Showing papers on "False positive paradox published in 1978"
TL;DR: In the authors' hands, CTT, CA, alkaline phosphatase, 75Se‐methionine and ultrasonography, in descending order, have given the highest percentage of correct diagnoses but false positive and false negative diagnoses prevented any single test from being conclusive.
Abstract: By contract with the National Cancer Institute, the accuracy of diagnostic techniques was assessed in 184 patients suspected of having pancreas cancer. Of 138 patients who were operated upon, 89 were found to have pancreas duct cancer, 30 had cancer of a different site of origin in the head of the pancreas region and in 19 there was no evidence of cancer at operation. All of the 46 patients who were not operated upon, 13 proven to have cancer and 33 patients discharged as free of cancer, were followed in our clinic. The majority of our patients presented with signs and symptoms of biliary obstruction. Computerized transaxial tomography (CTT) gave a "correct" diagnosis in 31 of 33 patients (94%) with proven cancer, there were 2 patients with a false negative report and a false positive diagnosis occurred in 8 of 20 patients (40%) without cancer. Celiac angiography (CA) gave a correct diagnosis in 78 of 94 patients (83%) with cancer, a false negative in 17%, and a false positive in 32%. 76Selenomethionine pancreas scan correctly diagnosed 27 of 36 patients (75%) with cancer, gave a false negative in 25% and a false positive in 31%. Ultrasonography gave a correct diagnosis in 18 of 27 patients with cancer (67%), a false negative in 33% and a false positive in 28%. Endoscopic retrograde cholangiopancreatography diagnosed correctly 8 of 11 cases (73%) of cancer, there were false negative diagnoses in 3 cases (27%) and false positives in 3 of 14 patients (21%). Duodenal aspiration techniques gave a very low percentage of correct diagnoses. Chronic pancreatitis most commonly gave rise to a false positive diagnosis. Serum alkaline phosphatase was elevated in 82% of patients, gave 18% false negatives and 33% false positives. Carcinoembryonic antigen (CEA) was elevated (greater than 2.5 ng/ml) in most of the pancreas cancer patients but also in patients with other cancers and with non-cancerous diseases. In our hands, CTT, CA, alkaline phosphatase, 75Se-methionine and ultrasonography, in descending order, have given the highest percentage of correct diagnoses but false positive and false negative diagnoses prevented any single test from being conclusive.
87 citations
TL;DR: The carcinogenicity and mutagenicity of 26 nitrosamines were compared to help validate the predictability of a short-term in vitro test.
Abstract: The carcinogenicity and mutagenicity of 26 nitrosamines were compared to help validate the predictability of a short-term in vitro test. 80% of the compounds showed agreement between the two characteristics, while 20% did not. Of the latter group, 8% were false positives and 12% were false negatives.
72 citations
01 Jan 1978
TL;DR: In this article, three serological tests for Brucellosis were compared with a serological classification of seradescribed asthe "probable infection status". Serashowing apparent false positive andapparent false negative reactions were identified, andweresubjected tosupplementary testing as appropriate.
Abstract: SUMMARY Results obtained from1887serausing three serological tests forbovine brucellosis werecompared witha serological classification ofseradescribed asthe 'probable infection status'. Serashowing apparent false positive andapparent false negative reactions wereidentified, andweresubjected tosupplementary testing asappropriate. Theserumagglutination test(SAT) gave35% apparent false negative reactions and5% apparent false positives. Thecomplement fixation test(CFT) gave12% apparent false negative reactions using warmfixation (CFTW)andatleast 5% usingcoldfixation (CFTC). Theroutine diagnostic systemusedinVictoria, in whichtheCFTWissupplemented bytheCFTCandtheSAT,gave9% apparent false negative reactions and2% apparent false positive reactions. Theradioimmunoasay gave1% or6% apparent false negative reactions, depending on theminimumdiagnostic value used. Atypical reactions intheCFTsometimes caused difficulties indiagnosis.
19 citations
TL;DR: Sera obtained from 1887 sera using three serological tests for bovine brucellosis were compared with a serological classification of sera described as the ‘probable infection status’.
Abstract: Results obtained from 1887 sera using three serological tests for bovine brucellosis were compared with a serological classification of sera described as the 'probable infection status'. Sera showing apparent false positive and apparent false negative reactions were identified, and were subjected to supplementary testing as appropriate. The serum agglutination test (SAT) gave 35% apparent false negative reactions and 5% apparent false positives. The complement fixation test (CFT) gave 12% apparent false negative reactions using warm fixation (CFTW) and at least 5% using cold fixation (CFTC). The routine diagnostic system used in Victoria, in which the CFTW is supplemented by the CFTC and the SAT, gave 9% apparent false negative reactions and 2% apparent false positive reactions. The radioimmunoassay gave 1% or 6% apparent false negative reactions, depending on the minimum diagnostic value used. Atypical reactions in the CFT sometimes caused difficulties in diagnosis.
16 citations
TL;DR: A search of the literature was conducted for the various substances reported to give a positive response to any of the above methods; all of those that were commercially available were tested with the modified Duquenois-Levine test and thin-layer chromatography (TLC) employed by this laboratory for marihuana identification as discussed by the authors.
Abstract: Many authors have reported using the Duquenois, Duquenois-Negm, Duquenois-Levine, or modified Duquenois-Levine color tests on various substances with varying results. Some authors [1] apparently consider any resultant color to be a positive response. Recently this diversity of testing methods has been used by defense lawyers in an attempt to confuse judges and juries. Therefore, a search of the literature was conducted for the various substances reported to give a positive response to any of the above methods; all of those that were commercially available were tested with the modified Duquenois-Levine test and thin-layer chromatography (TLC) employed by this laboratory for marihuana identification. In addition, other compounds of similar structures were selected and tested in like manner, as were minor components of Cannabis resin [2]. Another major objective was to determine if a mixture of materials that would lead to a false positive identification of marihuana could be made.
10 citations
01 Jan 1978
TL;DR: Effectiveness of mass-screening for cancer depends on five factors at least: incidence and history of the disease, diagnostic sensitivity, therapies resulting in high long-term survival rates, information and health education to motivate the largest possible number of people to participate, and costs as a result of the four factors.
Abstract: Effectiveness of mass-screening for cancer depends on five factors at least: (1) incidence and history of the disease, (2) diagnostic sensitivity to avoid a significant number of false negatives and false positives, (3) therapies resulting in high long-term survival rates, (4) information and health education to motivate the largest possible number of people to participate, and (5) costs as a result of the four factors mentioned above in terms of money spent per person, organization needed, manpower, etc.
10 citations
3 citations