Likelihood Ratios For Negative Results Research Articles

Diahnostychna y peredbachuvana tsinnist i vidnoshennia pravdopodibnosty zminy pokaznykiv deiakykh laboratornykh syndromiv ta yikh konsteliatsii u khvorykh na tsyroz pechinky z porushenniam mineralnoi shchilnosty kistkovoi tkanyny

Diahnostychna y peredbachuvana tsinnist i vidnoshennia pravdopodibnosty zminy pokaznykiv deiakykh laboratornykh syndromiv ta yikh konsteliatsii u khvorykh na tsyroz pechinky z porushenniam mineralnoi shchilnosty kistkovoi tkanyny

Performance of Fatty Liver Index in Identifying Non-Alcoholic Fatty Liver Disease in Population Studies. A Meta-Analysis.

Background. Fatty liver index (FLI) is a non-invasive tool used to stratify the risk of non-alcoholic fatty liver disease (NAFLD) in population studies; whether it can be used to exclude or diagnose this disorder is unclear. We conducted a meta-analysis to assess the prevalence of NAFLD in each FLI class and the performance of FLI in detecting NAFLD. Methods. Four databases were searched until January 2021 (CRD42021231367). Original articles included were those reporting the performance of FLI and adopting ultrasound, computed tomography, or magnetic resonance as a reference standard. The numbers of subjects with NAFLD in FLI classes <30, 30–60, and ≥60, and the numbers of subjects classified as true/false positive/negative when adopting 30 and 60 as cut-offs were extracted. A random-effects model was used for pooling data. Results. Ten studies were included, evaluating 27,221 subjects without secondary causes of fatty liver disease. The prevalence of NAFLD in the three FLI classes was 14%, 42%, and 67%. Sensitivity, specificity, positive predictive value, negative predictive value, likelihood ratio for positive results, likelihood ratio for negative results, and diagnostic odds ratio were 81%, 65%, 53%, 84%, 2.3, 0.3, and 7.8 for the lower cut-off and 44%, 90%, 67%, 76%, 4.3, 0.6, and 7.3 for the higher cut-off, respectively. A similar performance was generally found in studies adopting ultrasound versus other imaging modalities. Conclusions. FLI showed an adequate performance in stratifying the risk of NAFLD. However, it showed only weak evidence of a discriminatory performance in excluding or diagnosing this disorder.

Predictors of vertigo in the emergency department: The preved study

Background and PurposeAcute vertigo (sense of motion) can be the sole manifestation of a posterior circulation stroke, and often gets missed in the emergency department (ED). The studies for evaluation of central vertigo have focused on physical exam findings, which require expertise and may not be suitable for rapid triage by a nurse in ED or by paramedics. MethodsThis cross sectional study included retrospective chart review of patients 18 years of age and older who presented to the Adult ED with acute dizziness or vertigo during the calendar year 2017. All the patients with a diagnosis of central or peripheral vertigo were included in the final analysis. Sensitivity, specificity, Likelihood Ratio of positive result (LR (+)) and Likelihood Ratio of negative result (LR (-)) for central and peripheral vertigo were calculated for risk factors, symptoms and physical examination features. Chi-squared test and univariate logistic regression were used to evaluate statistical correlation and to calculate the prevalence odds ratio (POR). ResultsTwo hundred and forty nine out of 505 (49.3%) patients presenting with dizziness had vertigo. Of these, 14 had central vertigo and 163 had peripheral vertigo. Statistically significant variables were: constant symptoms of vertigo (p 0.000- POR 8.7, 95% confidence interval (CI) 2.3-33.1), no change in symptoms with head movement (p 0.000- POR 10.2, 95% CI 3.0-35.4), dysmetria (p 0.000- POR 56.8, 95% CI 5.8-557.1), and unsteady gait (p 0.000- POR 13.3, 95% CI 3.3-54.3). The sensitivity and specificity to detect central vertigo were 100% and 66.4% respectively if the patient had either unsteady gait, constant symptoms, or no change in symptoms with head movement, [VAIN triad (Vertigo- Ataxia, Incessant, or Non-positional)]. ConclusionsWe suggest that triage with VAIN triad can be used to design prospective studies to develop a triage algorithm for the detection of central vertigo in the ED.

The Diagnostic Accuracy of Сoronary Сomputed Tomography Angiography in the Diagnosis of Stable Coronary Artery Disease in Patients Aged 70 Years and Older

The purpose of this study was to evaluate the diagnostic accuracy of сoronary сomputed tomography angiography (CCTA) in the diagnosis of stable coronary artery disease (CAD) in patients aged ≥70 years. The study included 390 patients aged ≥70 years with symptoms suggested stable CAD which underwent elective coronary artery angiography (CAG). Initially the prevalence of angiographically significant CAD was estimated according to the gender and chest pain character, and identifications of patients in whom CCTA was appropriate. After that diagnostic accuracy and сost-efficiency of CCTA in the diagnosis of stable CAD in 82 patients with atypical angina and non-anginal chest pain were evaluated. The prevalence of obstructive CAD in patients with typical angina was very high and they were excluded from the final analysis. Among 82 patients with atypical angina and non-anginal pain which underwent CCTA 48 (59%) patients had obstructive CAD. CСTA data matched with results of CAG in all cases. Among 34 patients that had non-obstructive CAD the results of CCTA and CAG matched in 88% cases. CCTA has sensitivity, specificity, positive predictive value, negative predictive value of 100%, 88%, 92% and 100% respectively. The likelihood ratio for positive result was 8.3, likelihood ratio for negative result was 0.3. Positive result increased post-test probabilityof obstructive CAD from 42% to 86%, negative result reduced post-test probabilityof obstructive CAD to 0%. negative CCTA result in patients aged 70 years and older with atypical angina and non-anginal pain allows to exclude the presence of obstructive CAD. The likelihood ratio for positive result indicates a moderately difference between the pre-test and post-test probability of the presence of obstructive CAD. In patients aged ≥70 years with atypical angina or non-anginal chest pain which have inconclusive results of functional testing or unable undergo functional testing CCTA allows to increase diagnostic yield of CAG and reduce the frequency of minor complications and diagnostic evaluation costs.

Screening of Extended-Spectrum β-Lactamases (ESBL)-producing Klebsiella pneumoniae with ChromID ESBL Media

BACKGROUND: Klepsiella pneumoniae, one of clinical isolates, is frequently found causative agent of hospital acquired infection. Currently, K. pneumoniae is found as extended-Spectrum β-lactamases (ESBL) producer, allowing it to become multidrugresistant. A clinical laboratory with limited facility needs a valid, reliable, inexpensive and simple laboratory test to control its infection and antimicrobial-resistancy. The aim of this study is to evaluate the diagnostic performance of a ESBL media to detect ESBL-producing K. pneumoniae.METHODS: An independent and blind comparative study of ChromID ESBL media and Double Disc Synergy Test (DDST) was conducted for detecting the clinical isolate of ESBL-producing K. pneumoniae. Clinical isolates of K. pneumoniae collected from the Clinical Laboratory of Dr. Sardjito Hospital were isolated.RESULTS: There were 103 clinical isolates of K. pneumoniae, which were isolated from urine, pus, blood, stool, cerebrospinal fluid, sputum, drain liquid, nasal sinus liquid, gastric wash, bronchi liquid, injury liquid and nasal swab. The number of true positive, true negative, false positive and false negative results were 74, 18, 9 and 2, respectively. Meanwhile, the sensitivity, specificity, positive predictive value, negative predictive value, likelihood ratio for positive result and likelihood ratio for negative result of the new ESBL media were 97.4%, 66.7%, 89.2%, 90%, 2.9 and 0.03, respectively.CONCLUSION: Since the new ESBL media and DDST results were similar, so the new ESBL media could be used for screening patients with clinical presentation that indicating a high suspicious of ESBL-producing bacteria.KEYWORDS: K. pneumoniae, ChromID ESBL, DDST, ESBL, sensitivity

Diagnostic performance of ultrasound in patients with suspected brachial plexus lesions in adults: a multicenter retrospective study with MRI, surgical findings and clinical follow-up as reference standard

To evaluate brachial plexus ultrasound (US) performance in a large multicenter study. The research was approved by the Institutional Review Boards, and all patients gave written informed consent. A multicenter retrospective trial including three centers was performed between March, 2006 and April, 2011. A total of 204 patients who received a brachial plexus ultrasound requested by the referring physician were enrolled: magnetic resonance imaging, surgical findings and clinical follow-up of at least 12 months were used as the reference standard. Sensitivity, specificity with 95 % confidence intervals (CIs), positive predictive value (PPV), pre-test-probability (the prevalence), negative predictive value (NPV), pre- and post- test odds (OR), likelihood ratio for positive results (LH+), likelihood ratio for negative results (LH-), accuracy and post-test probability (post-P) were reported on a per-patient basis. The overall sensitivity and specificity with 95 % CIs were: 0.76 (0.75-0.97); 0.96 (0.77-0.89). Overall PPV, pre-test probability, NPV, pre-OR, post-OR, LH+, LH-, Accuracy and post-P were: 0.93/0.43/0.84/0.75/0.75/13.4/17.6/0.25/0.88/0.93, respectively. The specificity of brachial plexus US in patients suspected of having a brachial plexus lesion is very high.

Diagnostic accuracy of MRI in adults with suspect brachial plexus lesions: A multicentre retrospective study with surgical findings and clinical follow-up as reference standard

ObjectiveTo evaluate brachial plexus MRI accuracy with surgical findings and clinical follow-up as reference standard in a large multicentre study. Materials and methodsThe research was approved by the Institutional Review Boards, and all patients provided their written informed consent. A multicentre retrospective trial that included three centres was performed between March 2006 and April 2011. A total of 157 patients (men/women: 81/76; age range, 18–84 years) were evaluated: surgical findings and clinical follow-up of at least 12 months were used as the reference standard. MR imaging was performed with different equipment at 1.5T and 3.0T. The patient group was divided in five subgroups: mass lesion, traumatic injury, entrapment syndromes, post-treatment evaluation, and other.Sensitivity, specificity with 95% confidence intervals (CIs), positive predictive value (PPV), pre-test-probability (the prevalence), negative predictive value (NPV), pre- and post-test odds (OR), likelihood ratio for positive results (LH+), likelihood ratio for negative results (LH−), accuracy and post-test probability (post-P) were reported on a per-patient basis. ResultsThe overall sensitivity and specificity with 95% CIs were: 0.810/0.914; (0.697–0.904). Overall PPV, pre-test probability, NPV, LH+, LH−, and accuracy: 0.823, 0.331, 0.905, 9.432, 0.210, 0.878. ConclusionsThe overall diagnostic accuracy of brachial plexus MRI calculated on a per-patient base is relatively high. The specificity of brachial plexus MRI in patients suspected of having a space-occupying mass is very high. The sensitivity is also high, but there are false-positive interpretations as well.

Neuropad as a diagnostic tool for diabetic autonomic and sensorimotor neuropathy

The aim of the present study was to determine the diagnostic accuracy of the Neuropad sudomotor test for diabetic cardiovascular autonomic neuropathy (CAN) and diabetic polyneuropathy (DPN), the latter assessed using a multi-level diagnostic approach. In 51 diabetic patients, CAN, symptoms and signs of DPN, vibration perception threshold (VPT), cold (CTT) and warm thermal perception thresholds (WTT) were measured. Neuropad response was determined as normal (complete colour change) or abnormal (absent or incomplete colour change). The time until the complete colour change (CCC time) was recorded. CCC time showed significant correlations with all the neurological parameters, the strongest of which were with Valsalva ratio (rho = -0.64, P < 0.0001), symptoms of DPN (rho = 0.66, P < 0.0001), postural hypotension (rho = 0.54, P = 0.0001) and CTT (rho = -0.54, P = 0.0001). CCC time showed moderate diagnostic accuracy for both CAN and DPN: the areas under the receiver operating characteristic (ROC) curves were 0.71 and 0.76, respectively. The diagnostic characteristics of three cut-off values of CCC time, identified by ROC analysis (i.e. 10, 15 and 18 min), were analysed. Compared with 10 min, the 15-min cut-off value provided better specificity (from 27% to 52% and from 31% to 62% for CAN and DPN, respectively) and a better likelihood ratio for negative result (from 0.67 to 0.34 and from 0.58 to 0.33) without lowering sensitivity (from 82% to 82% and from 85% to 80%). Neuropad is a reliable diagnostic tool for both CAN and DPN, albeit of only moderate accuracy. Extending the observation period to 15 min provides greater diagnostic usefulness.

A rapid immunochromatographic assay for the detection of Mycobacterium tuberculosis antigens in pulmonary samples from HIV seropositive patients and its comparison with conventional methods

As tuberculosis generates a highly heterogeneous antibody repertoire, its diagnosis requires tests based on cocktails of antigens. We describe a new, rapid method called rapid immunochromatographic assay (RICA) for cocktail-based diagnosis, which can detect Mycobacterial antigens in sputum specimens. Six antigenic fractions of pathogenic Mycobacterium tuberculosis were used in combination as the capture antigens in the control line of the flow-through assay. Antigen detection of 200 sputum samples from HIV seropositive patients by RICA assay gave a sensitivity of 97.9%, specificity of 99.0%, positive predictive value of 98.9%, negative predictive value of 98.0%, false positive rate of 0.9%, false negative rate of 2.0%, prevalence rate of 49%, likelihood ratio for positive results 97 and likelihood ratio for negative results 0.02. The combination of RICA and AFB staining gave a sensitivity of 100%, specificity of 100%, positive predictive value of 100%, negative predictive value of 100%, false positive rate of 0%, false negative rate of 0%, likelihood ratio for negative results 0. The assay was simple, rapid and economical for the detection of M. tuberculosis infection and suitable for large scale screening of samples in endemic areas without any sophisticated equipment. The results of the assay proved to be superior to conventional methods and combined with clinical data, could form the basis for starting an earlier course of treatment.

P0990 CORRELATION OF ABDOMINAL ULTRASONOGRAPHIC FINDINGS WITH 24-HOUR OESOPHAGEAL PH MONITORING IN GASTROESOPHAGEAL REFLUX DISEASE (GORD)

Introduction: To determine the value of abdominal ultra-sonography (US) as a screening tool for children with significant gastroesphageal reflux (GOR) compared to 24-hour pH studies. Methods: A retrospective evaluation of data from children presenting with symptoms suggestive of GOR at Queen Mary’s Hospital for Children in the United Kingdom between the years of 1999 and 2003 was collected. All patients who underwent an abdominal ultrasound scan (with comments on gasrtroesphageal junction and reflux) and continuous 24-hour pH monitoring were included in the study. pH positive GOR was based on the finding of a percent fraction time pH less than 4 [Reflux Index (RI)], of more than 10% in children below one year of age and a RI of more than 5% onwards. The criteria for ultrasound scan positive GOR were based on recording the number of reflux episodes during the scanning period, spontaneous widening of gastroesphageal junction, demonstration of gastric contents entering the oesophagus or the occurrence of free gastroesphageal reflux. DeMeester score is a scoring system incorporating several parameters to calculate the degree to which the patient’s reflux pattern differs from the norm. [Normal <15]. Results: The average age was 3.7 years (range 2 months-11 years). There were sixteen males and fifteen females. Fifteen patients were positive for both RI and US scans and 8 patients had both normal RI and normal US scan. Seven patients who had normal RI had mild gastroesphageal reflux on U/S, but had slightly elevated DeMeester scores. One patient had abnormal RI but this was not detected by US. When the Reflux Index was taken as the reference value, US had a sensitivity of 93 % for diagnosing significant reflux and a specificity of 53 %. The Likelihood Ratio (LR) for positive test results was 2 and LR for negative results was 0.11. Conclusion: Abdominal Ultrasonography may be a useful non-invasive screening method for detection of GOR in infants and children. Our study shows a statistically significant relationship between the ultrasonographic findings detected, the RI and the DeMeester scores. Prospective studies will need to be performed to correlate the grade of US detected reflux, gastroesphageal junction variations and the RI.

Prediction of successful induction of labor at term: role of clinical history, digital examination, ultrasound assessment of the cervix, and fetal fibronectin assay

Objective The purpose of this study was to evaluate whether biochemical (fetal fibronectin assay) or biophysical (cervical assessment by transvaginal ultrasound) tests may have more value than digital examination in predicting successful induction of labor at term. Study design The study enrolled prospectively 134 women undergoing labor induction at term caused by several obstetric conditions. All participants submitted to digital examination, fetal fibronectin assay, and transvaginal ultrasound for measurement of the cervical length and detection of funneling. The performance of each test in predicting delivery within 24 hours of labor induction was evaluated. Cox multiple regression analysis was performed to identify, among clinical and laboratory tests, which variables were independently associated with the duration of the latent phase and with the total duration of induced labor. Results The likelihood ratios for positive results (predicting that delivery would occur within 24 hours) were 6.61 (95% CI, 1.7-25.8) for a positive obstetric history (previous vaginal delivery), 2.61 (95% CI, 1.6-4.3) for a “favorable” digital examination, 1.41 (95% CI, 0.9-2.2) for a positive fetal fibronectin test, 1.61 (95% CI, 0.9-3.0) for cervical length, and 2.20 (95% CI, 1.1-4.4) for the presence of funneling at transvaginal ultrasound. The likelihood ratios for negative results were 1.81 (1.3-2.5) for obstetric history, 4.34 (2.5-7.7) for digital examination, 1.41 (0.9-2.1) for fetal fibronectin, 1.29 (1.0-1.7) for cervical length, and 1.48 (1.1-2.0) for funneling. On multiple regression, the only variables independently associated with the duration of the latent phase and with the total duration of induced labor were obstetric history and digital examination. Conclusion Only obstetric history and digital examination predicted accurately vaginal delivery within 24 hours and were independently associated with labor duration. Fetal fibronectin and ultrasound measurements failed to predict accurately the outcome of induced labor.

Accuracy of cervicovaginal fetal fibronectin test in predicting risk of spontaneous preterm birth: systematic review

abstractObjective: To determine the accuracy with which a cervicovaginal fetal fibronectin test predicts spontaneous preterm birth in women with or without symptoms of preterm labour.Design: Systematic quantitative review of studies...

The Role of Hepatic Arterial Doppler Ultrasound after Liver Transplantation: an ‘Audit Cycle’ Evaluation

AIMS: To compare the diagnostic performance of hepatic arterial (HA) Doppler ultrasound post-liver transplantation for hepatic artery thrombosis and stenosis in our unit with the literature. To evaluate the role of the technique in clinical practice.MATERIALS AND METHODS: In a two-phase ‘audit cycle’ study, adult OLT patients had Doppler studies comprising detection of HA flow and measurements of peak systolic velocity, resistive index and systolic acceleration time. In phase I, patients had Doppler examinations ‘routinely’ and for any hepatic biochemical abnormality. In phase II, Doppler ultrasound was performed early post-OLT and later only if a senior transplant clinician suspected graft ischaemia. In addition to HA measurements the waveform was visually assessed. Clinical outcome was the ‘gold standard’.RESULTS: Phase 1: 38 patients, 40 OLT operations, 125 Doppler studies; 14 arteriograms. Phase 2: 35 patients, 42 OLT operations, two HA angioplasties, one HA revision, one non-occlusive thrombus, 140 studies; 17 arteriograms. Results; Phase 1 [Phase 2]: sensitivity 80% [100%]; specificity 71% [81%]; PPV 28% [56%]; NPV 96% [100%]; incidence of HA abnormality 12.5% [19.5%]; likelihood ratio of negative result 0.28 [0]; of positive result 2.8 [5.3].CONCLUSION: Previously reported results are reproducible. Normal HA waveform should also be a criterion of normality. The technique is very sensitive but relatively non-specific. Predictive values improve with discriminate use.MacEneaney, P. M. (2000). Clinical Radiology55, 517–524.

Abstracts of Literature.

Abstracts of Literature.

Role of Transcranial Doppler Monitoring in the Diagnosis of Cerebral Vasospasm after Subarachnoid Hemorrhage

OBJECTIVE: The purpose of this study was to determine the correlation between transcranial Doppler (TCD) velocities and angiographic vasospasm after aneurysmal subarachnoid hemorrhage. METHODS: In the first part of this study, patients were retrospectively reviewed to correlate middle cerebral artery absolute blood flow velocities with angiographic vasospasm. In the second part of the study, the middle cerebral artery/ipsilateral extracranial internal carotid artery velocity ratio (Lindegaard ratio) was prospectively correlated with angiographic vasospasm. Angiographic vasospasm was independently graded, by observers blinded to the TCD results, as either none, mild (less than one-third artery luminal narrowing), moderate (one-third to one-half narrowing), or severe (more than one-half narrowing). The sensitivity, specificity, likelihood ratios for positive and negative TCD results, positive and negative predictive values, and kappa and P values were calculated. RESULTS: One hundred one patients were analyzed in the first part of the study, and 44 patients were analyzed in the second part. Interobserver agreement regarding angiographic vasospasm was good (kappa = 0.86). Despite significant correlation between mean velocities and the degree of vasospasm, the clinical dependability of TCD velocities (evaluated using predictive values and likelihood ratios) was limited. The positive predictive value of velocities of > or =200 cm/s for moderate/severe angiographic vasospasm was 87% but that of lower velocities was approximately 50%. The negative predictive value of velocities of <120 cm/s was 94% but that of higher velocities was approximately 75%. Only the likelihood ratios for velocities of <120 or > or =200 cm/s were useful (likelihood ratio for negative result = 0.17, likelihood ratio for positive result = 16.39). Overall, 57% of patients exhibited maximum velocities in the indeterminate range between 120 and 199 cm/s. Lindegaard ratios did not improve the predictive value of TCD monitoring. CONCLUSION: For individual patients, only low or very high middle cerebral artery flow velocities (i.e., <120 or > or =200 cm/s) reliably predicted the absence or presence of clinically significant angiographic vasospasm. Intermediate velocities, which were observed for approximately one-half of the patients, were not dependable and should be interpreted with caution.