Rate Of False-positive Diagnoses Research Articles

Sensitivity, positive predictive value, and interobserver variability of computed tomography in the diagnosis of bullae associated with spontaneous pneumothorax in dogs: 19 cases (2003–2012)

To determine the sensitivity, positive predictive value, and interobserver variability of CT in the detection of bullae associated with spontaneous pneumothorax in dogs. Retrospective case series. 19 dogs with spontaneous pneumothorax caused by rupture of bullae. Dogs that had CT for spontaneous pneumothorax caused by rupture of bullae confirmed at surgery (median sternotomy) or necropsy were included. Patient signalment, CT protocols, and bulla location, size, and number were obtained from the medical records. Computed tomographic images were reviewed by 3 board-certified radiologists who reported on the location, size, and number of bullae as well as the subjective severity of pneumothorax. Sensitivities of the 3 readers for bulla detection were 42.3%, 57.7%, and 57.7%, with positive predictive values of 52.4%, 14.2%, and 8.4%, respectively, with the latter 2 readers having a high rate of false-positive diagnoses. There was good interobserver agreement (κ = 0.640) for correct identification of bullae. Increasing size of the bulla was significantly associated with a correct CT diagnosis in 1 reader but not in the other 2 readers. Correct diagnosis was not associated with slice thickness, ventilation protocol, or degree of pneumothorax. Sensitivity and positive predictive value of CT for bulla detection were low. Results suggested that CT is potentially an ineffective preoperative diagnostic technique in dogs with spontaneous pneumothorax caused by bulla rupture because lesions can be missed or incorrectly diagnosed. Bulla size may affect visibility on CT.

Monitoring young people with type 1 diabetes for diabetic nephropathy: Potential errors of annual ACR testing

AimType 1 diabetes guidelines recommend annual monitoring of albumin-creatinine ratio (ACR) to detect nephropathy. Annual monitoring for conditions such as dyslipidemia leads to high rates of false-positive diagnoses. We estimated rates of false-positive and false-negative diagnoses under annual, biennial and triennial monitoring. MethodsUsing Oxford Regional Prospective Study (ORPS) data we modelled ACR over time. Using simulation we estimated numbers of positive and negative diagnoses and the proportion that are false, over 6 years of monitoring, when assessment intervals are 1, 2 or 3 years. ResultsAverage increase per year (95%C.I.) in ACR was 3,5% (2,0–5,0%) for males and 4,8% (3,2–6,5%) for females. By 6 years, annual monitoring would lead to 56 (49–63) false-positive diagnoses for every 100 positive diagnoses of micro-albuminuria, biennial to 49 (42–57) false-positives and triennial to 46 (39–53). For every 100 negative diagnoses, annual monitoring would lead to 1,2 (0,8–1,5) false-negatives, biennial to 2,3 (1,7–3,0) and triennial to 3,0 (2,2–3,8). ConclusionLess frequent monitoring would result in fewer false-positive diagnoses, but increased false negatives, or missed diagnoses. The clinical implications of these scenarios need further investigation through cost-benefit analysis.

How Predictive are the Signs and Symptoms of Small Bowel Obstruction

The present study aims to determine the diagnostic significance of signs and symptoms of Small Bowel Obstruction (SBO) and to ascertain if there was any delay in presentation of the patients to the hospital. This retrospective case study spanning 3 years was conducted at Riyadh Medical Complex, Saudi Arabia. All adult patients admitted from the ER with a diagnosis of SBO were included in the study. The medical records of the patients with International Classification of Diseases (ICD) 9 codes 552.8, 560, 560.8, 560.81 and 560.9 were searched and retrieved. A total of 195 patients were included in the study out of which 174 patients had a definitive diagnosis of SBO. The study group was composed of 76.4% males and 71.8% were aged between 20 years to 60 years. The mean duration of symptoms was 4.8 days, ranging from 6 hours to 17 days. The cardinal signs and symptoms of obstruction had low sensitivity (Range: 56-75), and specificity (Range: 28-61), but relatively high positive predictive value (PPV) (Range: 86-93). The morbidity was 13.8% while mortality was 3.4%. The cardinal features of SBO are neither specific nor sensitive, and though they may have an acceptable PPV, the predicted rate of false positive diagnosis is unacceptable. Therefore, the clinician may not rely on the clinical picture alone for the diagnosis of SBO. The presentation of the studied patients was delayed compared to the literature and it may be an important factor in increasing morbidity and mortality, but this aspect needs to be studied further.

Evaluation of selection criteria for validating paired umbilical cord blood gas samples: an observational study

To compare six validation criteria for umbilical cord blood gas (UCBG) values in vigorous and nonvigorous neonates. Retrospective cohort study. Single tertiary obstetric centre, King Edward Memorial Hospital (KEMH), Perth, Western Australia. A total of 37,763 consecutive deliveries at >23 weeks of gestation. Six validation criteria were compared to evaluate the proportion of deliveries with 'valid' UCBG data; and the proportion of vigorous and nonvigorous neonates with metabolic acidaemia. Proportion of deliveries with 'valid' UCBG values; proportions of vigorous and nonvigorous neonates with normal, borderline and abnormal UCBG values. The criteria based on KEMH 5th centile arteriovenous pH and Pco(2) differences resulted in a higher proportion of neonates with 'valid' UCBG values than the previously described Westgate and Kro criteria. The increase in 'valid' UCBG values occurred across the entire study population including vigorous and nonvigorous neonates. Among neonates with short-term neonatal complications there was an increase in nonvigorous neonates with umbilical artery metabolic acidaemia. There was no corresponding increase in vigorous neonates diagnosed with abnormal UCBG values. Use of the KEMH criteria results in an increase in the proportion of nonvigorous term neonates with UCBG data considered 'valid' to aid clinicians in the management of the neonate shortly after delivery. This change occurs without increasing the rate of false-positive diagnoses of acidaemia in vigorous neonates. The KEMH 'validation' criteria were developed from an entire presenting population and provide a simple algorithm that can be universally applied to identify neonates with nonphysiological UCBG values.

Effects of fluorescent light‐guided transurethral resection on non‐muscle‐invasive bladder cancer: a systematic review and meta‐analysis

What's known on the subject? and What does the study add? It was well known that FL-guided TURBT could reduce the residual rate of NMIBC, but our systematic review suggested that it was not superior to conventional WL-guided TURBT in diagnostic accuracy and it had no significant effect on short-term RFS and PFS. To assess the diagnostic accuracy and therapeutic outcomes of fluorescent light (FL)-guided transurethral resection (TUR) in non-muscle-invasive bladder cancer (NMIBC). A systematic search of PUBMED, EMBASE and Cochrane Library was performed to identify randomized controlled trials comparing the outcomes of FL- and white-light (WL)-guided TUR of bladder tumours (TURBT). Outcomes included tumour detection rate, false-positive diagnosis rate, carcinoma in situ (CIS) detection rate, residual tumour rate, recurrence-free survival (RFS) and progression-free survival (PFS). RevMan 5.1 software was used for the meta-analysis. Data from 14 studies, involving 4078 patients with suspected or proven NMIBC, were pooled and included in the meta-analysis. There was no significant difference in tumour detection rate (relative risk [RR] 0.99; 95% confidence interval [CI] 0.96-1.03; P = 0.64) and CIS detection rate (RR 0.82; 95% CI 0.67-1.02; P = 0.07) between the FL and the WL groups. The false-positive diagnosis rate of the FL group was higher than that of the WL group (RR 0.69; 95% CI 0.49-0.97; P = 0.03). The tumour residual rate was higher in the WL group than in the FL group (RR 2.77; 95% CI 1.47-5.02; P = 0.002). No significant differences were found between groups at 3-month follow-up (RR 1.15; 95% CI 0.79-1.66; P = 0.46) or 12-month follow-up (RR 0.86; 95% CI 0.70-1.06; P = 0.16) or in terms of either RFS or PFS at 12-month (RR 0.99; 95% CI 0.94-1.04; P = 0.57) and 24-month follow-up (RR 1.02; 95% CI 0.98-1.06; P = 0.35). FL-guided TURBT was not superior to conventional WL in diagnostic accuracy. Although FL-guided TURBT had an advantage in reducing the residual tumour rate, it had no significant effect on short-term RFS and PFS.

Diagnostic criteria of amyotrophic lateral sclerosis (ALS)

The revised El Escorial Criteria (EEC) are the gold standard of ALS diagnosis. They are very specific although insensitive and not suitable for early diagnosis. Therefore the Awaji Criteria have been developed which put more emphasis on EMG findings than the EEC, especially on fasciculation potentials. The Awaji Criteria regard fasciculation potentials as sign of active denervation in an otherwise typical clinical context of ALS. Recent publications confirm that the Awaji Criteria have a higher sensitivity than the EEC in the diagnosis of ALS without increasing the rate of false positive diagnoses.

Granulomatous Inflammation—An Underestimated Cause of False-Positive Diagnoses in Lung Fine-Needle Aspirates: Observations From the College of American Pathologists Nongynecologic Cytopathology Interlaboratory Comparison Program

The false-positive rate for fine-needle aspirates of the lung has been cited as less than 1% for granulomatous inflammation, comprising one of the known causes of false-positive diagnoses. To determine the rate of false-positive diagnoses of granulomatous inflammation for lung fine-needle aspirates by assessing the false-positive response rate in the context of the College of American Pathologists Nongynecologic Cytopathology Interlaboratory Comparison Program. We performed a retrospective review of 1092 participant responses for lung fine-needle aspirate challenges with the reference diagnosis of specific infections/granulomatous inflammation from 1998 to 2008 from the College of American Pathologists Nongynecologic Cytopathology Interlaboratory Comparison Program. False-positive rates by participant type (pathologist versus cytotechnologist), general diagnosis category, reference diagnosis, and preparation type were analyzed for the pathologists' responses. Of the 502 general category responses for pathologists, 428 (85.3%) were benign, 55 (11%) were malignant, and 19 (3.8%) were suspicious. There was no difference in the false-positive rate between preparations (P = .76) or participants (P = .39). Of those responses by pathologists that were benign, only 68.7% (292 of 425) were an exact match to granulomatous inflammation. Non-small cell carcinoma, adenocarcinoma, and squamous carcinoma represented 64% of false-positive/suspicious responses, while small cell carcinoma and carcinoid comprised 13%. In an interlaboratory comparison program, granulomatous inflammation represents an important cause of false-positive/suspicious responses in lung fine-needle aspirates (14.8%) and is much higher than false-positive rates reported historically in clinical studies. These results highlight the importance of granulomatous inflammation as a mimic of carcinoma.

The Danish Randomized Lung Cancer CT Screening Trial—Overall Design and Results of the Prevalence Round

Lung cancer screening with low dose computed tomography (CT) has not yet been evaluated in randomized clinical trials, although several are underway. In The Danish Lung Cancer Screening Trial, 4104 smokers and previous smokers from 2004 to 2006 were randomized to either screening with annual low dose CT scans for 5 years or no screening. A history of cigarette smoking of at least 20 pack years was required. All participants have annual lung function tests, and questionnaires regarding health status, psychosocial consequences of screening, smoking habits, and smoking cessation. Baseline CT scans were performed in 2052 participants. Pulmonary nodules were classified according to size and morphology: (1) Nodules smaller than 5 mm and calcified (benign) nodules were tabulated, (2) Noncalcified nodules between 5 and 15 mm were rescanned after 3 months. If the nodule increased in size or was larger than 15 mm the participant was referred for diagnostic workup. At baseline 179 persons showed noncalcified nodules larger than 5 mm, and most were rescanned after 3 months: The rate of false-positive diagnoses was 7.9%, and 17 individuals (0.8%) turned out to have lung cancer. Ten of these had stage I disease. Eleven of 17 lung cancers at baseline were treated surgically, eight of these by video assisted thoracic surgery resection. Screening may facilitate minimal invasive treatment and can be performed with a relatively low rate of false-positive screen results compared with previous studies on lung cancer screening.

Malaria overdiagnosis and burden of malaria misdiagnosis in the suburbs of central Sudan: special emphasis on artemisinin-based combination therapy era

Accuracy of diagnosis is central for malaria control. Although microscopy is gold standard in malaria diagnosis, its reliability is largely dependent on user skill. In this study, we evaluated practitioners' clinical and microscopists' technical skills in diagnosis of malaria in central Sudan. In a retrospective study, 3203 blood smears from 95 peripheral health facilities (each represented by a general practitioner [GP] and general microscopist [GM]) were reexamined by expert microscopist. Furthermore, in a prospective study, 410 patients had their malaria diagnosis rechecked by rapid diagnostic test for validation of the microscopic diagnosis. Results showed that the rate of false-positive diagnosis of malaria was 75.6% and false-negative diagnosis was 0.01%. The study disclosed poor skills of the GPs and GMs in malaria diagnosis because 43% of the GPs and 44% of the GMs failed to make a single true-positive malaria diagnosis. The false-positive malaria diagnosis showed bias toward adult females. Economically, the calculated cost of diagnosis and treatment of malaria in Sudan in year 2000 is US$100 million, whereas the calculated cost of true malaria is approximately US$14 million. In conclusion, malaria overdiagnosis was widely recognized in central Sudan, with high economic burden during the era of artemisinin-based combination therapy. Finally, different scenarios were suggested for improvement of malaria diagnosis.

False-positive and false-negative cases of fine-needle aspiration cytology for palpable breast lesions

Fine-needle aspiration cytology (FNA) is less traumatic and technically easy to apply to small breast tumors. A total of 382 cases of palpable breast lesions that had undergone fine needle aspiration and histopathologic diagnosis were reviewed with an emphasis on the rate of false positive diagnoses in benign breast lesions. A diagnosis of " malignant " was made in 98 of the 382 specimens (25.6%). The predictive value for malignancy was 97.9%. The sensitivity, specificity, and accuracy of FNA were 86.3%, 98.2%, and 93.2%, respectively, when the " suspicious " group was considered positive for malignancy. The histologic subtypes of the 4 false-positive cases were epithelial proliferative lesions, ductal or lobular hyperplasia. None of these 4 cases were definitely diagnosed as " malignant " by radiological studies. Four false-negative cases by FNA were suspicious for malignancy radiologically. There was no specific pathological subtype associated with false-negative status on FNA in this study. Palpable breast tumors can be definitively diagnosed based on a combination of physical examination, radiological studies and FNA, when the radiological studies concur with the diagnosis by FNA.

Epidemiologic features, seasonal variations and false positive rate of acute appendicitis in Shahr-e-Rey, Tehran

Introduction Appendicitis is the most common acute surgical condition of the abdomen. Age, sex and seasonal variations have been observed in many studies. To describe and find the possible differences in the epidemiology of acute appendicitis in Shahr-e-Rey, we carried out a retrospective study of all patients with acute appendicitis admitted to Shohadaay-e Haftom-e Tir hospital as it is the only hospital in this restricted part of Tehran. Methods Using hospital discharge abstract of patients who were admitted with the diagnosis of acute appendicitis from summer 1996 to spring 2004, we studied the demographic features, particularly age and sex, date of admission and final diagnosis of these patients. Results During the observation period, 1093 cases were admitted with the diagnosis of acute appendicitis. Of these, 74.4% were males and 6.1% were not actually an acute appendicitis. The age-specific incidence of acute appendicitis has different patterns in male and female. The incidence was highest in males aged 20–29 years whereas in females the highest incidence was observed in 10–19 years age group. A significant seasonal effect was also observed, with the rate of acute appendicitis higher in the summer months ( p < 0.006). The rate of false positive diagnosis was highest in the patients aged 0–9 years ( p < 0.0001). Of those correctly diagnosed, 85.5% had uncomplicated acute appendicitis; 8.3% had perforation; and others (6.2%) had acute appendicitis complicated with other situations. Conclusion Appendicitis is more common in males, in those aged 20–29 years, and during the summer months. The age-specific incidence and sex ratio of acute appendicitis give the impression that epidemiologic features of acute appendicitis are different with worldwide data. However, the seasonal variation and false positive rate of acute appendicitis are in a good agreement with other studies.

Impact of reliance on CT pulmonary angiography on diagnosis of pulmonary embolism: A Bayesian analysis

Spiral computed tomographic pulmonary angiography (CTPA) has become the primary test used to investigate suspected pulmonary embolism (PE) at many institutions, despite uncertainty regarding its sensitivity and specificity. Although CTPA-based diagnostic algorithms focus on minimizing the false-negative rate, we hypothesized that increasing use of CTPA also might lead to false-positive diagnoses. Determine the frequency of possible false-positive diagnoses of PE when CTPA is the primary diagnostic test. Retrospective cohort study. Two academic teaching hospitals. 322 patients with suspected PE evaluated with CTPA. We used a validated prediction rule to determine the pretest probability of PE in each patient. We combined these pretest probabilities with published estimates of CTPA test characteristics to generate expected posttest probabilities of PE. We compared these posttest probabilities to actual treatment decisions to determine the rate of false-positive diagnoses of PE. Among 322 patients investigated for PE, 37 (12%) had high pretest probability, 101 (32%) moderate, and 184 (57%) low. CT scans were interpreted as positive for PE in 57 patients (17.8%). Regardless of the pretest probability of PE, 96.5% of patients with a positive CTPA were treated with anticoagulants. Even under an optimistic assumption of CTPA test characteristics, as many as 25.4% of these patients may have been treated unnecessarily as a result of a false-positive diagnosis. Most of these patients had a low pretest probability of PE. Failure to utilize Bayesian reasoning when interpreting CTPA may lead to false-positive diagnoses of pulmonary embolism in a substantial proportion of patients.

Bias due to False-Positive Diagnoses in an Automated Health Insurance Claims Database

Automated database studies have become a cornerstone of drug safety assessment. To assess the reliability of automated data, we compared the hospitalisation and mortality rates among three similar studies of automated healthcare databases in North America. Similar protocols were used to identify patients diagnosed with chronic obstructive pulmonary disease (COPD) who were treated with inhaled bronchodilators or inhaled corticosteroids in the Saskatchewan Health Database (SHD), the Kaiser Permanente Medical Care Program (KPMCP) of Northern California, and a proprietary automated insurance claims database available from i3 (formerly Ingenix). Automated data were used to compute incidence rates of total hospitalisation, cardiovascular (CV) hospitalisation and hospitalisation due to several specific types of CV outcomes. Record linkage with registries of vital statistics was used to identify deaths, obtain death certificates, and compute rates of total mortality, CV mortality and deaths due to certain CV outcomes. We compared rates in the i3 population with rates in the other two populations using age-adjusted rate ratio estimates and 95% CIs. The i3 cohort had approximately one-half the rates of total mortality, CV mortality and total hospitalisations, but twice the rate of CV hospitalisations, compared with each of the other two database cohorts. The unexpectedly higher rates of CV hospitalisations in the i3 population are inconsistent with its lower CV mortality, total mortality and total hospitalisation rates. This discrepancy is not readily explained by a higher prevalence of CV disease or procedures, random variation or confounding. Instead, high CV hospitalisation rates in the i3 population are consistent with a high rate of false-positive diagnoses recorded on insurance billing claims. These results underscore the importance of ensuring valid endpoints in automated claims databases.

Comparing the Diagnostic Accuracy of Six Potential Screening Instruments for Bipolar Disorder in Youths Aged 5 to 17 Years

To compare the diagnostic efficiency of six index tests as predictors of juvenile bipolar disorder in two large outpatient samples, aged 5 to 10 and 11 to 17 years, gathered from 1997 to 2002. DSM-IV diagnosis was based on a semistructured diagnostic interview (Schedule for Affective Disorders and Schizophrenia for School-Age Children) with the parent and youth sequentially, blind to scores on the index tests. Participants were 318 youths aged 5 to 10 (50% with bipolar diagnoses) and 324 youths aged 11 to 17 (41% with bipolar diagnoses). Areas under the curve (AUCs) from receiver operating characteristic analyses and multilevel likelihood ratios quantified test performance. Parent report (AUCs from 0.78 to 0.84 in both age groups) outperformed teacher (AUCs 0.57 in the younger sample and 0.70 in the older sample) or adolescent measures (AUCs 0.67 [General Behavior Inventory] and 0.71 [Youth Self-Report]) at identifying bipolar disorders. Combining tests did not produce clinically meaningful classification improvement. Parent report was more useful than teacher report or adolescent self-report on the index tests studied. Results generally replicated across both age groups. Parent report on these instruments could facilitate differential diagnosis of bipolar disorder in youths aged 5 to 17 years, especially by decreasing the rate of false-positive diagnoses.

Outcome of fetuses with clubfeet diagnosed by prenatal sonography.

To determine the outcome of fetuses with clubfoot diagnosed by prenatal sonography. We identified all fetuses scanned at our institution from May 1989 to May 2002 in whom clubfoot was suspected or diagnosed on prenatal sonography. From maternal and neonatal medical records, we collected the following information when available: unilateral or bilateral clubfoot, gestational age at diagnosis, other sonographic findings, and pregnancy outcome, including pathologic reports and neonatal findings at birth. One hundred twenty-one fetuses had prenatal sonographic suspicion or diagnosis of clubfoot. Twenty-two had no follow-up information, and 12 fetuses were terminated with fetal parts that could not be evaluated at pathologic examination, leaving 87 study cases. Outcome information was from neonatal records in 51 and from pathologic reports in 36. The gestational age at diagnosis ranged from 12.3 to 39.2 weeks, with a mean of 22.2 weeks. Forty-two (48%) had unilateral clubfoot, and 45 (52%) had bilateral clubfoot on sonography. The false-positive rate was significantly higher with unilateral clubfoot than bilateral clubfoot (12 [29%] of 42 versus 3 [7%] of 45; P < .05). Other anomalies were more common with bilateral clubfoot than with unilateral clubfoot (34 [76%] of 45 versus 23 [55%] of 42; P < .05), the most common being other musculoskeletal anomalies, neural tube defects, and cardiovascular anomalies. Of fetuses with information about chromosomes, the rates of aneuploidy were similar for unilateral and bilateral clubfoot (5 [28%] of 18 versus 10 [32%] of 31; P > .05). Fetuses with an antenatal sonographic diagnosis of clubfoot often have other anomalies, aneuploidy, or both. The false-positive rate for diagnosis of clubfoot is higher for unilateral clubfoot than bilateral clubfoot. The rate of associated anomalies is higher with bilateral clubfoot than unilateral clubfoot.

The rate of false-positive results with EUS-guided fine-needle aspiration

Background: The aims of this study were to determine the rate of false-positive diagnosis with EUS-guided fine-needle aspiration and to identify factors contributing to this type of error. Methods: The records of 577 patients undergoing EUS-guided fine-needle aspiration were reviewed and a subset of 188 patients with malignant cytology who underwent surgery was identified. Operative histopathology was compared with EUS-guided fine-needle aspiration cytopathology and false-positive cases were identified. An experienced cytopathologist, who was not involved with the original interpretation of the specimens, reviewed these cases to identify any factor(s) contributing to the errors. Results: Three cases of false-positive diagnosis were identified (1.6%; 95% CI [0.3%, 4.6%]). By aspiration site, the false-positive rates were as follows: pancreas 2/39 (5.1%), 95% CI [0.6%, 17.3%]; lymph nodes 1/136 (0.7%), 95% CI [0.02%, 4.0%]; and other sites 0/13, 95% CI [0.0%, 24.7%]. In both instances of a false-positive diagnosis for a pancreatic aspiration cytologic specimen, interpretative errors were identified. The false-positive interpretation of cytologic material aspirated from a lymph node occurred in a patient without any evidence for malignancy at surgery. In 111 patients with confirmed esophageal, gastric, or rectal malignancy undergoing EUS-guided fine-needle aspiration of nonperitumoral lymph nodes, there was no false-positive diagnosis, suggesting that specimen contamination by luminal tumor is rare. Conclusion: The overall rate of false-positive diagnosis for EUS-guided fine-needle aspiration is similar to that reported for other modalities. Most false-positive diagnoses are caused by interpretation errors. (Gastrointest Endosc 2002;56:868-72.)

The rate of false-positive results with EUS-guided fine-needle aspiration.

The aims of this study were to determine the rate of false-positive diagnosis with EUS-guided fine-needle aspiration and to identify factors contributing to this type of error. The records of 577 patients undergoing EUS-guided fine-needle aspiration were reviewed and a subset of 188 patients with malignant cytology who underwent surgery was identified. Operative histopathology was compared with EUS-guided fine-needle aspiration cytopathology and false-positive cases were identified. An experienced cytopathologist, who was not involved with the original interpretation of the specimens, reviewed these cases to identify any factor(s) contributing to the errors. Three cases of false-positive diagnosis were identified (1.6%; 95% CI [0.3%, 4.6%]). By aspiration site, the false-positive rates were as follows: pancreas 2/39 (5.1%), 95% CI [0.6%, 17.3%]; lymph nodes 1/136 (0.7%), 95% CI [0.02%, 4.0%]; and other sites 0/13, 95% CI [0.0%, 24.7%]. In both instances of a false-positive diagnosis for a pancreatic aspiration cytologic specimen, interpretative errors were identified. The false-positive interpretation of cytologic material aspirated from a lymph node occurred in a patient without any evidence for malignancy at surgery. In 111 patients with confirmed esophageal, gastric, or rectal malignancy undergoing EUS-guided fine-needle aspiration of nonperitumoral lymph nodes, there was no false-positive diagnosis, suggesting that specimen contamination by luminal tumor is rare. The overall rate of false-positive diagnosis for EUS-guided fine-needle aspiration is similar to that reported for other modalities. Most false-positive diagnoses are caused by interpretation errors.

Liver Lesions: Manganese-enhanced MR and Dual-Phase Helical CT for Preoperative Detection and Characterization—Comparison with Receiver Operating Characteristic Analysis

The purpose of this study was to compare, by means of receiver operating characteristic (ROC) analysis, dual-phase helical computed tomography (CT) and manganese-enhanced magnetic resonance (MR) imaging in the detection and characterization of hepatic lesions in patients prior to surgery. Twenty-five patients known to have or suspected of having hepatic lesions who were eligible for surgery underwent dual-phase (ie, arterial and portal phase) helical CT and phased-array MR imaging (ie, unenhanced fast spin-echo T2-weighted imaging and gradient-echo T1-weighted imaging performed before and after administration of mangafodipir trisodium). All images were reviewed independently by three off-site blinded reviewers who separately reviewed the CT scans and MR images. The standard of reference was findings at surgery, intraoperative ultrasonography (US), and histopathologic examination. ROC curves were established to analyze the results for each reader and modality. Ninety-four lesions (77 malignant and 17 benign) were revealed at surgery, intraoperative US, and/or histopathologic examination. The overall rate of lesion detection for the three readers at CT was 81.9% +/- 7.8, 90.4% +/- 5.9, and 76.6% +/- 8.6. At MR imaging, the detection rates were 72.3% +/- 9.0, 71.3% +/- 9.1, and 69.1% +/- 9.3 (P =.001 for the difference between MR and CT). The average rate of false-positive diagnoses in patients was 14.1% at CT and 6.4% at MR imaging (P =.06 for the difference between MR and CT). The mean areas under the alternative-free-response ROC curves were 0.74 for MR and 0.72 for CT (P =.751, not significant). In detection and characterization of liver lesions, manganese-enhanced MR imaging and dual-phase helical CT were not statistically different.

Why do primary care doctors diagnose depression when diagnostic criteria are not met?

This study examines predictors of false positive depression diagnoses by primary care doctors in a sample of primary care attendees, taking the patients' diagnostic status from a self-report measure (Depression Screening Questionnaire, DSQ) as a yardstick against which to measure doctors' correct and false positive recognition rates. In a nationwide study, primary care patients aged 15–99 in 633 doctors' offices completed a self-report packet that included the DSQ, a questionnaire that assesses depression symptoms on a three-point scale to provide diagnoses of depression according to the criteria of DSM-IV and ICD-10. Doctors completed an evaluation form for each patient seen, reporting the patient's depression status, clinical severity, and treatment choices. Predictor analyses are based on 16,909 patient-doctor records. Covariates examined included depression symptoms, the total DSQ score, number and persistence of depression items endorsed, patient's prior treatment, history of depression, age and gender. According to the DSQ, 11.3% of patients received a diagnosis of ICD-10 depression, 58.9% of which were correctly identified by the doctor as definite threshold, and 26.2% as definite subthreshold cases. However, an additional 11.7% of patients not meeting the minimum DSQ threshold were rated by their doctors as definitely having depression (the false positive rate). Specific DSQ depression items endorsed, a higher DSQ total score, more two-week depression symptoms endorsed, female gender, higher age, and patient's prior treatment were all associated with an elevated rate of false positive diagnoses. The probability of false positive diagnoses was shown to be affected more by doctors ignoring the ‘duration of symptoms’ criterion than by doctors not following the ‘number of symptoms’ criterion for an ICD or DSM diagnosis of depression. A model selection procedure revealed that it is sufficient to regress the ‘false positive diagnoses’ on the DSQ-total score, symptoms of depressed mood, loss of interest, and suicidal ideation; higher age; and patient's prior treatment. Further, the total DSQ score was less important in prediction if there was a prior treatment. The predictive value of this model was quite good, with area under the ROC-curve = 0.86. When primary care doctors use depression screening instruments they are oversensitive to the diagnosis of depression. This is due to not strictly obeying the two weeks duration required by the diagnostic criteria of ICD-10 and DSM-IV. False positive rates are further increased in particular by the doctor's knowledge of a patient's prior treatment history as well as the presence of a few specific depression symptoms. Copyright © 2000 Whurr Publishers Ltd.

Telomerase activity in pure pancreatic juice for the diagnosis of pancreatic cancer may be complementary to K-ras mutation

Background: The usefulness of K- ras mutation in pancreatic juice for the diagnosis of pancreatic cancer is questionable. Telomerase is positive in pancreatic cancer but rarely in benign pancreatic diseases. We conducted this study to determine the usefulness of K- ras mutation and telomerase activity in pancreatic juice for the diagnosis of pancreatic cancer. Methods: Pancreatic juice collected during endoscopic retrograde cholangiopancreatography was examined in 31 patients: 12 with pancreatic cancer, 11 with chronic pancreatitis, and 8 control patients. The K- ras gene was detected by using the restriction fragment length polymorphism method. Telomerase activity was detected by using the telomeric repeat amplification protocol. Results: K- ras mutation was positive in 75% (9 of 12) of pancreatic cancers and in 27% (3 of 11) of cases of chronic pancreatitis but in none of the control patients. Telomerase activity was detected in 92% (11 of 12) of pancreatic cancers and in 18% (2 of 11) of cases of chronic pancreatitis. The diagnostic value in pancreatic cancer was comparable between K- ras mutation and telomerase when evaluated separately. However, by combining these 2 methods, the specificity rose to 100%. Conclusions: For the diagnosis of pancreatic cancer, telomerase activity in pancreatic juice may possibly be complementary to K- ras mutation because it may decrease the rate of false-positive diagnosis. (Gastrointest Endosc 2000;51:708-13.)