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PubMed1993

Sensitivity, specificity, and predictability of biopsy interpretations in chronic hepatitis.

BACKGROUND: To determine the frequency of individual histological findings in different types of chronic hepatitis and to assess the sensitivity, specificity, and predictability of histological patterns in distinguishing these types, liver biopsy specimens were examined from 86 patients with autoimmune hepatitis (43 patients), chronic hepatitis B (11 patients), chronic hepatitis C (21 patients), and cryptogenic hepatitis (11 patients). METHODS: Specimens were examined under code by a single hepatopathologist, and predefined histological features were sought. A histological diagnosis was rendered based on composite changes. RESULTS: Patients with chronic hepatitis C had a higher frequency of portal lymphoid aggregates (76% vs. 42%, P = 0.02) and steatosis (52% vs. 16%, P = 0.006) than patients with autoimmune hepatitis, whereas the latter patients more commonly had severe periportal hepatitis (23% vs. 0%, P = 0.02), moderate to severe plasma cell infiltration of the portal tracts (66% vs. 21%, P = 0.005), and lobular hepatitis (47% vs. 16%, P = 0.04). Patients with chronic hepatitis B had a higher frequency of ground-glass hepatocytes (36% vs. 0%, P = 0.001) and multinucleated giant cells (54% vs. 2%, P = 0.0001) than those with autoimmune hepatitis and chronic hepatitis C. The histological diagnoses for these clinical entities had high specificity (81%-99%) and predictability (62%-91%) but low sensitivity (36%-57%). CONCLUSIONS: Autoimmune hepatitis, chronic hepatitis B, and chronic hepatitis C have characteristic individual histological features. Histological patterns based on these features have high specificity and predictability but low sensitivity.

Adult↗
PubMed1983

Fine specificity of the immune response to oxazolones III. Antibodies but not contact sensitivity specific for 2-furyloxazolone are controlled by an Igh-V gene in the mouse.

Early IgM and IgG antibodies of CBA and C3H mice (Igh allotype j) against furyloxazolone (furyl Ox) were found to be heteroclitic, they had a 4-6 times higher affinity for styryloxazolone (styryl Ox) than for furyloxazolone. Anti-furyl Ox antibodies of six other strains (Igh allotypes a, b, c, e, f or g) had approximately 100 times higher affinity for furyl Ox than for styryl Ox. The heteroclitic fine-specificity was inherited as an Igh allotype-linked trait. Furyl Ox-specific contact sensitivity was induced by painting, and its specificity was studied with a recently developed method (Ferreira et al., J. Immunol. 1981. 127:2366). Small strain differences in specificity were detected. They were not inherited as an Igh allotype-linked trait.

Animals↗
PubMed1987

Prevention of perinatal transmission of hepatitis B virus: the sensitivity, specificity, and predictive value of the recommended screening questions to detect high-risk women in an obstetric population.

The Advisory Committee on Immunization Practices recommends that all pregnant women be questioned concerning risk factors for hepatitis B virus infection and that those giving positive responses be serotested. The sensitivity, specificity, and predictive value of those recommended questions among 692 parturient women were determined. A total of 59 currently or previously infected women (hepatitis B surface antigen (HBsAg), antibody to hepatitis B surface antigen (anti-HBs), or antibody to hepatitis B core antigen (anti-HBc) seropositive) were compared with the 633 seronegative women. Among nonwhite women, the sensitivity of a positive response to any one of the recommended questions was 60%. Specificity and positive predictive value were 71% and 19%, respectively. Among white women, the sensitivity, specificity, and positive predictive value were 56%, 75%, and 11%, respectively. To increase such unacceptably low sensitivity, the authors included two additional questions: single marital status and Medicaid/medical assistance payer status. Sensitivity increased to 96% among nonwhite women and 84% among white women. However, a positive response to at least one of the recommended questions or to additional questions was elicited from 78% of all women (92% nonwhite and 64% white). The authors conclude that to prevent perinatal transmission of hepatitis B, we must serotest all women in our obstetric population.

Adult↗
PubMed1999

Effect of pre- and postnatal tobacco smoke exposure on specific sensitization to food and inhalant allergens during the first 3 years of life. Multicenter Allergy Study Group, Germany.

BACKGROUND: The study aimed to assess the effect of pre- and postnatal tobacco smoke exposure on specific sensitization to food allergens and inhalant allergens during the first 3 years of life. METHODS: A total of 342 children of a prospective and observational birth cohort study on atopy (MAS) were included on the basis of a complete follow-up of specific IgE measurements at the ages of 1, 2, and 3 years with available questionnaire information about the parental smoking habit at birth, 18 months, and 3 years of age. Study children were grouped into four exposure categories representing in utero and postnatal environmental tobacco smoke (ETS) exposure, and according to the number of cigarettes smoked by the parents. The effect on the development of allergic sensitization to food, outdoor, and indoor allergens by 3 years of age was determined by multiple logistic regression analyses. RESULTS: At the age of 3, children who were pre- and postnatally exposed to tobacco smoke had a significantly higher risk of sensitization to food allergens (odds ratio: 2.3, 95% C.I.: 1.1-4.6) than unexposed children. Children who were only postnatally exposed by a smoking mother also had a 2.2 times higher risk (95% C.I.: 0.9-5.9) of sensitization than unexposed children. These two categories (pre- and/or postnatal exposure) contribute to the significant overall effect of the tobacco smoke exposure (P< or =0.02). No significant association between tobacco smoke exposure and specific sensitization to inhalant allergens was observed. The determining risk factors for this type of sensitization were atopic family history and mite- and cat-allergen exposure levels. CONCLUSIONS: During the first 3 years of life, both prenatal and postnatal tobacco smoke exposure has an adjuvant effect on allergic sensitization which seems to be restricted to allergens to which children are mainly exposed, in combination with the peak of the ETS exposure around the first birthday.

Child, Preschool↗
PubMed1963

STAPHYLOCOCCAL SENSITIZATION: SPECIFIC BIOLOGICAL EFFECTS OF PHAGE K ON THE BACTERIAL CELL WALL IN LYSIS-FROM-WITHOUT.

Ralston, Doris J. (University of California, Berkeley). Staphylococcal sensitization: specific biological effects of phage K on the bacterial cell wall in lysis-from-without. J. Bacteriol. 85:1185-1193. 1963.-Phage K, shown previously to sensitize staphylococcal-wall mucopeptide to the action of a phage-induced enzyme, virolysin, was found to act in a specific manner in that its sensitizing effects were restricted to chemical linkages affected by three staphylococcal lysins. These caused an immediate lysis, whereas egg-white lysozyme, which could also digest the wall mucopeptide, exerted variable effects, even when in the absence of phage it produced some lysis. Evidence was presented that the K(1) normal cell autolysin and the K phage virolysin could act synergistically with lysozyme on phage-sensitized cells, and that any effects observed with lysozyme were due to the simultaneous presence of trace amounts of these staphylococcal lysins. None of a series of lysozymelike agents from sea urchins, marine sepunculids, and from rabbit peritoneal histiocytes caused accelerated lysis of phage-sensitized cells, although like lysozyme they showed a slow lysis of phage-free living cells. Other enzymes which did not reduce the turbidity of sensitized cells included agents specific for intracellular components (proteins, lipids, nucleic acids), and enzymes, as decarboxylase, alkaline phosphatase, d-amino oxidase, and hyaluronidase. These results suggested that the main effects of the phage in sensitization were limited to areas of the cell wall involved in protection against the action of the staphylococcal lysins.

Animals↗
PubMed1994

Screening for peripheral arterial disease: the sensitivity, specificity, and predictive value of noninvasive tests in a defined population.

Large vessel peripheral arterial disease (LV-PAD) is a common condition that causes significant morbidity and disability. The authors evaluated the individual components of a comprehensive noninvasive vascular examination to identify the most sensitive and specific measurements for diagnosing LV-PAD. This cohort, initially screened between 1979 and 1981 in Rancho Bernardo, California, included 421 normal subjects and 63 subjects with LV-PAD. Segmental blood pressure ratios and flow velocities by Doppler ultrasound were used to define cases of LV-PAD. The sensitivity, specificity, positive predictive value, and negative predictive value of each individual component of the diagnostic algorithm were determined. Overall, measurements of posterior tibial flow showed the highest sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy. In addition, an absent or non-recordable posterior tibial peak forward flow, occurring in 96% of all limbs with isolated posterior tibial disease, or an ankle ratio < or = 0.8 considered in parallel yielded a test with sensitivity of 89%, specificity of 99%, positive predictive value of 90%, negative predictive value of 99%, and overall accuracy of 98%. These results indicate that the vast majority of LV-PAD cases can be detected with a single measurement using a handheld Doppler flowmeter employed at the ankle.

Adult↗
PubMed2004

Prospective study of a real-time PCR that is highly sensitive, specific, and clinically useful for diagnosis of meningococcal disease in children.

Due to the early administration of antibiotics, meningococcal disease is increasingly difficult to diagnose by culturing. Laboratory studies have shown PCR to be sensitive and specific, but there have been few clinical studies. The objectives of this study were to determine the diagnostic accuracy and clinical usefulness of meningococcal PCR through a prospective comparison of real-time PCR, nested PCR, and standard culturing of blood and cerebrospinal fluid (CSF). The setting was a tertiary-care pediatric hospital in Australia, and the participants were 118 children admitted with possible septicemia or meningitis. The main outcome measures-sensitivity, specificity, and positive and negative predictive values-were compared to a "gold standard " fulfilling clinical and laboratory criteria. For 24 cases of meningococcal disease diagnosed by the gold standard, culturing of blood or CSF was positive for 15 (63%), nested PCR was positive for 21 (88%), and real-time PCR was positive for 23 (96%). The sensitivity, specificity, and positive and negative predictive values of real-time PCR (the most sensitive test) for all specimens were, respectively, 96% (95% confidence interval, 79 to 99%), 100% (95% confidence interval, 96 to 100%), 100% (95% confidence interval, 85 to 100%), and 99% (95% confidence interval, 94 to 100%). Of 54 patients with suspected meningococcal disease at admission, 23 had positive PCR results. Only one PCR specimen was positive in a patient thought unlikely to have meningococcal disease at admission. Blood PCR remained positive for 33% of patients tested at up to 72 h. Real-time PCR has high positive and negative predictive values in this clinical setting, with better confirmation of cases than nested PCR. Targeting patients for PCR based on admission criteria appears to be practical, and the test may remain useful for several days after the start of antibiotic administration.

Adolescent↗
PubMedDate not supplied

Can you handle the truth (and know it when you see it)? Understanding sensitivity, specificity, predictive values, and ROC curves.

The interpretation of diagnostic and screening tests requires a basic knowledge of sensitivity, specificity, and predictive values. This article provides an overview of these measures of test performance, a brief description of receiver operating characteristic curves, and relevant illustrations from the medical literature.

Bacteriological Techniques↗
PubMed1991

Rapid method for preparing a beta-glucan-specific sensitive fraction from Limulus (Tachypleus tridentatus) amebocyte lysate.

By separating Limulus amebocyte lysate by cation-exchange chromatography with an SP-Toyopearl 650C column, a fraction insensitive to endotoxin, yet specifically sensitive to beta-glucan, was successfully obtained in the unadsorbed portion. This fraction showed beta-glucan dose-dependent clotting enzyme activity, although no sensitivity to endotoxin. This beta-glucan-dependent reaction showed no interference in the presence of endotoxin, with the fraction also showing sensitivity towards various kinds of beta-glucan, i.e. curdlan, pachyman, laminaran and lichenan. The sensitivity towards curdlan was approximately 10(-10) g/ml.

Animals↗
PubMed2004

The basophil activation test in wasp venom allergy: sensitivity, specificity and monitoring specific immunotherapy.

BACKGROUND: As in vitro diagnosis of wasp venom sensitization by specific serum IgE has a sensitivity of only 60-80%, additional in vitro tests are desirable. Basophil activation is associated with the expression of CD63 and its measurement has been proposed as a novel in vitro test for immediate-type allergy. Furthermore, to date, no in vitro test exists to monitor successful specific immunotherapy (SIT) with wasp venom. Therefore, the potentially harmful sting challenge is still recommended. OBJECTIVE: We compared the CD63-based basophil activation test (BAT) in the diagnosis of wasp venom allergy with skin tests and measurement of specific IgE. Furthermore, we investigated whether BAT can predict the outcome of the sting challenge in patients on SIT. METHODS: Fifty patients with a systemic reaction caused by a wasp sting and 20 controls were studied. Intracutaneous tests were performed with wasp and bee venom in the suspected allergics. Specific IgE was determined by the CAP-FEIA method and basophil activation by flow cytometry upon double staining with anti-IgE/anti-CD63 mAb. Twenty-five patients were sting challenged 6 months after starting SIT and the BAT was repeated before challenge. RESULTS: Sensitivity of the intracutaneous tests, specific IgE and BAT was 100, 76, and 92%, respectively. Specificity of specific IgE and the BAT was 85 and 80%, respectively. The cut-off for a positive BAT was 15% CD63+ basophils. There was a positive correlation between IgE reactivity to wasp venom and the number of CD63+ basophils (r = 0.65). Although no patient had a systemic reaction upon sting challenge, in most subjects basophil activation did not decrease when compared with the BAT before SIT. CONCLUSIONS: Quantitation of basophil activation by CD63 expression is a valuable new in vitro method for diagnosis of allergy to hymenopteran venoms. The CD63-based BAT is a helpful tool for the complementation of routine diagnostic tests such as specific IgE as it increases sensitivity of in vitro detection of sensitization. However, this in vitro method does not offer an alternative to the sting challenge in monitoring successful SIT.

Adolescent↗
PubMed2006

Anxiety sensitivity within the anxiety disorders: disorder-specific sensitivities and depression comorbidity.

The tendency to perceive anxious states as aversive and harmful is hypothesized to confer vulnerability to the development of anxiety disorders. The most commonly used measure of anxiety sensitivity, the Anxiety Sensitivity Index [ASI; Reiss, S., Peterson, R.A., Gursky, D.M., & McNally R.J. (1986). Anxiety sensitivity, anxiety frequency, and the prediction of fearfulness. Behavior Research and Therapy, 24, 1-8], is composed of multiple lower-order factors, assessing fear of physical symptoms, fear of publicly observable anxious symptoms, and fear of cognitive dyscontrol. This study examined the convergent validity of the lower-order anxiety sensitivity dimensions in DSM-IV diagnosed anxiety disorders. Participants with primary diagnoses of panic disorder with agoraphobia, social phobia, and generalized anxiety disorder (GAD) completed the ASI and measures of anxiety and depression severity. Support was found for the convergent validity of all ASI dimensions in reference to thematically related anxiety disorders and in the identification of patients presenting with and without secondary major depressive disorder (MDD). The ASI-fear of cognitive dyscontrol dimension displayed strong and nonredundant associations with GAD, dimensional depression scores, and secondary diagnoses of MDD. The conceptual implications of the shared importance of fear of cognitive dyscontrol in GAD and MDD are discussed.

Adult↗
PubMed1999

Sensitivity, specificity, reliability, and clinical validity of provider-reported symptoms: a comparison with self-reported symptoms. Outcomes Committee of the AIDS Clinical Trials Group.

BACKGROUND: If symptoms are to be recognized and effectively addressed in clinical research, they must be collected using sensitive, specific, reliable, and clinically meaningful methods. OBJECTIVE: To perform a comparison of self-administered symptom survey data with data from conventional provider-reports. DESIGN/METHODS: Secondary data analysis of AIDS Clinical Trials Group Study 081 (ACTG 081), a randomized trial taking place in 33 sites comparing three approaches to prophylaxis for Pneumocystis carinii-related pneumonia that found no difference among treatment arms. The study was performed on 842 subjects with advanced HIV infection. No intervention was undertaken as a result of this study. ACTG 081 included data on functional status, global quality of life and survival, and two methods of symptom measurement: an open-ended, provider-reported symptom assessment (provider-report) and a self-administered symptom survey (self-report). Agreement was measured using kappa scores. Sensitivity and specificity were calculated using self-report as the standard. Reliability was measured by intersite variation and test-retest reliability (8 weeks later). Clinical validity was evaluated by testing expected associations with functional status, global quality of life, and survival. RESULTS: Symptom data were available for 808 patients (96%). Patient and provider agreement was poor (mean kappa, 0.14; range, 0.07-0.25). Compared with self-report, providers underreported the presence and severity of symptoms (mean symptom count, 5.2 versus 1.3; mean severity score, 1.3 versus 0.74). provider-report demonstrated greater variability by site (R2 associated with site, 0.02 versus 0.16) and poorer test-retest reliability (mean kappa, 0.34 versus 0.25). Provider-report severity scores were less strongly associated than were self-report with functional status (chi2, 252 versus 80), global quality of life (R2 for model, 0.57 versus 0.15), and survival (chi2, 38 versus 24). Self-reported symptom severity was strongly correlated to patient-reported global quality of life (p, 0.75; p < .0001). CONCLUSIONS: Provider-reported symptoms as currently collected within the ACTG are less sensitive and reproducible than a self-administered symptom survey. Provider-reported severity scores are also more weakly associated with functional status, global quality of life, and survival. A self-reported symptom survey may provide a better method of symptom measurement for HIV research.

Acquired Immunodeficiency Syndrome↗
PubMed2006

Cardiac troponin I is a sensitive, specific biomarker of cardiac injury in laboratory animals.

This study directly demonstrates that cardiac troponin I (cTnI) is a sensitive, specific, and persistent biomarker in laboratory animals. Histopathological and pathophysiological cardiac changes in dogs, rats and mice correlated with increased serum cTnI with various cardiac inotropic agents, and cardiotoxic drugs and with cardiac arrhythmias, tachycardia, cardiac effusion with dyspnoea, and ageing. A comparison of six immunoassays for cTnI and cardiac troponin T (cTnT) to detect and monitor cardiac injury in a rodent model indicated that enzyme-linked immunosorbent (Life Diagnostics Inc and TriChem Resources Inc, West Chester, Philadelphia, USA) and Immulite (Diagnostic Products Corporation, Llanberis, UK) assays had low sensitivity and less than 1% of the dynamic range of Centaur (Bayer Healthcare Diagnostics, Newbury, UK) cTnI and Elecsys (Roche Diagnostics, Basel, Switzerland) and M8 (Bioveris Europe, Whitney, UK) cTnT assays. In dogs, however, the Immulite assay was effective and correlated with the Centaur. Serum concentrations were highly correlated but 10-fold lower for cTnT compared with cTnI with cardiac injury. Centaur assay also detected cTnI in myocardium from marmosets, swine, cattle, and guinea pigs, indicating it to be candidate cardiac biomarker for these species as well. Purified rat cTnI was 50% more reactive than purified human cTnI in the Centaur assay. In the rat, an age- and gender-dependent variation in serum cTnI was found. Male rats aged six and eight months had a 10-fold greater serum cTnI than age-matched females and three-month-old rats. These increases correlated with minimal histopathological change. Isoproterenol-induced serum cTnI increased up to 760-fold the minimal detectable concentration of 0.07 microg/L, within 4-6 h and decreased with a half-life of 6 h, with an expected return to baseline of 60 h. Severity of histopathological change correlated with serum cTnI during the ongoing injury.

Animal Diseases↗
PubMed1996

Specificity, sensitivity, and predictive value of apolipoprotein-E genotyping for sporadic Alzheimer's disease.

BACKGROUND: We aimed to determine the specificity, sensitivity, and predictive value of apolipoprotein E (APOE) genotyping in 67 consecutive patients with clinical diagnoses of sporadic Alzheimer's disease (AD) who underwent necropsy. METHODS: We studied patients who attended the Duke Memory Disorders Clinic and were diagnosed as having probable AD. These patients were followed up until they died. APOE genotyping was done during life in most cases, but in some brain tissue obtained at necropsy was used. Members of known AD families were excluded. FINDINGS: After neuropathological examination 57 (85%) of 67 of our patients were confirmed as having AD including all 43 who had at least one APOE-epsilon 4 allele. None of the patients found not to have AD carried an epsilon 4 allele. In this series, the specificity of the epsilon 4 allele was 100%, the sensitivity 75%, the positive predictive value 100%, and the negative predictive value 42%. In this necropsy-confirmed series, the epsilon 4/epsilon 4 genotype predicted AD with 100% accuracy. The epsilon 3/epsilon 4 and epsilon 2/epsilon 4 genotypes were also unexpectedly highly specific for AD. INTERPRETATION: Data from hundreds of necropsy-confirmed non-AD patients in other longitudinal necropsy series will allow the predictive value of APOE genotypes to be assessed with useful confidence limits.

Alleles↗
PubMed2005

Is immunotherapy-induced birch-pollen-specific IgG4 a marker for decreased allergen-specific sensitivity?

BACKGROUND: The role of IgG4 during allergen-specific immunotherapy (SIT) is still controversial. The available studies present paramount differences in in vitro techniques, allergens, and clinical outcome parameters. By implementing a sensitive method, and pivotal clinical outcome parameters, we wanted to ascertain the utility of IgG4 as a clinical marker of decreased allergen-specific sensitivity to a common aeroallergen. METHODS: Sera were drawn from 23 birch-pollen-allergic patients during a placebo-controlled clinical trial on birch pollen SIT. Seventeen patients received active treatment. Blood samples were drawn at 0, 2, 4, 7, and 30 treatment weeks, and 36 months. The binding activity of autologous IgG, IgG4, IgE, and IgE- and/or IgG-depleted serum to (125)I-labelled recombinant Bet v 1 was assessed in a fluid-phase radioimmunoassay. Disease severity was assessed subjectively on a visual analogue scale (VAS), and objectively by intradermal late-phase reaction diameters. RESULTS: Before SIT IgG4 fraction of IgG-allergen binding varied from 4 to 74%, with a median of 36%, increasing to 71% after 36 months. Changes in IgG4 or IgG4/IgG fraction were not correlated to clinical outcome parameters. Changes in IgG allergen binding and VAS were significantly correlated (sigma = 0.72; p < 0.05). SIT increased the serum-blocking activity of IgE allergen binding from 25% before SIT to 80% after SIT. No changes were observed in the placebo group. CONCLUSION: The data suggest that IgG4 per se is a poor marker of decreased allergen-specific sensitivity to birch pollen, both as a single measurement and as delta values.

Betula↗
PubMed1987

Sensitivity, specificity and predictive accuracy of Q wave, QX/QT ratio, QTc interval and ST depression during exercise testing in men with coronary artery disease.

One hundred forty-three subjects (107 with coronary artery disease [CAD], 23 without CAD [evaluated by coronary angiography] and 13 athletes) were selected for this study. All subjects underwent exercise testing to evaluate sensitivity, specificity and predictive value of Q wave, QX/QT ratio, QTc interval and ST depression. The Q-wave analysis revealed less sensitivity (49%) and less specificity (83%) than ST depression (71% and 97%, respectively). The QTc criterion had greater sensitivity (80%) than ST depression but less specificity (11%). The QX/QT criterion was no different in sensitivity (74%) but had less specificity (69%). To establish the statistical evaluation of the positive predictive value in CAD, variations in the prevalence of the disease were considered. A 90% prevalence gives the best positive predictive value on all evaluated measurements, between 100% for ST depression and 89% for the QTc criterion. A 5% prevalence, however, gives an acceptable positive predictive value only on ST-segment depression (57%).

Adolescent↗