Search results for "False Positive Reactions"
showing 10 items of 37 documents
False-positive LSD testing in urine samples from intensive care patients.
1998
Unexpected positive results for lysergic acid diethylamide (LSD) were found in urine samples from 12 patients in an intensive care unit in a routine screening using the CEDIA DAU assay. None of these test results could be confirmed by high-performance liquid chromatography analysis, but all samples contained the mucolytic drug ambroxol. Further studies demonstrated that ambroxol exhibits a significant cross-reactivity in the CEDIA DAU LSD assay. Therefore, positive LSD results obtained with the CEDIA DAU assay have to be critically evaluated, particularly during the cold season, when infections of the respiratory tract often result in more frequent use of mucolytic medications.
Ultrasonography and alpha-fetoprotein in diagnosis of hepatocellular carcinoma in cirrhosis
1988
The accuracy of ultrasound (US) and alpha-fetoprotein (AFP) in the diagnosis of hepatocellular carcinoma (HCC) in 363 patients with cirrhosis (C) and a clinical suspicion of HCC was assessed. The ultrasonographic patterns of HCC and their relationship with AFP values were analyzed. Echographic patterns were distributed as follows: 47 patients had sonodense lesions; 30 patients had hypoechoic lesions; 47 had mixed-pattern lesions, and in four patients focal dilated intrahepatic bile ducts were demonstrated. The sensitivity of US was 90%; specificity was 93.3%. Serum AFP level greater than or equal to 500 ng/ml (RIA) was the first clue to the diagnosis in 71 patients (48.6%); specificity was …
A smart and operator independent system to delineate tumours in Positron Emission Tomography scans
2018
Abstract Positron Emission Tomography (PET) imaging has an enormous potential to improve radiation therapy treatment planning offering complementary functional information with respect to other anatomical imaging approaches. The aim of this study is to develop an operator independent, reliable, and clinically feasible system for biological tumour volume delineation from PET images. Under this design hypothesis, we combine several known approaches in an original way to deploy a system with a high level of automation. The proposed system automatically identifies the optimal region of interest around the tumour and performs a slice-by-slice marching local active contour segmentation. It automa…
Disordered recognition memory: recollective confabulation.
2013
Recollective confabulation (RC) is encountered as a conviction that a present moment is a repetition of one experienced previously, combined with the retrieval of confabulated specifics to support that assertion. It is often described as persistent deja vu by family members and caregivers. On formal testing, patients with RC tend to produce a very high level of false positive errors. In this paper, a new case series of 11 people with dementia or mild cognitive impairment (MCI) and with deja vu-like experiences is presented. In two experiments the nature of the recognition memory deficit is explored. The results from these two experiments suggest - contrary to our hypothesis in earlier publi…
Patient Alert to detect ICD lead failure: efficacy, limitations, and implications for future algorithms.
2006
Aims An algorithm that alerts implantable cardioverter-defibrillator (ICD) patients, in case of abnormal lead impedance (Patient Alert™, Medtronic), may help to recognize lead dysfunction. We aimed to determine the utility of Patient Alert for ICD lead-failure detection in a prospective study. Methods and results Three hundred and sixty ICD patients were followed for 22±14 months. Patient Alert was active for pacing impedance 2000–3000 Ω, and high-voltage conductor impedance 200 Ω. Ten alert events and a total of 29 severe system complications occurred. Patient Alert detected three of 10 ICD lead failures, with a positive predictive value (PPV) of 77.8% for any severe system complication. R…
Age as a Confounding Factor for the Accurate Non-Invasive Diagnosis of Advanced NAFLD Fibrosis
2017
OBJECTIVES Non-invasive fibrosis scores are widely used to identify/exclude advanced fibrosis in patients with non-alcoholic fatty liver disease (NAFLD). However, these scores were principally developed and validated in patients aged between 35 and 65 years of age. The objective of this study was to assess the effect of age on the performance of non-invasive fibrosis tests in NAFLD. METHODS Patients were recruited from European specialist hepatology clinics. The cohort was divided into five age-based groups: ≤35 (n=74), 36-45 (n=96), 46-55 (n=197), 56-64 (n=191), and ≥65 years (n=76), and the performance of the aspartate aminotransferase (AST)/alanine transaminase (ALT) ratio, fibrosis 4 (F…
Diagnostic efficacy of the ELISA test for the detection of deamidated anti-gliadin peptide antibodies in the diagnosis and monitoring of celiac disea…
2009
Background and Aim: We evaluated the diagnostic performance of an ELISA test for anti-gliadin IgA and IgG antibodies, which uses synthetic deamidated gliadin peptides (anti-gliadin antibodies, AGAs) as coating; the results were compared with a test that uses extracted gliadin (AGAe). Methods: The study was conducted on the sera of 144 patients suffering from celiac disease (CD), including 20 patients with IgA deficiency and 9 who were following a gluten-free diet (GFD), and 129 controls. Results: In the 115 CD patients (without IgA deficiency), the sensitivity of AGAe IgA and IgG was 32.2 and 60.9%, whereas that of AGAs IgA and IgG was 59.1 and 72.2%. The specificity for AGAe IgA and IgG, a…
False-positive I-131 whole-body imaging after I-131 therapy for a follicular carcinoma.
1997
A 57-year-old man was treated with ablative radioiodine therapy for follicular thyroid carcinoma. The post-therapeutic whole body scans detected radionuclide accumulation in the area of the right occiput at the site of a cranial defect. The defect was caused by trauma in 1964. Bone scintigraphy did not show increased uptake in this area. Magnetic resonance imaging showed porencephaly, but it did not show a metasasis.
ENDOCRINE TUMOURS: Calcitonin in thyroid and extra-thyroid neuroendocrine neoplasms: the two-faced Janus.
2020
An increased calcitonin serum level is suggestive of a medullary thyroid cancer (MTC), but is not pathognomonic. The possibility of false positives or other calcitonin-secreting neuroendocrine neoplasms (NENs) should be considered. Serum calcitonin levels are generally assessed by immunoradiometric and chemiluminescent assays with high sensitivity and specificity; however, slightly moderately elevated levels could be attributable to various confounding factors. Calcitonin values >100 pg/mL are strongly suspicious of malignancy, whereas in patients with moderately elevated values (10–100 pg/mL) a stimulation test may be applied to improve diagnostic accuracy. Although the standard protoco…
Steatocrit test after a standard fatty meal: A new simple and sensitive test to detect malabsorption
1991
The steatocrit test, a simple semiquantitative method for determining fat content in stool, was performed after a standard fatty meal to detect malabsorption in patients with celiac disease. Thirty-seven children (mean age 2.6 +/- 2.1 years) with total atrophy of the intestinal villi and 79 controls (mean age 3.5 +/- 2.8 years) were studied. All subjects underwent a small-bowel biopsy, a D-xylose absorption test, a rapid triglyceride absorption test, and a steatocrit determination first on an uncontrolled diet and then again after a standard fatty meal. The steatocrit test after a fatty meal did not detect any false-positive or false-negative results, while the D-xylose test showed two fals…