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Results for “Sensitivity and Specificity”

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PubMed2005

Allergen-specific sensitization in asthma and allergic diseases in children: the study on farmers' and non-farmers' children.

BACKGROUND: Farmers' children are less frequently sensitized to common allergens than the non-farmers' children, but less is known about their sensitization to other allergens and its association with clinical diseases. OBJECTIVE: To examine the association of farm environment with atopic sensitization, allergic diseases, expression of allergen-induced symptoms, and the importance of specific sensitization against 'common' (timothy, dog, cat, birch, Dermatophagoides pteronyssimus, mugwort) and 'other' (cockroach, horse, Lepidoglyphus destructor, cow) allergens for asthma and allergic diseases in children. METHODS: A cross-sectional study including 344 farmers' and 366 non-farmers' children aged 6-13 years in eastern Finland, using a self-administered written questionnaire and skin prick tests against the above-mentioned allergens. RESULTS: Farmers' children had less asthma and allergic diseases and were less often sensitized against common allergens than the non-farmers' children. However, little difference was observed in sensitization against the other allergens between the farmers' (17.2%) and non-farmers (14.5%) children [adjusted odds ratios (aOR) 1.11 (0.71-1.72)]. Being sensitized against only other allergens, without sensitization against common allergens, was unrelated to asthma or allergic diseases. Among the single allergens, sensitization against pets or pollen, or against horse or cow, had the strongest association with asthma, hayfever, and atopic eczema; no such association was seen in D. pteronyssimus, mugwort, cockroach, or L. destructor. Farmers' children had significantly less often symptoms of allergic rhinitis in contact with dog (aOR 0.32%, 95% confidence interval (CI) 0.15-0.67), cat (aOR 0.45, 0.22-0.88), or pollen (aOR 0.58%, 95% CI 0.37-0.90) than the non-farmers' children. CONCLUSION: Farm environment reduces the occurrence of asthma, allergic diseases, and atopic sensitization in children, and also the occurrence of allergen-induced rhinitis. Remarkable differences were observed between single allergens in their association with allergic disease, stressing the importance of allergen selection when defining atopy in epidemiological studies.

Adolescent↗

PubMed1987

Sporadic vs familial classification given etiologic heterogeneity: I. Sensitivity, specificity, and positive and negative predictive value.

Environmental factors are etiologically important in many non-Mendelian familial disorders in man. Because such disorders often occur as "sporadic" cases, (ie, an affected individual with no affected relatives), it is tempting to assume that such cases represent an "environmental" form of the disorder. This paper presents an evaluation of the sensitivity, specificity, and positive and negative predictive power (PPV and NPV) of this "sporadic vs familial classification." The model assumes etiologic heterogeneity with a subpopulation of cases due to a "major" environmental event acting independent of genotype and the remaining cases resulting from a generalized single major locus (SML). Sibship size is modeled by a truncated negative binomial distribution. For rare disorders, this classification has high sensitivity and NPV but low specificity and PPV. As the disorder becomes more common, sensitivity and NPV fall while specificity and PPV rise. The power of the method increases substantially with increasing sibship size up to four or five, but further increases in power are minimal. MZ twins add considerable power to the method but aunts and uncles add little if anything. Both a correlational (phi) and an agreement-based (kappa) statistic indicate that, under most realistic circumstances, the relationship between etiology and family history is modest.

Alleles↗

PubMed1989

Sensitivity, specificity and positive predictive value of selected clinical signs and symptoms associated with schistosomiasis mansoni.

The signs and symptoms classically associated with Schistosoma mansoni infection were analysed in relation to their sensitivity, specificity and positive predictive value in identifying S. mansoni patients as well as more severe forms of the disease under field conditions. Data was collected in a survey conducted in a small urban area in the south east of Brazil (14.3% infection in the studied sample with a geometrical mean excretion of 95.5 S. mansoni eggs/gram of faeces). 'Blood in the stool' and a 'palpable and hardened liver' showed the highest positive predictive value; their presence, even in relatively low prevalence areas may be used by the health field workers as an indication of the existence of more advanced clinical forms of the disease.

Brazil↗

PubMed1988

Screening for glaucomatous visual field defects: the relationship between sensitivity, specificity and the number of test locations.

The visual field results from 104 eyes with early glaucomatous loss and 1860 normal eyes have been used to derive the relationship between sensitivity, specificity and the number of test locations in a visual field screening test. A logarithmic relationship was found between sensitivity and the number of test locations and a linear relationship between specificity and the number of test locations. The results indicate that large numbers of test locations are not required to reach high levels of sensitivity and that clinically it might be better to screen all patients with a few stimuli quickly than to examine carefully those patients who meet a precondition such as raised intraocular pressure or abnormal disc appearance.

Computers↗

PubMed1989

Sensitivity, specificity, and positive predictivity of the Hemoccult test in screening for colorectal cancers. The University of Minnesota's Colon Cancer Control Study.

Data are presented on the sensitivity, specificity, and positive predictivity of the Hemoccult test based on the experience of the Minnesota Colon Cancer Control Study, a randomized clinical trial to determine whether the use of the Hemoccult test can reduce mortality from colorectal cancer. Rehydrating the slides with a drop of water before processing resulted in an increase in positivity (2.4% to 9.8%), and sensitivity (80.8% to 92.2%) but a decrease in specificity (97.7% to 90.4%) and positive predictivity (5.6% to 2.2%). The effects of age and sex were also evaluated. The test was less specific for men than women (p = 0.03). Specificity was highest for those less than 60 yr of age and decreased with increasing age (p = 0.05). The positive predictivity increased with age from 1.6% for those under 60 yr to 3.6% for those over 70 yr (p = 0.0004).

Age Factors↗

PubMedDate not supplied

Forensic drug testing for opiates. IV. Analytical sensitivity, specificity, and accuracy of commercial urine opiate immunoassays.

Four commercial immunoassays, TDx Opiates (TDx), Coat-A-Count Morphine in Urine (CAC), Abuscreen Radioimmunoassay for Morphine (ABUS) and Emit d.a.u. Opiate Assay (EMIT), were tested for sensitivity, specificity, and accuracy with urine specimens containing known amounts of opiates and opiate metabolites. The immunoassays were evaluated in a semiquantitative mode by comparison of morphine equivalents to GC/MS assay of free and total morphine and codeine or to target concentrations. In all cases, the apparent sensitivities of the assays were higher than those required for detection of morphine at cutoffs mandated by the Health and Human Services guidelines for testing of Federal workers. The apparent specificities of the immunoassays varied considerably. The CAC assay was found to be highly selective for free morphine, whereas TDx, ABUS, and EMIT demonstrated broad cross-reactivity with other opiates. Comparison of semiquantitative results from the immunoassays with GC/MS data indicated a high degree of accuracy for determination of morphine levels. Generally, the patterns of sensitivity and cross-reactivity were unique for each assay, indicating that a detailed knowledge of assay performance characteristics is necessary for accurate interpretation of forensic urine testing data.

Forensic Medicine↗

PubMed1997

Routine measurement of IgM, IgG, and IgA rheumatoid factors: high sensitivity, specificity, and predictive value for rheumatoid arthritis.

OBJECTIVE: To determine the isotype specificity and clinical utility of routine testing by ELISA of IgM, IgG, and IgA rheumatoid factors (RF). METHODS: The test was performed on 619 individual specimens: blood bank donors (n = 130); rheumatoid arthritis (RA, n = 139); connective tissue diseases (CTD, n = 71); miscellaneous rheumatic disorders (MRD, n = 91); and 188 consecutive clinical laboratory specimens that tested positive by latex agglutination. Rabbit IgG was used as the antigen attached to the solid phase, and rabbit IgG antibody-enzyme conjugates against IgM (Fc5mu), IgG[F(ab')2], and IgA (alpha chain) were used, respectively, to detect IgM, IgG, and IgA RF. The serum was digested with pepsin to facilitate the measurement of IgG RF. RESULTS: All 3 isotypes were specifically identified; IgM RF was destroyed by pepsin and IgG RF was specifically measured, without interference from IgA RF. Using data obtained from 98 RA specimens and 162 disease controls, the 3 main clinical variables--sensitivity, specificity, and predictive value--were stratified according to 3 combinations of RF isotypes: IgM only (91, 76, and 62%); IgM+IgA (79, 89, and 80%), and IgM+IgG+IgA (53, 99, and 96%). For patients with the 3 isotypes plus > 150 U of IgM and/or IgA the clinical variables were 70, 97, and 93%. In patients with RA the IgG RF was found only in association with IgM RF, i.e., there was no "hidden" RF, and IgA RF was always accompanied by IgM RF. There was a continuous decline in all 3 RF isotypes during treatment with gold salts. The sensitivity of ELISA for IgM RF exceeded that of nephelometry or latex agglutination. CONCLUSION: Routine measurement of IgM, IgG, and IgA RF by ELISA with rabbit IgG as the antigen and pepsin digestion for the detection of IgG RF provides useful information in the differential diagnosis of patients with arthritis.

Antibody Specificity↗

PubMedDate not supplied

Cytologic versus histologic evaluation of needle biopsy of the lung, hilum and mediastinum. Sensitivity, specificity and typing accuracy.

Fine needle aspiration biopsy (FNAB) and punch biopsy (PB) are reliable methods of establishing a morphologic diagnosis in thoracic lesions. However, some reservations exist concerning the diagnostic accuracy of and indications for both methods. Therefore, we evaluated the sensitivity, specificity, typing accuracy and complication rates of both methods. We present a six-year experience with 501 thoracic FNABs and PBs in 482 patients. To examine site-specific differences, we evaluated three different compartments: lung, mediastinum and hilum. In 457 cases the final outcome was known for evaluating the accuracy of the cytologic or histologic diagnoses. FNAB was used most often in lung (81.8%) and hilar lesions (87.3%), whereas PB was used mostly in mediastinal (67.9%) and pleural lesions or if a mesenchymal lesion was suggested radiologically but never in foci below 20 mm in diameter. Our complication rate was 21.3% for FNAB and 4.6% for PB. The most frequent complications were pneumothorax, one hematothorax and intercostal neuralgia. The overall sensitivities of the biopsy methods were equal (FNAB, 98.4%; PB, 98%), but the typing accuracy was better for PB than FNAB (87.2% vs. 83.5%). In the hilum the sensitivities of FNAB and PB were 94.6% and 85.7%, respectively, and for the lungs, 99% and 98.2%. In the mediastinum the sensitivity was 100% for both methods. There were false-positive diagnoses in 5% with FNAB of the lung due to misinterpretation of regenerating epithelium and hamartochondroma and a 0.1% rate of false-negative diagnoses as a result of misplacement of the cannula, leading to inflammation, infarction or scarring. Our data indicate that FNAB is the method of choice in pulmonary and hilar lesions because of the similar diagnostic accuracy. Mediastinal and pleural lesions and presumed mesenchymal tumors should be sampled with PB because the typing accuracy of FNAB is insufficient in these cases.

Adolescent↗

PubMed1994

ALATOP:sensitivity, specificity and predictive value of a new "in vitro" screening test of atopy.

UNLABELLED: The limitations of total IgE for the screening of atopy, gave rise to in vitro multispecific IgE tests to common allergens. These should have an increased sensitivity and specificity when compared to total IgE. Previous data showed the interest of such tests in screening procedures. ALATOP is a new in vitro multispecific IgE test including common aero and food allergens, in liquid phase, for paediatric and adult population. The result is expressed only in positive/negative. The aim of the study was to determine the sensitivity, specificity, positive and negative predictive value and test efficiency, by comparing the results obtained in 266 paediatric patients (selected in our Unit based on a good correlation between clinical history and skin prick tests--SPT), between ALATOP and SPT. RESULTS: 1) Sensitivity: 89.57%; 2) Specificity: 98.06%; 3) Positive predictive value: 98.65%; 4) Negative predictive value: 85.59%; 5) Efficiency of the test: 92.86%; 6) Reproducibility of the test--average: 5.63%. Based on this results and when they are compared to single specific IgE determinations, that are assumed to be about 80% of the sensitivity of SPT, ALATOP showed excellent results, allowing its use in the screening of atopic disease.

Adolescent↗

PubMed1989

Sensitivity, specificity, predictive value and accuracy of film/screen mammography. A three-year experience.

Mammographic and pathologic findings of 312 breast lesions biopsied at the University of Kentucky Medical Center over a three-year period (Jan 1, 1984 through Dec 31, 1986) were correlated. Each of the 312 mammographic examinations was classified as a true positive, true negative, false positive, or false negative interpretation based on the final pathologic diagnosis. The data on 88 wire directed biopsies for clinically occult mammographic lesions and data on 224 biopsies of palpable lesions performed without wire localization were evaluated separately and in combination. From this data the sensitivity, specificity, predictive value, and accuracy of mammography for detecting breast cancer were calculated. Results of all breast biopsies 1984-1986 gave a sensitivity of 84%, specificity of 59%, positive predictive value of 40%, negative predictive value of 92%, and an accuracy of 65% for film-screen mammography. Wire directed biopsies increased the false positive diagnosis from 22 to 96 but also accounted for the detection of 14 clinically occult breast cancers, of which 84% had negative lymph nodes.

Biopsy↗

PubMed1986

[Relation between adrenoreceptor desensitization and their specific sensitivity].

In isolated parts of the rat small intestine, the relationship between desensitization of alpha- and beta-adrenoreceptors and change of their specific sensitivity was studied upon a decrease in noradrenaline content and increase of the incubation medium temperature. An enhancement of the adrenomimetics affinity was always followed by an increase in their ability for desensitization, thus entailing an increased effect of adrenomimetics as the autoinhibitors of adrenergic responses. The dependence of the adrenoreceptors ability for desensitization of their affinity for noradrenaline seems to ensure the control of adrenergic response upon a change in activity of adrenoreceptors.

Animals↗

PubMed2006

A noninvasive, sensitive, specific, and reliable approach to assess whole-body nitric oxide synthesis in children.

Determination of nitric oxide (NO) synthesis in vivo is essential to understand the pathophysiologic role and therapeutic implications of the L-arginine/NO pathway in pediatric diseases. The aim of this study was to establish a noninvasive, sensitive, specific, and reliable approach to determine whole-body NO synthesis in healthy children. Seventeen healthy children (eight boys/nine girls, 4-16 y) were studied twice, and six of them on three occasions. Fasting children received a single oral dose of nonradioactive L-[15N]2-guanidino arginine (5 mg/kg body weight). Complete 24-h urine collections were subsequently performed on an ambulatory basis. Total urinary nitrate excretion and [15N]nitrate enrichments were determined using high-pressure liquid chromatography and gas chromatography-isotope ratio mass spectrometric techniques. The mean urinary [15N]nitrate enrichments on the 0-12-h/12-24-h collection periods of three study visits were 0.9309%/0.5910%, 0.9056%/0.6214%, and 0.9087%/0.6059%. The levels of 24-h urinary [15N]nitrate excretion [mean (95% confidence interval)] for three study visits were 11.70 (8.85-14.54), 12.21 (9.61-14.82), and 11.37 (7.96-14.77) microg [15N]nitrogen-nitrate/mmol creatinine, respectively. Within-subject coefficient of variation for 24-h urinary [15N]nitrate excretion was 11.87%. Agreement among results was assessed by intraclass correlation coefficient (0.93) and coefficient of repeatability (4.08). The percentage of L-[15N]2-guanidino arginine dose directed to nitric oxide synthesis was 0.221% [0.181-0.261]. Multiple regression analysis showed age as the predictor variable of whole-body NO synthesis. These results show for the first time that a single oral administration of L-[15N]2-guanidino arginine can be used to reliably and specifically determine whole-body NO synthesis in children.

Administration, Oral↗

PubMed1995

[The sensitivity, specificity and prognostic values of peripheral secretions in the neonatal intensive unit].

We analyzed cultures (body surface and blood) from 125 infants-64 of them with proved neonatal bacterial sepsis. Isolates from cultures of material from the ear canal, nasopharynx, stomach, endotracheal tube were compared to those recovered from blood. The optimum sensitivity, specificity, and positive predictive values of surface cultures were 40%, 70.6% and 66.7% respectively. We conclude that surface cultures are of limited in predicting the etiology of sepsis in neonates.

Bacteria↗

PubMed2002

Rectal distention testing in patients with irritable bowel syndrome: sensitivity, specificity, and predictive values of pain sensory thresholds.

BACKGROUND & AIMS: Visceral hypersensitivity was detected in patients with functional gastrointestinal disorders and has been proposed as a biological marker of irritable bowel syndrome (IBS). The purpose of this study was to assess the sensitivity, specificity, and the predictive values of pain thresholds evaluated by rectal distention using an electronic barostat in patients with or without IBS and in control subjects. METHODS: Patients were diagnosed according to Rome II criteria. Rectal sensory thresholds were determined in 164 patients (86 IBS patients, 26 painless constipation, 21 functional dyspepsia, and 31 miscellaneous conditions) and in 25 normal controls. All subjects underwent a series of rectal isobaric distentions using an electronic barostat. The bag was progressively distended from 0 to 48 mm Hg and, in response to distention, subjects reported on discomfort or pain. RESULTS: Pain thresholds were lower in IBS patients (30.4 +/- 6.7 mm Hg) compared with controls (44.5 +/- 5), painless constipated (45.4 +/- 5.3), functional dyspepsia (39.4 +/- 7.8), and miscellaneous patients (43.2 +/- 5.5). At the level of 40 mm Hg, the sensitivity of the rectal barostat to identify IBS patients from normal subjects and non-IBS patients was 95.5% and its specificity was 71.8%. The positive predictive value was 85.4%. The negative predictive value was 90.2%. CONCLUSIONS: Lowered rectal pain threshold is a hallmark of IBS patients. Rectal barostat testing is useful to confirm the diagnosis of IBS and to discriminate IBS from other causes of abdominal pain.

Adult↗

PubMed1974

New method of grouping beta-hemolytic streptococci directly on sheep blood agar plates by coagglutination of specifically sensitized protein A-containing staphylococci.

A technique is described that allows the grouping of beta-hemolytic streptococci directly upon the primary colony. This was accomplished by applying a small drop of specifically sensitized protein A-containing Staphylococcus aureus over a colony of streptococci, rocking the plate to allow mixing of the particles with the soluble group-specific polysaccharide, which in the case of beta-hemolytic streptocicci was produced in abundance during colony formation, and observing for agglutination of the sensitized particles. Such a simple test for group A beta-hemolytic streptococci should allow accurate identification of group A streptococci in small laboratories, such as in clinics or physicians' offices, as well as in the larger public health and private laboratories.

Agar↗

PubMed1995

Minimal basal activity and lack of metal-induced activation of the metallothionein gene correlates with lobe-specific sensitivity to the carcinogenic effects of cadmium in the rat prostate.

Metallothionein (MT), a high-affinity metal-binding protein, is known to detoxicate cadmium and may play an important role in cadmium carcinogenesis. In the rat, the ventral lobe of the prostate is sensitive to cadmium carcinogenesis, while the dorsolateral lobe is refractory. The possibility exists that the basis of this lobe-specific sensitivity may lie in the expression of the MT gene. Thus, the expression of the MT gene in lobes of the rat prostate was studied and, for comparative purposes, the expression of the MT gene in the liver, a tissue with well-defined high activity, was also assessed. MT gene expression was determined using a cDNA probe specific for MT-I, oligonucleotide probes specific for MT-I and MT-II, and an assay for cadmium-binding protein capacity. Basal levels of MT-I mRNA and cadmium-binding protein were much less in the ventral prostate than in the liver or dorsolateral prostate. Cadmium, given at a dose known to induce tumors of the ventral prostate (2.5 mumol/kg, sc), did not result in an increase in MT gene expression in the ventral prostate, as assessed by cadmium-binding protein levels or MT-I mRNA, over 72 hr. Small elevations of cadmium-binding protein capacity were detected at high doses of cadmium (25 and 40 mumol/kg) in the ventral prostate but no corresponding increases in MT mRNA were seen. In sharp contrast, hepatic MT gene expression was highly activated throughout the dosage range. Dose-response analysis 24 hr after cadmium administration (0.25 to 40 mumol/kg, sc) showed that MT-I and MT-II mRNA levels were increased in liver in a dose-dependent manner, while no evidence was found for MT gene activation in ventral prostate. In the dorsolateral prostate the high basal activity of the MT gene was shown, as assessed by MT-I and MT-II mRNA levels, which was not further elevated by cadmium treatments. Cadmium accumulation was much lower in the ventral prostate than in the liver. However, levels of cadmium that were sufficient to activate the hepatic MT gene had, in fact, reached the ventral prostate. Thus, the poor basal expression and lack of activation of the MT gene within the ventral lobe of the rat prostate may be the genetic basis to this tissue's sensitivity to the carcinogenic effects of cadmium.

Animals↗

PubMed1989

[The determination of the specific sensitization of the peripheral blood leukocytes in pulmonary tuberculosis patients].

The results of testing blood specimens from patients with pulmonary tuberculosis with the method of diagnosing specific sensitization of leukocytes according to V. A. Fradkin and the method modified by the author are compared. Inhibition of the phagocytic activity of blood neutrophils in response to tuberculin was estimated with the routine procedure. BCG vaccine was used as the test culture. The proposed method revealed the neutrophil sensitization in 88.4 per cent of the patients with infiltrative tuberculosis of the lungs of 6-month duration. With the Fradkin method, the neutrophil sensitization was detected in 77 per cent of the same patients.

Chronic Disease↗

PubMed2000

The sensitivity, specificity, and positive predictive value of screening mammography and symptomatic status.

OBJECTIVE: To examine whether the accuracy of screening mammography varies according to symptomatic status reported at the time of screening. SETTING: Victoria, Australia, where free biennial screening is provided to women aged 40 and older. METHODS: We examined the sensitivity, specificity, and the positive predictive value of screening mammography by symptom status in 106,826 women from Victoria, who attended for first round mammography in 1994 and who did not have a personal history of breast cancer. Symptomatic status was divided into the following categories: asymptomatic; significant symptoms, if the woman reported a breast lump and/or blood stained or watery nipple discharge; and other symptoms, if reported. Unconditional logistic regression modelling was used to adjust for age, use of hormone replacement therapy (HRT), and family history. RESULTS: Sensitivity was lower for women with other symptoms (60.0%) than asymptomatic women (75.6%), or women with significant symptoms (80.8%). Specificity was lower for women with significant symptoms (73.7%) than asymptomatic women (94.9%), or women with other symptoms (95.4%). Among women who had invasive cancer detected during screening interval, women with other symptoms were more likely to get a false negative result (odds ratio 1.79, 95% confidence interval 1.03 to 3.04) than asymptomatic women, after adjusting for age, use of HRT, and family history. CONCLUSION: The lower sensitivity in women with other symptoms requires further investigation. Possible explanations include increased breast density and poor image quality. The high sensitivity in women with significant symptoms is probably due to more cautious radiological practice, which has also resulted in low specificity in this group.

Adult↗