubMed1999

Surgical residents and ultrasound technician accuracy and cost-effectiveness of ultrasound in trauma.

The purpose of this study is 2-fold: 1) to assess the accuracy of the Focused Abdominal Sonogram for Trauma (FAST) as an important evaluative tool for the trauma victim as compared with other objective testing resources (i.e., computerized axial tomography scan); and 2) to analyze the cost-effectiveness of FAST as performed by surgical residents as compared with ultrasound (US) technicians. FAST was performed on 650 trauma victims over a period of 12 months. Testing was completed in a trauma room of the emergency department by an US technician or a trauma surgical resident as determined by the availability of the US technician. Hypotensive patients required two FASTs to be completed for comparison of results. Persistent difficulty interpreting the FAST required the addition of a computerized axial tomography scan to help clarify the results. Statistical analysis was performed using chi2 and analysis of variance. False positive, false negative, and true positive, true negative, along with the accuracy of FAST were calculated as compared with other diagnostic testing. The finding indicated that FAST was both specific (99 per cent) and sensitive (68 per cent) in the sample used. Of the 650 patients receiving FAST, true negative was 95 per cent, true positive was 3 per cent as compared with false negative at 1 per cent, and false positive at 0.5 per cent. US technicians performed 81 per cent of the FASTs with an accuracy of 92 per cent. In comparison, surgical residents had a 92 per cent rate of accuracy in the remaining 19 per cent of the population. The mean accuracy of both was 94 per cent. Furthermore, FAST as performed by resident incurred a single fee of $88 for radiological readings as compared with $274 for an US technician fee plus the radiological reading fee of $88. FAST as performed by surgical residents is more cost-effective than FAST as performed by an US technician.

Abdominal Injuries↗
PubMed1999

Competency-based instruction to improve the surgical resident technique and accuracy of the trauma ultrasound.

In a surgical trauma center, programs and workshops have improved the performance on focused abdominal sonogram for trauma (FAST). The purpose of this single-blind study was to prove that a cadaver laboratory competency-based instruction program may be an effective method of FAST training to acquire the skills that would be applied in the trauma room. The study was divided in two parts, laboratory and clinical. Nine surgical residents were divided into two groups: Group I performed the test only once, and Group II performed the training twice. A third "group" was the senior ultrasound technician, whose readings served as our "gold standard" with which to compare the resident readings (Group III). Using cadavers, a 2-cm catheter was introduced into the peritoneal cavity. Sequential aliquots of normal saline were introduced into the abdominal cavity at 0-, 200-, 400-, 600-, and 1000-cc increments in each group tested. The residents were asked to describe their examinations for the presence or absence of fluid in the abdomen. The ultrasound examination was then performed with the cadaver in three different positions to study if there was any difference of fluid detection in varied positions. True positive, true negative, and accuracy were then calculated comparing the three different groups of test sonographers. In the second part of the study, the same residents were then followed in the trauma room, where they performed the FAST in the absence of the ultrasound technician during emergencies. As in the laboratory, the accuracy of their reading compared with that of the ultrasound technician was also evaluated. From 400 cc and upward, Group II began having an overall significantly superior accuracy than the first group and the technician in most quadrants examined. The trend was apparent for more accurate results in all quadrants and positions by all groups as the fluid was increased. Overall, group II was most superior in detection of intra-abdominal fluid in the cadaver. In the clinical scenario, the residents as a whole had similar accuracy (92% vs 96%) in reading FAST as the ultrasound technician. Our results suggest that surgical residents have the ability to detect fluid in the abdomen, there exists a fast learning curve, and the minimum detection level of fluid was between 200 and 400 cc in the peritoneal cavity in the laboratory. Surgical residents were able to detect intra-abdominal fluid in the trauma situation, as shown by the 92 per cent accuracy of the FAST in the emergency situation. We conclude that a cadaver laboratory training program is an important adjunct to improve the skills of the resident in performing and reading FAST.

Analysis of Variance↗
PubMedDate not supplied

[Accuracy of imaging techniques and tumor markers in the diagnosis of pancreatic cancer].

OBJECTIVE: The aim of this study was to evaluate the diagnostic accuracy of: a) three imaging techniques: ultrasonography (US), computed tomography (CT) and endoscopic retrograde cholangiopancreatography (ERCP), and b) the serum tumor markers CEA, CA 19-9 and CA 125, in the diagnosis of pancreatic cancer. PATIENTS AND METHODS: A total of 137 patients were prospectively evaluated. Pancreatic cancer was diagnosed in 25 patients; chronic pancreatitis in 24; acute pancreatitis in 22; extrapancreatic malignancies in 24, and benign digestive disease in 42. The reference interval for each marker was determined in 36 healthy volunteers. Diagnostic accuracy was determined using receiver operating characteristic (ROC) curves. Each diagnostic test was used in order: a) to diagnose pancreatic cancer when the disease was clinically suspected, and b) to differentiate between pancreatic cancer and chronic pancreatitis. RESULTS: CT (0.976-0.888) and US (0.857) diagnostic accuracy resulted greater than the best serum tumor marker CA 19-9 (0.755-0.786) (p = NS), in both diagnostic conditions. To obtain a diagnostic specificity of 90% in pancreatic cancer, the CA 19-9 cutoff level should increase up to 3 and 7.5 folds being in this case better than CEA and CA 125 (p < 0.05). CONCLUSIONS: CT scan offers the greatest accuracy in the diagnosis of PC. Among the tumor markers, CA 19-9 offers the best accuracy in the diagnosis of pancreatic cancer.

Acute Disease↗
PubMed2000

Proton MR spectroscopy and preoperative diagnostic accuracy: an evaluation of intracranial mass lesions characterized by stereotactic biopsy findings.

BACKGROUND AND PURPOSE: MR imaging has made it easier to distinguish among the different types of intracranial mass lesions. Nevertheless, it is sometimes impossible to base a diagnosis solely on clinical and neuroradiologic findings, and, in these cases, biopsy must be performed. The purpose of this study was to evaluate the hypothesis that proton MR spectroscopy is able to improve preoperative diagnostic accuracy in cases of intracranial tumors and may therefore obviate stereotactic biopsy. METHODS: Twenty-six patients with intracranial tumors underwent MR imaging, proton MR spectroscopy, and stereotactic biopsy. MR spectroscopic findings were evaluated for the distribution pattern of pathologic spectra (NAA/Cho ratio < 1) across the lesion and neighboring tissue, for signal ratios in different tumor types, and for their potential to improve preoperative diagnostic accuracy. RESULTS: Gliomas and lymphomas showed pathologic spectra outside the area of contrast enhancement while four nonastrocytic circumscribed tumors (meningioma, pineocytoma, metastasis, and germinoma) showed no pathologic spectra outside the region of enhancement. No significant correlation was found between different tumor types and signal ratios. MR spectroscopy improved diagnostic accuracy by differentiating infiltrative from circumscribed tumors; however, diagnostic accuracy was not improved in terms of differentiating the types of infiltrative or circumscribed lesions. CONCLUSION: MR spectroscopy can improve diagnostic accuracy by differentiating circumscribed brain lesions from histologically infiltrating processes, which may be difficult or impossible solely on the basis of clinical or neuroradiologic findings.

Adult↗
PubMed2000

Toward a checklist for reporting of studies of diagnostic accuracy of medical tests.

BACKGROUND: : "Diagnostic accuracy" refers to the ability of medical tests to provide accurate information about diagnosis, prognosis, risk of disease, and other clinical issues. Published reports on diagnostic accuracy of medical tests frequently fail to adhere to minimal clinical epidemiological standards, and such failures lead to overly optimistic assessments of evaluated tests. Our aim was to enumerate key items for inclusion in published reports on diagnostic accuracy, with a related aim of making the reports more useful for systematic reviews. METHODS: : We examined published reports on shortcomings of studies of diagnostic accuracy. We prepared an initial draft of a checklist to address common errors and presented it at a meeting of editors. After incorporation of comments from editors, we published a revised version in Clinical Chemistry in 1997 for comment from readers. One of us (E.M.) additionally circulated copies of the draft to methodologists and others interested in Evidence-Based Medicine. We updated the checklist with input from these sources. RESULTS: : The updated document lists items for inclusion in the title, abstract, methods, results, and discussion sections of published papers. Depending on the nature of the study, the total number of items for a single paper is approximately 40. We invite comments on this document, which is freely available at Clinical Chemistry Online, where it can accessed readily from the Table of Contents for the July 2000 issue at www. clinchem.org/content/vol46/issue7/. Comments (eLetters) can be posted there for general reading. CONCLUSIONS: : The suggested revisions incorporated in this report appear useful to ensure inclusion of additional information that can allow assessment of the validity of the conclusions and the applicability of the study in other settings. The list can be useful in formulating guidelines and a checklist, which will require testing by authors and study of their effect on published studies of diagnostic accuracy.

Clinical Chemistry Tests↗
PubMed1975

The accuracy of calcium analysis in the United States.

The accuracy of the methods commonly used for calcium analysis in clinical laboratories in the United States was studied with the aid of the National Bureau of Standards (NBS). Samples from six large serum pools that had been analyzed by 4,258 clinical laboratories were sent to NBS. At NBS the calcium contents of the samples were determined using isotope dilution and mass spectrometry (ID-MS). The findings show that the bias of the routine methods varies from levels that are insignificant to levels that would have an impact on patient care. The accuracy of the automated methods is comparable to the accuracy of the best manual methods. The accuracy of the proposed calcium reference method is comparable to the accuracy of a number of the methods in current routine use. There is evidence of a widespread lack of standardization at the extremes of the clinical range; this effect is not shown by the results obtained by automated methods. The study underlines the value of developing technology, such as ID-MS, that is capable of providing definitive values. The definitive values can then be used to assess the bias of routine methods on a nationwide scale, using existing programs.

Autoanalysis↗
PubMed2001

Detection of alcohol abuse in neurological patients: variables of clinical relevance to the accuracy of the %CDT-TIA and CDTect methods.

OBJECTIVES: Alcohol-related neurological diseases are encountered frequently. Early diagnosis is essential, because minimal intervention effectively reduces hazardous alcohol consumption and may prevent permanent neurological damage. Carbohydrate-deficient transferrin (CDT) is a valuable tool for the identification of alcohol abuse, but for unselected patient populations, reduced test accuracy has been reported. Recently, factors other than alcohol use have been shown to influence CDT levels. Our aim was to identify clinically relevant factors that might reduce test accuracy. MATERIAL AND METHODS: We included 397 neurological patients consecutively hospitalized for seizures, ischemic stroke, or sciatica and 87 patients who attended routine outpatient controls for epilepsy. Blood samples were analyzed for CDT by using two commercially available tests, %CDT-TIA and CDTect. All patients underwent a semistructured clinical interview that included a record of the reported ethanol consumption during the last 8 days, and all completed the Alcohol Use Disorders Identification Test (AUDIT). Current medication, medical history, and demographic information also were obtained. RESULTS: Both tests were elevated in female antiepileptic drug users, compared with others who reported no recent ethanol intake. A higher number of false-positive cases was seen for CDTect than for %CDT. Various combinations of CDT and gamma-glutamyltransferase improved sensitivity, but at the cost of reduced specificity. Variables that predicted the variation of CDT included antiepileptic drug use, sex, body mass index, and smoking. Total transferrin levels were reduced significantly in postmenopausal women, whereas a falling trend was seen for CDTect. Transferrin alterations caused a higher number of false-positive results for CDTect than for %CDT. The area under the receiver operating characteristics curve for women was higher for CDTect than for %CDT, and for %CDT, the area under the receiver operating characteristics curve was higher for men than for women. CONCLUSION: The accuracy of CDT for detection of alcohol abuse in neurological patients was generally low, particularly for women. Combination variables of CDT and gamma-glutamyltransferase did not increase test accuracy. Variables that were associated with higher CDT levels included female sex, antiepileptic drug use, transferrin alterations, and possibly low body mass index. When factors known to cause poor accuracy in particular patient groups are appreciated, CDT may be a good adjunct to the clinical examination.

Adult↗
PubMedDate not supplied

Accuracy of CPT evaluation and management coding by family physicians.

BACKGROUND: Limited data are available on physicians' accuracy in coding for their services. The purpose of this study was to determine the current procedural terminology (CPT) evaluation and management coding accuracy of family physicians and define demographic variables associated with coding accuracy. METHODS: Six hundred randomly selected active members of the Illinois Academy of Family Physicians were sent six hypothetical progress notes of office visits along with a demographic survey. The study group assigned CPT evaluation and management codes to each of the progress notes and completed the demographic survey. Five expert coders also assigned codes to each of the cases. The accuracy of family physicians in determining CPT E/M codes was determined relative to that of expert coders. RESULTS: Family physicians agreed with the experts' CPT evaluation and management codes for 52% of established patient progress notes, the most common error being undercoding. In contrast, for new patient progress notes, family physicians agreed with the experts only 17% of the time, the predominant error being overcoding. No surveyed demographic variable was associated with coding accuracy. CONCLUSIONS: The error rate for physician CPT coding is substantial and occurs more commonly with new patients. The complexity of the CPT coding guidelines, along with limited physician training in CPT coding, likely account for these results.

Ambulatory Care↗
PubMed2001

Definition and assessment of sampling and analytical accuracy.

Two independent definitions for quantifying measurement accuracy and two limiting schemes for their assessment are examined in this paper. Gauss' mean square error MSE is compared to the symmetric-range accuracy A, describing the range of measurements about a measurand. Both measures of accuracy account for systematic error (bias) and imprecision so as to quantify the closeness of estimates to the actual values being measured. Remarkably, it is found that the accuracy functions are closely equivalent for most method applications. Furthermore, details are presented on how to compute confidence limits on measurement accuracy so as to account for error in method evaluation. The confidence limits are qualitatively different in the case that the method undergoes extensive initial evaluation in comparison to a continual re-evaluation at each method application. To this end the statistical theories of tolerance as well as more familiar types of confidence intervals are applied.

Bias↗
PubMedDate not supplied

Accuracy of electronic implant torque controllers following time in clinical service.

Tightening of the screws in implant-supported restorations has been reported to be problematic, in that if the applied torque is too low, screw loosening occurs. If the torque is too high, then screw fracture can take place. Thus, accuracy of the torque driver is of the utmost importance. This study evaluated 4 new electronic torque drivers (controls) and 10 test electronic torque drivers, which had been in clinical service for a minimum of 5 years. Torque values of the test drivers were measured and were compared with the control values using a 1-way analysis of variance. Torque delivery accuracy was measured using a technique that simulated the clinical situation. In vivo, the torque driver turns the screw until the selected tightening torque is reached. In this laboratory experiment, an implant, along with an attached abutment and abutment gold screw, was held firmly in a Tohnichi torque gauge. Calibration accuracy for the Tohnichi is +/- 3% of the scale value. During torque measurement, the gold screw turned a minimum of 180 degrees before contact was made between the screw and abutment. Three torque values (10, 20, and 32 N-cm) were evaluated, at both high- and low-speed settings. The recorded torque measurements indicated that the 10 test electronic torque drivers maintained a torque delivery accuracy equivalent to the 4 new (unused) units. Judging from the torque output values obtained from the 10 test units, the clinical use of the electronic torque driver suggests that accuracy did not change significantly over the 5-year period of clinical service.

Analysis of Variance↗