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PubMed1989

Diagnostic accuracy of sialic acid in the diagnosis of malignant ascites.

The authors evaluated the diagnostic accuracy of sialic acid and its lipid-bound fraction in ascites and compared these tests with others (fibronectin, cholesterol) recently claimed as valuable in the differential diagnosis of ascites. Fibronectin yielded the best diagnostic accuracy (85%) with no false-positive and 37% of false-negative (10/27). The authors also found higher concentration of sialic acid in malignant ascites than in nonmalignant ascites (P less than 0.001) and, taking 300 mg/l as the cutoff value, the false-positive rate was 10% (four of 40), the false-negative rate 30% (eight of 27), and the overall diagnostic accuracy 82%, comparable to that of the fibronectin. The authors conclude that both fibronectin and sialic acid determinations in ascites may be regarded as accurate markers of neoplastic involvement of the peritoneum, although no test is useful in the ascites with hepatocellular carcinoma and cirrhosis of the liver.

Ascites↗
PubMed2001

Eating disorders, dieting, and the accuracy of self-reported weight.

OBJECTIVE: This study investigated the accuracy of self-reported weight and height in individuals with an eating disorder (i.e., anorexia nervosa [AN] and bulimia nervosa [BN]) and in individuals without an eating disorder (i.e., dieters and nondieters). METHOD: Self-reported and measured weights and heights were obtained from the eating disorder sample (n = 81) and the college student sample (n = 163) and were compared within and between the groups. RESULTS: Eating disorder patients were extremely accurate at self-reporting their weight. However, there was a significant difference in accuracy between AN and BN patients. AN patients slightly overreported their weight, whereas BN patients slightly underreported their weight. Both dieters and nondieters significantly underreported their weight. However, dieters significantly underreported their weight to a greater degree than did the nondieters. DISCUSSION: The implications of these subgroup differences and their specificity to weight reporting are discussed with reference to the accuracy of self-reported height.

Adult↗
PubMedDate not supplied

Prenatal cytogenetic diagnosis of the fragile X syndrome in amniotic fluid: calculation of accuracy.

We have completed over 350 prenatal diagnoses for the fragile X [fra(X)] syndrome using amniotic fluid, chorion villus specimen (CVS), fetal blood sampling and molecular methods. A total of 300 amniotic fluid specimens have been received for prenatal diagnosis of the fra(X) syndrome. There was a documented family history of fra(X) in 170/300 amniotic fluid cases, and 23/170 were correctly identified as cytogenetically fra(X) positive (16 male; 7 female). Three males were false-negative, and one female was fra(X) negative but identified as a probable carrier by RFLPs. No fra(X) positive or false-negative results were found in the absence of a fra(X) family history. Because the a priori risk for the fra(X) syndrome for each pregnancy was different and widely variable, the determination of the accuracy of the prenatal diagnosis results requires a consideration of these variables. On this basis, the calculated accuracy of prenatal cytogenetic diagnosis for the fra(X) syndrome is approximately 97%. This accuracy can be improved further with the simultaneous use of molecular methods, especially in view of recent developments.

Cytogenetics↗
PubMed1991

Tests of EEG localization accuracy using implanted sources in the human brain.

The accuracy with which electrical sources in the brain can be localized by using electroencephalograms measured on the scalp is not well known. In this study, tests of localization accuracy were performed by using implanted dipolar sources in the human brain. These dipoles are created by passing a weak (subthreshold) current through intracerebral electrodes implanted in the brains of epileptic patients for seizure monitoring. The locations of these dipoles are accurately known from roentgenographs. First, 16 electroencephalograms produced by these dipoles were recorded, then inverse solutions were calculated for the apparent sources of these electroencephalograms. Finally, the locations of the apparent sources were compared with the known locations of the implanted dipoles to determine localization error. The average localization error for a total of 28 dipoles in 3 subjects was 1.1 cm. These results indicate that good localization accuracy for focal sources in the brain can be provided by scalp electroencephalograms.

Brain↗
PubMed2004

Accuracy of Veterans Administration databases for a diagnosis of rheumatoid arthritis.

OBJECTIVE: To determine the accuracy of International Classification of Diseases (ICD) code 714 for rheumatoid arthritis (RA) diagnosis in a Veterans Administration (VA) hospital database and to examine the effects of adding laboratory and pharmacy data to ICD code 714 on accuracy of RA diagnosis. METHODS: We drew a random sample of patients from all Minneapolis VA rheumatology clinic patients who had at least 1 rheumatology clinic visit between January 2001 and July 2002. Charts of 184 patients were reviewed. The gold standard for RA diagnosis was chart documentation of RA diagnosis by a rheumatologist on > or =2 visits >6 weeks apart. The data definitions of RA diagnosis included presence of ICD code 714 alone or various combinations of ICD code 714, a positive rheumatoid factor (RF), and prescription for a disease-modifying antirheumatic drug (DMARD). Accuracy of data definitions of RA was assessed by calculating sensitivity, specificity, positive and negative predictive values, and area under the receiver operator characteristics curve. RESULTS: Diagnosis by ICD code 714 had 100% sensitivity, but specificity was only 55% because of a false-positive rate of 34%. The addition of a positive RF and/or a DMARD prescription to ICD code 714 dramatically improved specificity to 83-97% and positive predictive value to 81-97%; however, sensitivity decreased to 76-88%. Diagnosis by ICD 714 alone had the highest negative predicative value of 100%. The area under the curve was the greatest when both ICD code 714 and a positive RF were included, and the least when ICD code alone was used. CONCLUSION: ICD code 714 in the VA administrative database is a very sensitive screening tool for identifying patients with RA in the rheumatology clinic population. Addition of the presence of a DMARD prescription and/or a positive RF to selection criteria improves specificity of the diagnosis.

Aged↗
PubMed1976

A retrospective analysis of the accuracy of immediate frozen section diagnosis in surgical pathology.

An evaluation of the accuracy of 3556 frozen section diagnoses over a 10-year period has been carried out. The overall accuracy rate was 97.4 per cent, with umimportant discrepancies present in a further 1.8 per cent. In only 28 cases (0.8 per cent) was a false negative or positive diagnosis of malignancy made. Of these, 4 patients underwent an unnecessary radical operation, while in 9 patients further surgery had to be carried out at a later date. The essential accuracy of the frozen section technique is confirmed.

Diagnostic Errors↗
PubMed1987

Quantitative analysis of S3341 in human plasma and urine by combined gas chromatography-negative ion chemical ionization mass spectrometry: 15 month inter-day precision and accuracy validation.

A new quantitative assay for the determination of S3341, an alpha-2 agonist antihypertensive drug, has been developed using combined gas chromatography-negative ion chemical ionization mass spectrometry. The [M]-. ions from TFA derivatives of S3341 (m/z 276) and the internal standard (2H4)S3341 (m/z 280) are monitored simultaneously by selected ion monitoring. For S3341 concentrations ranging from the limit of detection (0.2 ng ml-1 using 1 ml of plasma) to 5 ng ml-1, the average assay precision (CV) is approximately 7% while the average assay accuracy (percentage of error) is 4%. Validation of the day-to-day precision and accuracy was realized after analysing control plasma samples (n = 295) concurrently with the biological samples collected during the pharmacokinetic studies conducted over 15 months. The average day-to-day precision (CV) and accuracy (percentage of error) are 10% and 6% respectively, thus indicating that this assay procedure routinely provides reliable analytical data.

Adrenergic alpha-Agonists↗
PubMed2005

Accuracy of self-reported arrests among a forensic SPMI population.

Self-reports are prone to response error even in the most structured and standardized environment, but the highly stigmatizing nature of illegal behavior and the possible cognitive problems inherent to the SPMI population increase the likelihood of such error. Using administrative data as the gold standard, the validity of self-reported arrests was examined among 85 mentally ill substance-abusing individuals with justice involvement. The overall accuracy of self-reported arrests during a three-month recall period was 84.7%. Validity was higher among individuals who at the time of the follow-up interview were either in a jail diversion program or incarcerated. Individuals with a mood disorder appeared to be somewhat less accurate in their self-reports than subjects with schizophrenia, despite the implication of cognitive distortion accompanying this latter diagnostic category. Further research on issues such as the accuracy of self-reports over longer recall periods, or the accuracy of self-reported frequency of arrest, is necessary, given the reliance on self-report methodology in outcome studies.

Adult↗
PubMed2001

A double-blind, multicentered study comparing the accuracy of diagnostic markers to predict short- and long-term clinical events and their utility in patients presenting with chest pain.

BACKGROUND: Millions of patients present annually with chest pain, but only 10% have myocardial infarction (MI). We recently reported comparative sensitivity and specificity of available markers in the diagnosis of MI; however, optimum interpretation of marker results requires prognostic follow-up data. HYPOTHESIS: The study was undertaken to study the accuracy of CK-MB subforms, troponin I and T, myoglobin, and CK-MB in predicting clinical events at 30 days and 6 months. METHODS: In all, 955 consecutive patients with chest pain were enrolled in a prospective, multicenter, double-blind study to test the prognostic accuracy of these markers. RESULTS: Myocardial infarction was diagnosed in 119 by CK-MB mass criteria and unstable angina (UA) in 203 patients by clinical criteria. Follow-up at 30 days and 6 months was available in 824 and 724 patients, respectively, with mortalities of 2.8 and 4.14%, respectively. Cumulative 6-month mortality was 5.6% in MI, 4.4% in UA, and 3.0% in others. Revascularization was reported in 9.3% of patients by 6 months. A positive test on each of the markers except myoglobin was predictive of revascularization. The composite endpoint of death or revascularization occurred in 107 patients by 6 months and a positive result on each of the markers was predictive of this composite endpoint (p < 0.05). The relative risk of death or revascularization for patients who did not have MI but tested positive on each of the markers was > 1.0 but did not reach statistical significance. CONCLUSIONS: With the possible exception of myoglobin, each of the diagnostic markers displayed similar prognostic performance in patients with chest pain presenting to emergency departments. The most appropriate markers to triage patients with chest pain, which has both adequate early diagnostic sensitivity and prognostic accuracy, are the CK-MB subforms.

Adult↗
PubMed2005

Reclassification of patients with pT3 and pT4 renal cell carcinoma improves prognostic accuracy.

BACKGROUND: The significance of adrenal invasion and tumor thrombus in renal cell carcinoma (RCC) has been debated recently. The authors evaluated the associations of direct adrenal invasion, perinephric fat invasion, and tumor thrombus level with outcome to determine whether reclassification would improve the prognostic accuracy of the current primary tumor classification. METHODS: The authors studied 697 patients treated with nephrectomy for pT3 and pT4 RCC between 1970 and 2000. Associations with outcome were evaluated using Cox proportional hazards regression and prognostic accuracy was measured using the c index. RESULTS: Among patients with pT3 RCC, direct adrenal invasion was significantly associated with death from RCC (risk ratio, 2.11; P = 0.004). No significant difference in survival was found between patients with pT4 RCC and pT3 tumors with direct adrenal invasion (P = 0.490). Among patients with pT3b RCC, those with level I-III tumor thrombus were significantly more likely to die of RCC compared with patients harboring level 0 tumor thrombus (risk ratio, 1.62; P < 0.001). In addition, patients with fat invasion were more likely to die of RCC compared with pT3 patients without fat invasion (risk ratio, 1.87; P < 0.001). Therefore, patients with pT3 RCC were reclassified into 4 prognostic groups, and this reclassification significantly improved prediction of death from RCC compared with the current classification (c indices of 0.61 vs. 0.55, respectively). CONCLUSIONS: Direct adrenal invasion from RCC should be reclassified as pT4. In addition, the proposed reclassification for patients with pT3 RCC improved prognostic accuracy.

Adrenal Gland Neoplasms↗
PubMed2005

Determining the geometry of hydrogen bonds in solids with picometer accuracy by quantum-chemical calculations and NMR spectroscopy.

The structure of multiply hydrogen-bonded systems is determined with picometer accuracy by a combined solid-state NMR and quantum-chemical approach. On the experimental side, advanced 1H-15N dipolar recoupling NMR techniques are capable of providing proton-nitrogen distances of up to about 250 pm with an accuracy level of +/-1 pm for short distances (i.e., around 100 pm) and +/-5 pm for longer ones (i.e., 180 to 250 pm). The experiments were performed under fast magic-angle spinning, which ensures sufficient dipolar decoupling and spectral resolution of the 1H resonance lines. On the quantum-chemical side, the structures of the hydrogen-bonded systems were computationally optimised, yielding complete sets of nitrogen-proton and proton-proton distances, which are essential for correctly interpreting the experimental NMR data. In this way, nitrogen-proton distances were determined with picometer accuracy, so that vibrational averaging effects on dipole-dipole couplings need to be considered. The obtained structures were finally confirmed by the complete agreement of computed and experimental 'H and '5N chemical shifts. This demonstrates that solid-state NMR and quantum-chemical methods ideally complement each other and, in a combined manner, represent a powerful approach for reliable, high-precision structure determination whenever scattering techniques are inapplicable.

Chemistry, Physical↗
PubMed1990

Diagnosis of squamous-cell carcinoma of the lung by sputum cytology: with special reference to correlation of diagnostic accuracy with size and proximal extent of resected tumor.

Sputum cytology was performed in 179 cases of squamous-cell carcinoma of the lung; 134 cases were diagnosed as positive. There were no significant differences in diagnostic accuracy of sputum cytology between tumors sizes. In cases with tumors extending proximally into the main, lobar, or segmental bronchi, the diagnostic accuracy of sputum cytology was significantly higher than in cases where the proximal invasion of tumor was limited to the peripheral bronchi. In cases with tumors 3 cm or less in diameter, when tumors extended proximally into main, lobar, or segmental bronchi, the diagnostic accuracy of sputum cytology was significantly higher than in cases with tumors extending proximally into subsegmental or subsubsegmental bronchi. In peripherally located squamous-cell carcinoma, in cases in which the tumor arose in subsegmental or subsubsegmental bronchi, carcinoma could be detected by sputum cytology even when it was roentgenographically occult.

Carcinoma, Squamous Cell↗
PubMed1992

Accuracy of diagnosis of malignant lymphoma by combining fine-needle aspiration cytomorphology with immunocytochemistry and in selected cases, Southern blotting of aspirated cells: a tissue-controlled study of 86 patients.

Fine-needle aspiration (FNA) cytology of lymph nodes in malignant lymphoma is fraught with difficulty. In certain clinical situations, cytology has been documented to be useful in patients with malignant lymphoma. The intent of our investigation was to determine the accuracy of a multiparameter approach in diagnosing lymphoma. We reviewed the results of FNA cytology combined with the immunocytochemistry and, in some cases, the Southern blots of aspirated cell suspensions obtained from 86 suspected lymphoma patients who subsequently underwent surgical biopsy of the aspirated site. In four cases, in which FNA was unable to retrieve sufficient material for diagnosis, the histology showed extensive fibrosis. When the FNA diagnoses were compared with the histologic diagnoses, the diagnosis concurred in 69 cases (56 malignant lymphomas, 12 reactive, 1 atypical lymphoid proliferation). There was one false-positive, six false-negatives, and eight cases diagnosed as atypical lymphoid proliferation. Overall accuracy was 91%. There were two types of false-negative cases: those in which a diagnosis of another malignancy or unspecified malignant neoplasm was made and those that were diagnosed as reactive when the histology showed lymphoma. In seven cases, the DNA rearrangement studies of the antigen receptor genes were successfully performed on the aspirated cells and were useful in establishing lineage and clonality of both B and T lymphoid cells. Our study indicated that the use of a multiparameter approach in the diagnosis of malignant lymphoma by FNA enhanced the accuracy of diagnosis of the non-Hodgkin's lymphomas. In Hodgkin's disease, no benefit was derived from the approach.

Biopsy, Needle↗
PubMed2005

Accuracy of reported weight and menstrual status in teenage girls with eating disorders.

OBJECTIVE: The current study investigated the accuracy of reported current and historical weights and of menstrual status in teenage girls with eating disorders. METHOD: Reported current weight in one interview was compared with measured weight at another occasion. Reported historical weights were compared with documented weights from growth charts of the school health services. Reports of menstrual status from two different interviews were compared. RESULTS: The overall correlation between reported and measured/documented weight was high. Current weight was reported with high accuracy in all diagnostic groups and without tendencies to underreport. Patients with bulimia nervosa, but not those with anorexia nervosa, underreported their historical top weight. The most common reason for large discrepancies between reported and documented historical weights was that the two weights compared referred to different time points. The reports on menstrual status were divergent for 13% of the patients, most notably 4 of 15 patients on oral contraceptives had been categorized as having menstruations in one of the interviews. CONCLUSION: Reported weight history and menstrual status are of high accuracy in teenage girls with eating disorders.

Adolescent↗
PubMed2007

Use of integrated 18F-FDG PET/CT to improve the accuracy of initial cervical nodal evaluation in patients with head and neck squamous cell carcinoma.

BACKGROUND: We investigated the accuracy of performing cervical nodal evaluation with using integrated (18)F-fluoro deoxyglucose positron emission tomography (PET)/CT for squamous cell carcinoma (SCC) of the head and neck as compared with using PET and contrast-enhanced CT (CECT) alone. METHODS: The presence of metastatic lymphadenopathy in each cervical nodal group (level I-VI) and the nodal (N) classification of 47 patients with SCC of the head and neck were determined by using PET, CECT, and PET/CT, respectively, and the results were verified according to the histopathologic findings. RESULTS: Among the 91 foci that had abnormal uptake on PET, the combined PET/CT images provided additional information over PET for the anatomical localization and lesion characterization of 18 sites (19.8%) in 17 patients (36.2%). PET/CT also showed the best results among the three imaging modalities for the sensitivity, specificity, and accuracy (91.8, 98.9, and 97.1%, respectively) for predicting metastatic nodes on a level-by-level analysis, and PET/CT had a higher accuracy (85.1%) for the pathologic nodal classification over the clinical examinations (68.1%) or PET (70.2%). CONCLUSIONS: Combined PET/CT images are more accurate than the PET or CECT images alone for conducting cervical node evaluation in the patients suffering with head and neck SCC.

Aged↗
PubMed2006

Accuracy of liver stiffness measurement for the diagnosis of cirrhosis in patients with chronic liver diseases.

A proper diagnosis of cirrhosis is essential for the management of patients with chronic liver diseases. We assessed the accuracy of liver stiffness measurement by Fibroscan for the diagnosis of cirrhosis in 1,257 patients with chronic liver diseases of various causes enrolled in a prospective multicenter study as well as clarified causes of discrepancies between liver histology and Fibroscan. One hundred thirty-two patients had unsuitable biopsy specimens, and 118 had unreliable liver stiffness measurements. Because 232 patients overlapped with a previous study, analysis was performed in the 775 new patients then derived in the whole population (1,007; 165 cirrhosis). Diagnostic accuracy was assessed by receiver operator curve (ROC) analysis. Liver samples were re-analyzed in case of discrepancies. The area under the ROC (AUROC) was 0.95 (95% CI, 0.93-0.96) for the diagnosis of cirrhosis in either 775 or 1,007 patients. The cutoff value with optimal diagnosis accuracy was 14.6 kPa in 1,007 patients (positive and negative predictive values, 74% and 96%) with discrepancies among the etiological groups. Eighty patients were misclassified: (1) among 45 patients without cirrhosis with liver stiffness 14.6 kPa or greater, 27 (60%) had extensive fibrosis and 10 (22%) significant perisinusoidal fibrosis; and (2) among 35 patients with cirrhosis and liver stiffness less than 14.6 kPa, 10 (29%) had a macronodular pattern and 25 (71%) either none or mild activity. In conclusion, Fibroscan is a reliable method for the diagnosis of cirrhosis in patients with chronic liver diseases, better at excluding than at predicting cirrhosis using a threshold of 14.6 kPa. False-negatives are mainly attributable to inactive or macronodular cirrhosis.

Adult↗
PubMed2002

Evidence for a relationship between daily caffeine consumption and accuracy of time estimation.

The present study examined the relationship between regular caffeine consumption and time estimation. Sixty participants (aged 18-57 years, mean 24 years) completed a 47 s time estimation exercise and questionnaires related to daily caffeine consumption and perceptions of time. We hypothesized that the effects of caffeine on time estimation would follow a U-shaped pattern such that individuals who reported moderate amounts of daily caffeine would be more accurate in their perceptions of time than would those who reported high amounts of caffeine intake or no daily caffeine consumption. Timing accuracy was computed by dividing participant-reported time by actual time (47 s). Timing accuracy followed a U-shaped curve such that those respondents who reported 'low' daily caffeine consumption (< or = 135 mg/day, n = 24) were the most accurate in their time estimates (mean= 44.2 s). Individuals who reported no caffeine (mean= 69.3 s; n= 7) or 'high' daily caffeine consumption (mean=56.2 s; >135 mg/day, n = 28) were less accurate in their time estimates [F(2, 56)= 3.34, p< 0.05]. Findings suggest that 'low' daily caffeine consumption may enhance time estimation accuracy above that of 'high' or no daily caffeine consumption.

Adolescent↗
PubMed2002

The application accuracy of the NeuroMate robot--A quantitative comparison with frameless and frame-based surgical localization systems.

The NeuroMatetrade mark robot system (Integrated Surgical Systems, Davis, CA) is a commercially available, image-guided, robotic-assisted system used for stereotactic procedures in neurosurgery. In this article, we present a quantitative comparison of the application accuracy of the NeuroMate with that of standard frame-based and frameless stereotactic techniques. The article discusses a five-way application accuracy comparison study. The variables of our comparison and their mean errors are as follows: (1) with the robot in a frame-based configuration, the RMS was 0.86 +/- 0.32 mm; (2) with the robot in the frameless configuration, the RMS was 1.95 +/- 0.44 mm; (3) in a standard stereotactic (ZD) frame-based approach, the RMS was 1.17 +/- 0.25 mm; (4) with an infrared tracking system using the frame for fiducial registration, the RMS was 1.47 +/- 0.45 mm; (5) with an infrared tracking system using screw markers for registration, the RMS was 0.68 +/- 0.26 mm. The study was performed with 2-mm sections of CT scans. These results show that the application accuracy of the frame-based NeuroMate robot is comparable to that of standard localizing systems, whether they are frame-based or infrared tracked.

Equipment Design↗