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Results for “Sensitivity and Specificity”

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PubMed1978

Diagnosis of ventricular septal defect by pulsed Doppler echocardiography. Sensitivity, specificity and limitations.

The M-mode echocardiographic findings of ventricular septal defect (VSD) are nonspecific. A specific pulsed Doppler echocardiographic (PDE) diagnosis of VSD can be made by following the turbulent VSD jet through the septum. To assess the sensitivity, specificity and limitations of PDE diagnosis of VSD, 105 children undergoing cardiac catheterization were examined by PDE. These children had a variety of cardiac defects, and a PDE diagnosis of VSD was made in 46/51 (90%) who had VSD proven at catheterization. There was one false positive PDE diagnosis of VSD, for a specificity of 98%. Factors influencing the ability to diagnose VSD by PDE include the location of the defect, level of pulmonary vascular resistance and direction of blood flow through the VSD. The presence of additional defects did not interfere with PDE diagnosis of VSD. The PDE detection of additional defects may identify situations where M-mode echocardiographic estimation of dimensions may not be indicative of the size of VSD shunt.

Adolescent↗

PubMed1993

Sensitivity, specificity and predictive value of physical examination, culture and other laboratory studies in the diagnosis during early infancy of vertically acquired human immunodeficiency virus infection.

The medical records of 142 infants referred for evaluation solely because they were born to human immunodeficiency virus (HIV)-infected mothers (i.e. not because of signs or symptoms suggesting HIV infection), were reviewed. The infection status of 85 of these infants has been determined; 17 (20%) have confirmed HIV infection and 68 have seroreverted to HIV and lack evidence of infection. During the first 6 months of life HIV culture had better sensitivity, specificity, positive predictive value and negative predictive value for diagnosis of HIV infection than did physical examination, serum immunoglobulin determination or HIV p24 antigen determination. Of the 16 HIV-infected infants who were available for evaluation during the first 6 months of life, all had at least one culture from blood positive for HIV. Two of 4 and 10 of 11 infants were culture-positive at birth and during the first 3 months of life, respectively. A positive HIV culture results was the earliest finding of infection in 15 infants; 10 of these infants concomitantly were found to have hyperimmunoglobulinemia (8 cases) and/or an abnormal physical examination (4 cases). One HIV-infected infant developed hyperimmunoglobulinemia G and A at age 3 months without other evidence of HIV infection until age 5 months when a positive HIV culture was noted. All HIV-infected infants had abnormal findings by physical examination, a positive HIV culture, and/or hyperimmunoglobulinemia by 3 months of age. Infants with normal physical examination and laboratory test results at 3 and/or 6 months of age invariably were HIV-uninfected.

Female↗

PubMed2003

[All that neurologist would like to know about sensitivity, specificity and predictive values].

The aim of the diagnostic process is to establish the prevalence or probability of a disease given a clinical picture. A diagnostic test could be considered as every piece of information obtained from a patient. Diagnostic test can be done throughout technical devices, medical examinations or questionnaire. The diagnostic test offers information that allows us to classify patients according a different probability to be sick. The operative validity of a test can be done in terms of diagnostic accuracy. It means the ability to truly classify a patient in the right clinical situation. Diagnostic accuracy is the quality of the information provided by a test (sensitivity, specificity). Diagnostic usefulness is the practical value of the provided information. The predictive value of a diagnostic test depends on its accuracy and the prevalence of the disease in the setting where the diagnostic process is to be made. Decision making with the information provided by the test implies to consider the consequences of the false result.

Area Under Curve↗

PubMed1997

Sensitivity, specificity and predictive values of breast imaging in the detection of cancer.

In an observational follow-up study we determined whether the combined use of mammography and breast ultrasonography is an appropriate diagnostic tool to select patients with symptomatic breast disease who need additional pathological evaluation. Mammography and ultrasound were used as complementary diagnostic modalities in 3014 consecutively referred and mainly symptomatic patients. Sensitivity, specificity, predictive values and likelihood ratios were calculated according to standard procedures. Virtually complete follow-up was obtained by correlating the radiological diagnosis with clinical records, final pathological findings, records from the Cancer Register and data from questionnaires sent to the general practitioners of all the referred patients. After an average follow-up period of 30 months, the sensitivity for breast cancer detection was 92.0% and the specificity 97.7%. A positive predictive value of 68.0%, a negative predictive value of 99.6%, a positive likelihood ratio of 40 and a negative likelihood ratio of 0.08 were found. The mean diagnostic delay as a result of false negative examinations was 9 months (range 0-20 months). We conclude that breast imaging in routine daily practice, consisting of the integral use of mammography and ultrasonography, is an appropriate tool in the detection of cancer and should be included in the work-up of symptomatic breast disease.

Adult↗

PubMed1981

Assessment of the sensitivity, specificity, and reproducibility of the indirect immunofluorescent technique for the diagnosis of amebiasis.

The indirect immunofluorescence (IIF) test was used to study antibody titers to Entamoeba histolytica in various manifestations of clinical amebiasis by comparing the results with parasitological and clinical data from confirmed cases. The sensitivity, specificity, and reproducibility of this test for diagnosis were also studied. A high degree of correlation was found between reactivity in the IIF test and confirmed cases of amebic liver abscess. A positivity rate of 96% in sera of confirmed cases of amebic liver abscess in the present study compares favorably with the results of other workers. The IIF test is very useful in the diagnosis of hepatic amebiasis but is less sensitive for amebic dysentery. The test could not be used to differentiate between hepatic amebiasis and amebic dysentery. The IIF test was insensitive for amebic colitis and of no diagnostic value. Specificity and reproducibility of the test were good, as shown by results obtained with sera from patients with parasitic infections other than amebiasis.

Amebiasis↗

PubMed1973

Inhibition by oxisuran of cell-mediated hypersensitivity by decrease in numbers of specifically sensitized cells.

Oxisuran, 2-([methylsulfinyl]acetyl)pyridine, has previously been shown to selectively suppress cell-mediated immunity, as measured by prolongation of allograft survival, without inhibition of humoral immunity. In the present investigation, the influence of this compound on lymphoid cell transfer of delayed hypersensitivity was studied. In actively sensitized animals, including endotoxin-sensitized mice and rabbits, ovalbumin-, dinitrochlorobenzene-, and dinitrofluorobenzene-sensitive guinea pigs, or tuberculin-sensitive rats, daily treatment during the interval just preceding the elicitation and expression of the hypersensitivity was most inhibitory. In both endotoxin-sensitive mice and ovalbumin-sensitive guinea pigs, treatment of the sensitized cell donor just prior to lymphoid cell harvest and transfer resulted in inhibition of the expression of the hypersensitivity in untreated recipients. Approximately 10(4) fewer specifically sensitized lymphoid cells, but not fewer viable cells, were present in passively transferred cell preparations. In contrast, treatment of the lymphoid cell recipient in the same experimental model did not influence the expression of the transferred hypersensitivity. The results suggest that oxisuran may influence an as yet undefined event prior to the expression of a cell-mediated hypersensitivity response in sensitized animals.

Animals↗

PubMed2004

Species-specific sensitivity of aquatic macrophytes towards two herbicides.

The s-triazine herbicide terbutylazine, an inhibitor of photosystem II, is often found in surface waters in concentrations < 1 microg L(-1), but concentrations up to 13 microg L(-1) have been measured. To study the effect on the aquatic flora, we tested the sensitivity of 10 aquatic macrophyte species and a natural epiphyte community in a 2-week laboratory multispecies test at constant terbutylazine concentrations and two irradiance regimes. The data were described by a log-logistic concentration-response model and species sensitivity distributions (SSDs) were created from the EC50 and EC10 values. The 5% hazard concentration (HC5) of the EC10-based SSD for terbutylazine was 1 and 3 microg L(-1); hence the low chronic terbutylazine concentrations measured in the environment are not likely to affect the macrophyte community. To compare the species sensitivity between different groups of herbicides, SSDs were constructed from a published study on the sulfonylurea metsulfuron-methyl, an inhibitor of acetolactate synthase. There was no correlation between species-specific sensitivity to the two herbicides; hence, the combined exposure of different herbicides might affect the macrophyte community more broadly rather than seriously affecting a few susceptible species. Evaluating the standard procedure of leaving at least a factor of 100 between the EC50 of standard tests on Lemna sp. and the predicted environmental concentration seems to be protective for at least 95% of the macrophyte species for both terbutylazine and metsulfuron-methyl.

Arylsulfonates↗

PubMed1990

WEHI 164 subclone 13 assay for TNF: sensitivity, specificity, and reliability.

Tumor necrosis factor alpha (TNF) is a peptide monokine involved in a number of immune reactions. To further understand the role of TNF in disease states it is critical to have an inexpensive, yet sensitive and specific assay. Additionally, the effects of prostaglandin E2 (PGE2), dexamethasone (dex), and cyclosporine A (CsA) on TNF gene expression have been studied, although little is known of the effects these compounds have on TNF containing samples. The aim of this study is to determine the sensitivity and specificity of a highly sensitive cell line to the actions of TNF, and to elucidate parameters which affect the stability of TNF in biological fluids. Dex and PGE2 at concentrations of 10(-5), 10(-7), and 10(-9) M, were shown not to effect the WEHI assay, and neither did CsA (10 ng/ml-1 ug/ml). The cells were not lysed by recombinant murine IL-1 alpha or beta, human recombinant IL-1 alpha or beta, human recombinant IL-2 or human recombinant IL-6 at concentrations ranging from 0.02 pg/ml to 1.0 ug/ml, or murine gamma-IFN from 100 pg/ml to 10 ng/ml. TNF containing samples with 1%-10% fetal calf serum maintained their cytolytic activity even after three freeze-thaw cycles. Serum samples did not lose any cytolytic activity with up to 11 cycles of freezing and thawing whereas, tissue culture media, containing TNF, lost significant activity with freeze-thawing. The WEHI assay has successfully detected cytolytic activity from lipopolysaccharide stimulated specimens from a number of different species. These data show the utility of this highly sensitive and specific assay. Furthermore, the WEHI assay showed a high degree of reproducibility in repeated assays.

Animals↗

PubMed1984

Interpretation of laboratory tests using a programmable hand-held calculator: calculation of posterior probability and relative risk on the basis of prior probability and sensitivity, specificity and result of the test.

A program is presented for the Hewlett-Packard HP- 41C programmable hand-held calculator that calculates the posterior probability and relative risk of an event (e.g. a disease) on the basis of prior probability (prevalence) and sensitivity, specificity and result of the test.

Bayes Theorem↗

PubMed1991

Demonstration of specifically sensitized lymphocytes in patients treated with an aqueous mistletoe extract (Viscum album L.).

Lymphocytes of 25 patients treated with an aqueous mistletoe extract (Viscum album L.) for up to 6 months (group 1), up to 2 years (group 2), and more than 2 years (group 3) were examined in 3- and 7-day cultures for specifically sensitized lymphocytes. The whole extract (HM), the lectin-polysaccharide fraction (HM-LP), and the 'viscotoxin' fraction (HM-V) were added at concentrations ranging from 0.5 micrograms to 12.5 mg extract/ml. Lymphocytes from four of the nine group 2 patients and five of the ten group 3 patients reacted specifically with HM and HM-LP at an optimal dose of 5.0 mg/ml, but did not react with HM-V. Stimulation indices varied between 1.6 and 16. In the patients of group 3 this effect was observed only when their lymphocytes were co-stimulated in the 3-day cultures with phytohemagglutinin (PHA), in contrast to the four patients of group 2 who reacted only in the 7-day cultures with HM-LP without PHA co-stimulation. Patients' lymphocytes had to be protected from mistletoe lectin-induced cytotoxicity by the addition of their own sera containing anti-mistletoe lectin antibodies. Lymphocytes from tumor patients (n = 18) never treated with mistletoe extracts and healthy individuals (n = 18) showed no specific proliferative response when tested in 3- and 7-day cultures.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibody Formation↗

PubMed1994

Highly sensitive, specific, and stable new fluorescent DNA stains for confocal laser microscopy and image processing of normal paraffin sections.

The area, volume, shape, DNA content, and chromatin pattern of nuclei can be important for the diagnosis and prognosis of cancers. Confocal laser scan microscopy can be useful to obtain such information by optical slicing and three-dimensional (3-D) reconstruction of nuclei in thick paraffin sections. To retrieve individual quantitative features from the section, highly sensitive, specific, and stable fluorescent stains are required. Two new nuclei acids stains (TOTO-1 iodide and YOYO-1 iodide) can detect picogram amounts of nucleic acids in gels. Despite their high sensitivity to detect DNA, they have not been used to stain nuclei in paraffin embedded tissue sections (as routinely applied in surgical cancer pathology). We have developed a technique to stain nuclei in 4% buffered formaldehyde fixed paraffin tissue sections using TOTO-1 iodide and YOYO-1 iodide. The technique developed gives bright specific staining of the nuclei (with nearly zero background intensity, much less than with acriflavine). Moreover, TOTO-1 iodide and YOYO-1 iodide stains both give fluorescent signals only when they interact with DNA. Thus washing off the excess stain left on the stained specimen is not necessary (washing of excessive stain is necessary with acriflavine). Care has to be taken that the deparaffinizing liquids (xylol etc.) are not polluted with eosin (a frequently used counterstain in surgical pathology specimens), as this gives undesired fluorescence of cytoplasm and connective tissue at the same wavelength as TOTO-1 iodide and YOYO-1 iodide. Contrary to acriflavine, bleaching of TOTO-1 iodide and YOYO-1 iodide fluorescence is minimal, even after 30 min continuous laser light excitation.(ABSTRACT TRUNCATED AT 250 WORDS)

Acriflavine↗

PubMed1982

Thallium-201 myocardial scintigraphy: improved sensitivity, specificity and predictive accuracy by application of a statistical image analysis algorithm.

Exercise and 3 hour delayed redistribution thallium-201 myocardial perfusion imaging was performed in 107 patients including 87 patients with documented coronary artery disease and 20 patients with normal coronary arteriograms. A computer algorithm for statistical analysis and redisplay of the analog scintillation data was developed to augment the visual analysis of the standard analog image. The basic algorithm identified the myocardial area (pixel) with the most absolute counts and developed an appropriate standard deviation range from a table. All pixels in the area of the myocardium containing absolute counts below three standard deviation ranges (or approximately 6 standard deviations) were deleted from the final image. The remaining pixels were redisplayed in a digitized bimodal format and the image photographed. Two experienced observers compared visual analysis of the analog image alone and the analog image in conjunction with the computer-analyzed image for sensitivity, specificity and predictive accuracy in the detection of perfusion defects in patients with coronary artery disease and in normal subjects. Sensitivity in patients with coronary artery disease and in normal subjects. Sensitivity in patients with coronary artery disease for the analog scintillation image alone was 79 percent (69 of 87) and with computer analysis 95 percent (83 of 87). Specificity in the patients with no coronary disease was 100 percent (20 of 20) for both techniques. The predictive accuracy of the test was 83 percent (89 of 107) for the analog image alone and 96 percent (103 of 107) for the two images combined. It is concluded that use of a computer statistical analysis algorithm of thallium-201 analog myocardial perfusion images improves the accuracy of detection of perfusion defects in patients with coronary artery disease.

Computers↗

PubMedDate not supplied

Abrogation of G2 checkpoint specifically sensitize p53 defective cells to cancer chemotherapeutic agents.

BACKGROUND: Chkl is a checkpoint gene that is activated after DNA damage. It phosphorylates and inactivates Cdc25C at the late G2 phase. The inactivation of Cdc25C and consequently, the inactivation of Cdc2, are required for the G2 arrest induced by DNA damage. METHODS: We treated 184B5 cell line and its E6 transformed cell lines with adriamycin in the presence of staurosporine or UCNO1 and examined G2 arrest and cell death. RESULTS: We found that adriamycin induced a p53 and p21 response as well as a G1 arrest in 184B5 cells, but not in its E6 transformed cells. Staurosporine or UCNO1 abrogated the G2 arrest induced by adriamycin in both cell lines. In addition, staurosporine or UCNO1 specifically sensitized p53 incompetent cells to adriamycin. CONCLUSION: G2/M checkpoint abrogators can potentially enhance the cytotoxic effect of conventional chemotherapeutic reagents specifically to tumor cells.

Alkaloids↗

PubMed1994

Sensitivity, specificity, and predictive values of reagent test strip estimations of blood urea nitrogen.

Azostix-reagent-tests(R) strips (Ames, Miles, Inc., Diagnostic Division, Elkhart, IN) were used to measure blood urea nitrogen values in blood samples from 125 dogs and cats at the North Carolina State University, College of Veterinary Medicine. Results of the tests were compared with standard serum urea nitrogen results. Sensitivity, specificity, and negative predictive values were high (86.4, 90.3, and 96.5%, respectively). Positive predictive value was low, 65.5% of the dogs and cats with elevated blood urea nitrogen values were correctly classified as abnormal The test performs well when the prevalence of abnormal values is near 50%.

Journal Article↗

PubMed2004

Sensitivity, specificity and predictive value of the echocardiography and troponin-T test combination in patients with non-ST elevation acute coronary syndromes.

INTRODUCTION: Patients with a negative troponin (TnT) result showed 1.4% mortality during a mean follow-up of 9-10 weeks. Mortality was greater in patients with an evidence of ischemic ECG changes and a negative TnT test (1.6-4.4%). Few studies have examined the efficacy of echocardiography (2DE) in patients with chest pain. The purpose of the present study was to determine the clinical utility, sensitivity and specificity of the combination of TnT levels and 2DE in patients presenting with chest pain, ST-depression, T-wave negative and no diagnostic ECG. METHODS: 280 consecutive patients with chest pain and presence of ST depression, T-wave inversion, and non-diagnostic ECG, acceptable 2DE window, evidence or no evidence of alterations of the segmentary motion, and evidence and no evidence of injury, as assessed by TnT and normal value of CK-CK MB, were enrolled. 2DE, blood CK, and TnT levels were controlled at entry and subsequent samples were obtained every 4 h for the first 12 h and then every 12 h. All patients performed angiography within 12-72 from admission. PTCA or CABG were performed according to angiographic findings and left ventricular function. RESULTS: The 280 patients (98 F/M 182), mean age 59.7+/-11.9 years, who met the entry criteria, were divided as follows: group 1: ST-segment depression (192 patients); group 2: T-wave inversion (36 patients); and group 3: non-diagnostic ECG (52 patients). The combination of positive TnT and wall motion alterations showed a higher sensitivity, specificity and predictive values in comparison with alone TnT or 2DE. Patients, with the concordance between TnT and 2DE, were at higher risk. Patients with negative combination in all groups (94), showed a low incidence of coronary stenosis (10.6%), as well as negative 2DE alone (102 patients) (12.7%), while patients with negative TnT (128) showed higher incidence of coronary stenosis (39%), p < 0.0001. CONCLUSION: Our results suggest that the combination of negative TnT test and negative 2DE in patients presenting to EDs with chest pain either with ECG changes or without ECG changes is a useful tool to identify those who can be discharged safely. We think that our data are important because by the combination we can identify the high risk (when positive) patients, reduce incidence of the false negative, but mostly it allows us to identify true negative patients to discharge safely.

Acute Disease↗

PubMed1988

Understanding the accuracy of tests with cutting scores: the sensitivity, specificity, and predictive value model.

While researchers usually are concerned about psychometric properties of psychological tests estimated using large samples, most clinical decision-makers must evaluate the accuracy of test results for individuals. This is particularly true as regards tests that have cutting scores to determine, for example, whether to assign a particular diagnosis or accept an applicant into a training program. This paper reviews a conceptual model that may foster improved understanding of test outcomes for individuals. The terms "sensitivity," "specificity," and "predictive value" are defined, and the relations of positive and negative predictive values to population base rates are emphasized. Examples from the psychological literature are presented to illustrate the utility of these concepts in clinical decision-making with psychological tests. Implications for test users, test developers, and instructors are discussed.

Depressive Disorder↗

PubMed2004

A single amino acid determinant governs the species-specific sensitivity of APOBEC3G to Vif action.

APOBEC3G (also known as CEM15) is an innate intracellular antiretroviral factor that is counteracted by the Vif protein of lentiviruses. While APOBEC3G orthologues from several species are active against a broad range of retroviruses, given Vif proteins have a narrow spectrum of activity. For instance, HIV-1 Vif efficiently blocks APOBEC3G from human but not African green monkey (AGM), whereas the reverse is observed with SIV(AGM) Vif. Here, we demonstrate that a single amino acid at position 128 of human and AGM APOBEC3G governs the virus-specific sensitivity of these proteins to Vif-mediated inhibition. Furthermore, we show that this phenotype correlates with the ability of Vif to bind APOBEC3G and interfere with its incorporation into virions. These results shed light on an important determinant of the tropism of primate lentiviruses.

APOBEC-3G Deaminase↗

PubMed1988

Simian AIDS ELISA: sensitivity, specificity and predictive values based on a comparison with Western blot technique.

Simian Acquired Immunodeficiency Syndrome (SAIDS) is an important disease in captive primates in the United States associated with an unusually high mortality rate. Isolation of a type D retrovirus as the cause of SAIDS was rapidly followed by the development of an enzyme linked immunosorbent assay (ELISA) to determine the exposure of rhesus macaques (Macaca mulatta) to this virus. With increased use of the ELISA, a better understanding for interpretation of results was needed. One hundred thirty-one rhesus macaques were tested for the presence of antibody against SAIDS type D retrovirus (SRV) by both ELISA and Western blot techniques. Sensitivity, specificity and predictive values for the SAIDS ELISA were calculated for two populations based on a comparison with Western blot results. Sera was tested from two distinct populations, an endemic and a control population. Seventy-one macaques from a half-acre outdoor corral where SAIDS was first recognized made up the endemic population. Sixty rhesus macaques from both indoor and outdoor areas where the disease was not recognized made up the control population. This study has shown the ELISA to be a useful screening tool based on its high sensitivity for both endemic and control populations. This screening method provides a rapid and economical way to diagnose and manage SAIDS in captive non-human primate colonies.

Animals↗