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Results for “Sensitivity and Specificity”

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PubMed1988

Serological tests in leprosy. The sensitivity, specificity and predictive value of ELISA tests based on phenolic glycolipid antigens, and the implications for their use in epidemiological studies.

This paper examines the sensitivity and specificity of two ELISA assays for IgM antibodies to Mycobacterium leprae, one employing natural phenolic glycolipid and the other employing a synthetic disaccharide glycoconjugate as antigen. Estimates of sensitivity and specificity are derived, based on a panel of sera from leprosy cases in Malawi and various non-leprosy controls from the UK. Though both assays were able to identify a high proportion of multibacillary patients, neither was able to detect a high proportion of paucibacillary patients without considerable loss of specificity. The implications of the inverse relationship between sensitivity and specificity are discussed with reference to the predictive value of such tests in such areas as Malawi, where the large majority of cases are paucibacillary.

Enzyme-Linked Immunosorbent Assay↗

PubMed2006

Danish version of the Oswestry disability index for patients with low back pain. Part 2: Sensitivity, specificity and clinically significant improvement in two low back pain populations.

In studies evaluating the efficacy of clinical interventions, it is of paramount importance that the functional outcome measures are responsive to clinically relevant change. Knowledge thereof is in fact essential for the choice of instrument in clinical trials and for clinical decision-making. This article endeavours to investigate the sensitivity, specificity and clinically significant improvement (responsiveness) of the Danish version of the Oswestry disability index (ODI) in two back pain populations. Two hundred and thirty three patients with low back pain (LBP) and/or leg pain completed a questionnaire booklet at baseline and 8 weeks follow-up. Half of the patients were seen in the primary (PrS) and half in the secondary sectors (SeS) of the Danish Health Care System. The booklet contained the Danish version of the ODI, along with the Roland Morris Questionnaire, the LBP Rating Scale, the SF36 (physical function and bodily pain scales) and a global pain rating. At follow-up, a 7-point transition question (TQ) of patient perceived change and a numeric rating scale relating to the importance of the change were included. Responsiveness was operationalised using three strategies: change scores, standardised response means (SRM) and receiver operating characteristic (ROC) analyses. All methods revealed acceptable responsiveness of the ODI in the two patient populations which was comparable to the external instruments. SRM of the ODI change scores at 2 months follow-up was 1.0 for PrS patients and 0.3 for SeS (raw and percentage). A minimum clinically important change (MCID) from baseline score was established at 9 points (71%) for PrS patients and 8 points (27%) for SeS patients using ROC analyses. This was dependable on the baseline entry score with the MCID increasing with 5 points for every 10 points increase in the baseline score. We conclude that the Danish version of the ODI has comparable responsiveness to other commonly used functional status measures and is appropriate for use in low back pain patients receiving conservative care in both the primary and secondary sector.

Denmark↗

PubMed1993

Evaluation of sensitivity, specificity, and reproducibility of an optimized method for detecting clonal rearrangements of immunoglobulin and T-cell receptor genes in formalin-fixed, paraffin-embedded sections.

Following our recent reports of detecting clonal immunoglobulin and T-cell receptor gene rearrangements by the polymerase chain reaction, we have improved and simplified the technique for use in diagnostic histopathology laboratories and determined, on coded samples, the sensitivity, specificity, and reproducibility of the modified methodology in distinguishing malignant lymphoma from reactive lymphoid hyperplasia and nonlymphoid tumors. Using only three primer pairs for the immunoglobulin heavy chain and T-cell receptor beta and gamma chain genes on well-characterized lesions of widely varying morphology and immunophenotype, clonal rearrangements were detected in 65% of B-cell lymphomas, and 77-82% of T-cell tumors. Specificity and observer consistency ranged from 93-97%. The method requires very careful control, particularly to avoid misinterpretation of results because of contamination and nonspecific amplification, but in its present form is relatively simple and inexpensive, and gives results on single paraffin-embedded sections within 24 h.

Antibody Specificity↗

PubMedDate not supplied

Automated rescreening in cervical cytology. Mathematical models for evaluating overall process sensitivity, specificity and cost.

OBJECTIVE: To develop mathematical models to assist decision makers with the difficult task of evaluating the use of automated rescreening in the process of screening cervical smears. STUDY DESIGN: Using assumptions about incidence, per smear screening costs, and the sensitivity and specificity of cytotechnologists, pathologists and the rescreening device, basic probability models were developed to describe the overall sensitivity, specificity and cost of the screening process. RESULTS: The optimal screening policy is highly dependent on assumptions, and an automated system can significantly affect the overall system cost and accuracy. CONCLUSION: Mathematical planning models are valuable tools to assist decision makers in the design of a screening process for cervical smears.

Automation↗

PubMed1989

Parameters for evaluation of viability assays: accuracy, precision, specificity, sensitivity, and standardization.

The selection of appropriate viability assays is critical in evaluating the efficacy of any cryopreservation procedure. The appropriateness of a given assay depends on the specific tissue and the function which is being optimized. Although a broad range of "viability" assays have been used, these assays can be classified in seven principle groups: (i) Morphological procedures, including routine histology, surface antigen localization, and transmission electron or scanning microscopy; (ii) proliferation studies; (iii) metabolic assays; (iv) implantation; (v) mechanical assays; (vi) motility; and (vii) DNA or RNA synthetic assays. Regardless of the class of assay, each assay may be further characterized as qualitative, quantitative, or quantal and each type may vary in the degree of subjectivity. In selecting a specific viability assay, biological variability, assay bias, and the statistical probability of both Type I and Type II errors should be considered crucial. Here we discuss a number of critical factors involved in validating viability assays, including accuracy, precision, standardization, specificity, sensitivity, selection of statistical methodology, and range of the assay.

Animals↗

PubMed2006

[Sensitivity, specificity, predictive positive and negative value of the main clinical signs and symptoms of hydatiform mole].

AIM: Especially in the first weeks of pregnancy, complete and partial hydatiform moles are not easily detected by sonography, symptoms and clinical signs. Due to the rarity of moles, it is possible that they may be confused with abortive pregnancies until the pathological examination. The aim of this study is to identify the sensitivity, specificity, predictive positive and negative value of the main symptoms and clinical signs of molar pregnancies. METHODS: Thirteen molar pregnancies have been detected after pathological examination from January 2003 to July 2005 in Perugia. Their main clinical signs and symptoms are compared with those recorded in 288 abortive pregnancies, 56 ectopic pregnancies and 27 Hyperemesis gravidarum, observed in the same period. RESULTS: Vaginal bleeding and pelvic pain are the most sensitive symptoms and have the highest predictive negative values. The size of the uterus greater for date is the most specific sign. Pelvic pain with hyperemesis, and uterus size greater for date have the highest predictive positive values, but the lowest sensitivity. CONCLUSIONS: A mole should be excluded in patients with hyperemesis and pelvic pain, and in patients with uterus size greater for date. In the first case, a hyperemesis gravidarum may be diagnosed and, in the second one, a twin pregnancy may be confirmed with a sonographic scan.

Diagnosis, Differential↗

PubMed2002

Detection of chromosomal aneuploidies and gene copy number changes in fine needle aspirates is a specific, sensitive, and objective genetic test for the diagnosis of breast cancer.

Fine needle aspiration cytology is central to the evaluation of clinically or mammographically detected suspicious lesions of the breast. On the basis of results from studies of >500 breast cancers by comparative genomic hybridization we have developed protocols and designed probe sets that allow one to visualize recurrent chromosomal aneuploidies, amplification of oncogenes, and deletion of tumor suppressor genes directly in cytological preparations using multicolor fluorescence in situ hybridization. The fluorescence in situ hybridization probes are specific for chromosome arm 1q, the c-MYC and HER2 oncogenes, the tumor suppressor gene p53 and, as controls for chromosome ploidy of each cell, the centromeres of chromosomes 8, 10, and 17. Application of these diagnostic mixtures to 20 invasive breast cancers, 7 mastopathias, and 2 fibroadenomas demonstrates that a highly sensitive, specific, and objective diagnosis of breast cancer is now possible on cytological preparations obtained by minimally invasive fine needle aspiration.

Aneuploidy↗

PubMed1991

The sensitivity, specificity and predictive value of diagnostic information: a guide for clinicians.

Nurse practitioners and other clinicians use laboratory studies and ancillary tests to confirm or rule out suspected conditions. Deciding which tests to use and interpreting results are essential to the practice of high-quality, cost-effective primary care. A working knowledge of test characteristics and performance facilitates these decisions. This article illustrates how a conceptual understanding of sensitivity, specificity and predictive value applies to daily practice. In addition, the article explains how to evaluate the quality and relevance of literature that reports test performance. While discussion focuses on laboratory tests, the same principles may be applied to the history and physical examination, and to other types of diagnostic data.

AIDS Serodiagnosis↗

PubMed1983

The sensitivity, specificity and predictive value of total plasma protein in the diagnosis of traumatic reticuloperitonitis.

We analyzed the value of total plasma protein in the diagnosis of traumatic reticuloperitonitis in dairy cattle using the concept of sensitivity, specificity and predictive value of a test. Cows with traumatic reticuloperitonitis surgically confirmed at the New York State College of Veterinary Medicine served as cases, while cows surgically explored for other abdominal diseases that might be confused with traumatic reticuloperitonitis during differential diagnosis were controls. The sensitivity of the total plasma protein in diagnosis of traumatic reticuloperitonitis decreased from 97% to 6.3% as the cutoff value for a positive test rose from 65 g/L to 110 g/L, while specificity increased from 11.3% to 99.1% over the same range of cutoff values. Application of these figures to predictive values positive and negative at various prevalence levels of disease is discussed. For example at the measured prevalence level of 37%, 76% of cattle with plasma protein concentrations in excess of 100 g/L had traumatic reticuloperitonitis.

Animals↗

PubMed1991

Specificity, sensitivity and diagnostic predictive value of selected laboratory generated autoantibody profiles in patients with connective tissue diseases.

We tested the hypothesis that the application of 5 laboratory generated serologic profiles facilitates the interpretation of individual autoantibodies in connective tissue diseases without loss of specificity, sensitivity or diagnostic predictive value. The predetermined laboratory generated autoantibody profiles were analyzed in 423 sera from patients with clinically diagnosed connective tissue diseases. All sera positive for one or more autoantibodies to a selected panel of nuclear antigens could be segregated into one of 5 profiles. The distribution of individual autoantibodies and profiles in the sera of patients with various connective tissue diseases were compared in terms of their respective diagnostic predictive value and sensitivity. The application of these profiles improved the sensitivity and diagnostic predictive value of these tests when compared to individual autoantibodies without loss of specificity, thus aiding clinical interpretation.

Antibody Specificity↗

PubMed2001

[Sensitivity, specificity and predictive value of the genetic analysis of SLC3A1 gene variants used for the diagnosis of cystinuria among the spanish population].

OBJECTIVE: To test the clinical usefulness of the analysis of point mutations R452W, M467T, 114C > A, 231T > A, 1136 + 3delT and 1332 + 7T > C in the gene SLC3A1 as well as their possible haplotypes used for the diagnosis of cystinuria in the mediterranean spanish population. MATERIAL AND METHODS: A total of 48 patients with cystinuria, 44 relatives without cystinuria, and 81 healthy controls were studied. A genetic analysis was conducted in order to identify variants in the gene SLC3A1. The sensitivity, specificity, and predictive value for each genetic variant and for the possible haplotypes were calculated. RESULTS: The specificity of mutations M467T, R452W, and 231T > A used for the diagnosis of cystinuria in the general population or for the different subtypes of cystinuria in involved families, was higher than 90%; nevertheless, none of the analysed variants reached a sensitivity higher than 80%. In the study of haplotypes, the highest sensitivity was obtained with the haplotype CTTT (83.8%); however, its specificity and predictive value were low (20.6% and 53.4%, respectively). CONCLUSIONS: The studied genetic variants did not show enough clinical usefulness.

Amino Acid Transport Systems, Basic↗

PubMed1999

Sensitivity, specificity, and predictive values of three Salmonella rapid detection kits using fresh and frozen poultry environmental samples versus those of standard plating.

To reduce human exposure to Salmonella spp. in poultry products, broiler chicken flocks have been tested by culture methods. Since the standard techniques may take 3 to 5 days, rapid detection methods have been developed. In this study we tested the performance of three rapid tests originally developed for food samples by using environmental samples obtained from poultry houses. These rapid tests were Reveal, an enzyme-linked immunosorbent assay from Neogen Corp.; BIND, a bacterial ice nucleation detection method from Idetek Corp.; and a filter monitor method from Future Medical Technologies, Inc. For the standard culture, brilliant green with novabiocin and xylose-lysine-tergitol-4 agar were used for presumptive identification, and identities were confirmed by using poly-O antisera. Environmental samples were collected from farms belonging to an integrated poultry company prior to chick placement and 1 week before slaughter. Sensitivities, specificities, and predictive values with 95% confidence intervals were calculated. Statistical differences were determined by using McNemar's chi square test. The sensitivities of the different tests were not stable, varying widely between sample times, and were affected by freezing of the samples. All of the rapid tests had low sensitivities, which led to many false-negative results. All tests were able to detect Salmonella spp. at a concentration of 10 CFU/ml in at least one of four trials. The BIND and Reveal tests were simple to use with multiple samples and reduced laboratory time by up to 1 day. Based on our results, we do not recommend that any of these rapid tests, in their present state of development, be utilized with environmental samples collected with drag swabs.

Animals↗

PubMed1976

The concepts of sensitivity, specificity and accuracy in evaluation of electrocardiographic, vectorcardiographic and polarcardiographic criteria.

The concepts sensitivity and specificity are critically evaluated in the light of case studies drawn from electrocardiographic literature. These terms are often misused, and the meaning of these elementary statistical concepts is often misunderstood in studies on ECG, VCG and PCG criteria. Specificity figures reported in literature commonly refer to the fraction of true negatives with a negative test in normals. Limiting the test to two-group analysis and eliminating other disease categories tend to give overoptimistic values for specificity and diagnostic accuracy in general. It is pointed out that various performance indices for diagnostic accuracy depend heavily on the composition of the test groups and the fraction of test cases in each group. Sensitivity and specificity appear inadequate performance indices for evaluation of event detection schemes such as classification of ectopic beats. Alternative performance indices are considered, including the error ratio, association index, accuracy of positive test, accuracy of negative test, and overall diagnostic accuracy. Increased utilization of simple statistical tests for significance estimation in ECG criteria evaluation is suggested. The development and application of better diagnostic performance evaluation schemes based on concepts of cost of misclassification, entropy and information is encouraged.

Arrhythmias, Cardiac↗

PubMed2005

Sensitivity, specificity, and variability of nerve conduction velocity measurements in carpal tunnel syndrome.

OBJECTIVE: To explore the diagnostic values of 8 commonly used electrodiagnostic techniques for measuring median nerve conduction velocity (NCV) in carpal tunnel syndrome (CTS). DESIGN: Sensitivity and specificity analyses. SETTING: A hospital-based electrodiagnostic laboratory. PARTICIPANTS: Forty-four normal hands and 136 symptomatic hands. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: (1) Long-segment studies: antidromic wrist-to-digit sensory NCV without subtraction, (2) short-segment studies: transcarpal palm-to-wrist mixed NCV without subtraction, and (3) 2 segment studies: antidromic transcarpal sensory NCV with subtraction (differential calculation from wrist-to-digit and palm-to-digit segments). Both onset and peak latency values were obtained for calculating the NCV. Sensitivity, specificity, and coefficient of variance were calculated for each NCV study. RESULTS: The short-segment, onset latency-based transcarpal mixed NCV yielded the highest sensitivity (75%). CONCLUSIONS: Results from measurement of a single, short-nerve segment tended to be superior to results obtained by either long-segment studies or differential subtraction between 2 segments of the same nerve in the electrodiagnosis of CTS. Explanations for our results are offered from both electrophysiologic and statistical perspectives.

Adult↗

PubMed2001

Autoantibody systems in rheumatoid arthritis: specificity, sensitivity and diagnostic value.

The diagnosis of rheumatoid arthritis (RA) is primarily based on clinical symptoms, so it is often difficult to diagnose RA in very early stages of the disease. A disease-specific autoantibody that could be used as a serological marker would therefore be very useful. Most autoimmune diseases are characterized by a polyclonal B-cell response targeting multiple autoantigens. These immune responses are often not specific for a single disease. In this review, the most important autoantibody/autoantigen systems associated with RA are described and their utility as a diagnostic and prognostic tool, including their specificity, sensitivity and practical application, is discussed. We conclude that, at present, the antibody response directed to citrullinated antigens has the most valuable diagnostic and prognostic potential for RA.

Antibody Specificity↗

PubMedDate not supplied

The sensitivity, specificity and efficiency values of some serological tests used in the diagnosis of paracoccidioidomycosis.

This work reports on the results of double immunodiffusion (ID), counterimmunoelectrophoresis (CIE), complement fixation (CF) and indirect immunofluorescence (IIF) techniques in the serodiagnosis of paracoccidioidomycosis. The study was undertaken on four groups of individuals: 46 patients with untreated paracoccidioidomycosis, 22 patients with other deep mycoses, 30 with other infectious diseases (tuberculosis and cutaneous leishmaniasis) and 47 blood donors as negative controls. Data were obtained using Paracoccidioides brasiliensis antigens, i.e., a yeast culture filtrate for ID, CIE and CF, and a yeast cell suspension for IIF. The sensitivity, specificity and efficiency values were measured according to GALEN & GAMBINO. The gel precipitation tests (ID and CIE) showed the greatest sensitivity (91.3 and 95.6%, respectively), maximum specificity (100%) and the highest efficiency values when compared to the CF and IIF tests.

Complement Fixation Tests↗

PubMed2000

Sensitivity, specificity, and positive predictive value of oral opportunistic infections in adults with HIV/AIDS as markers of immune suppression and viral burden.

OBJECTIVES: The purpose of this study was to assess the use of human immunodeficiency virus (HIV)-related oral opportunistic infections as markers of immune suppression and viral burden in adults with HIV/acquired immunodeficiency syndrome (AIDS). METHODS: The population consisted of a single institution observational cohort involving 606 patients with HIV/AIDS with CD4 count data and 277 with plasma viral load measurements examined between 1995 and 1999 for the presence of oral manifestations of HIV. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value is reported for the association of specific oral lesions and lesion sets with CD4 counts <200 cells/mm(3) and with plasma HIV RNA >/=20,000 copies/mL. RESULTS: Lesions with moderate-to-high PPVs for CD4 <200 cells/mm(3) were as follows: Kaposi's sarcoma (100%; P =.035), pseudomembranous candidiasis (82. 2%; P <.001), linear gingival erythema (70.0%; P =.015), hairy leukoplakia (66.3%; P <.001), angular cheilitis (60.0%; P =.128), and erythematous candidiasis (58.3%; P =.061). Necrotizing ulcerative periodontal diseases, HIV salivary gland disease, oral ulcers, and oral warts had PPVs below 50%. Concurrent infection with candidiasis and hairy leukoplakia had the highest PPV of 89.3%; P <. 001. PPVs for HIV RNA >/=20,000 copies/mL ranged from 27.3% to 100%, with significant association only for pseudomembranous candidiasis. CONCLUSIONS: Specific common oral lesions are strongly associated with immune suppression, as measured by CD4 cell counts, and are modestly associated with high viral burden, thus serving as potential clinical markers of HIV viremia and the consequent destruction of the immune system with progressive HIV disease.

AIDS-Related Opportunistic Infections↗

PubMed1999

Development of a sensitive, specific reverse transcriptase polymerase chain reaction-based assay for epithelial tumour cells in effusions.

We developed a sensitive and specific method for the detection of epithelial cancer cells in effusions with a two-stage molecular-based assay which combined enrichment for cancer cells by immunomagnetic bead selection and reverse transcriptase polymerase chain reaction (RT-PCR) detection of epithelial glycoprotein 2 (EGP-2) RNA. Preliminary experiments indicated that immunobead selection was essential to avoid occasional false-positive RT-PCR results, and this method detected ten breast cancer cells electively added to 10(7) cytologically negative effusion cells. We studied 110 cases of pleural (n = 68) and peritoneal (n = 42) effusions (30 from patients with known carcinoma and 80 from those without known carcinoma), and the results were compared with cytological findings. Of 18 effusions that were cytologically positive or suspicious for malignant cells, 17 (94%) were positive for EGP-2 RNA (the one negative sample was from a patient who recently received combination chemotherapy). Of 92 cytologically negative samples, 11 (12%) were positive for EGP-2, including six patients with a history of previous or current carcinoma. Our method appears to be highly specific and increases the sensitivity of detection of malignant cells; it may be a useful adjunct to routine cytopathological examination.

Ascitic Fluid↗