Sensitivity and specificity of patient-entered red flags for lower back pain

Background Context

Red flags are questions typically ascertained by providers to screen for serious underlying spinal pathologies. The utility of patient-reported red flags in guiding clinical decision-making for spine care, however, has not been studied.

Performance of Indian Diabetes Risk Score (IDRS) as screening tool for diabetes in an urban slum

BackgroundIndia is diabetic capital of world, with maximum number of diabetic patients. There is large burden of undetected diabetic cases in community. There is increasing risk of diabetes in urban slum, because of illiteracy, lack of awareness, low socioeconomic status and unhealthy life style. Madras Diabetes Research Foundation (MDRF) has developed Indian Diabetes Risk Score (IDRS) to detect undiagnosed Type 2 diabetes. The aim of this article is to study the performance of IDRS as screening tool for undiagnosed cases of Type 2 diabetes and to find the prevalence of undiagnosed Type 2 diabetes in an urban slum.MethodsScreening for diabetes was carried out in an urban slum. The sample size was 155 (assumed prevalence of undiagnosed diabetes 9%). IDRS tool comprising of two modifiable (waist circumference, physical activity) and two non-modifiable risk factors (age, family history) for diabetes was used to assess the risk of diabetes anthropometry data was obtained. Conformation of diabetes was done using blood sugar levels on fasting venous sample.ResultsMean and SD for age of study subjects were 49.68 ± 14.80 years, BMI 26.60 ± 8.51 kg/m², waist hip ratio (females) 0.87 ± 0.06 cm, waist hip ratio (males) 0.95 ± 0.06 cm, waist circumference (females) 89.99 ± 10.95 cm, waist circumference (males) 89.44 ± 10.9 cm. IDRS predicted the risk of diabetes mellitus with sensitivity of 95.12% and specificity of 28.95% in individuals with score >60.ConclusionIDRS can be used as an effective tool for screening undiagnosed diabetes in the community.     

Empirical Likelihood-Based Confidence Interval of ROC Curves

In this article we propose an empirical likelihood-based confidence interval for receiver operating characteristic curves which are based on a continuous-scale test. The approach is easily understood, simply implemented, and computationally efficient. The results from our simulation studies indicate that the finite-sample numerical performance slightly outperforms the most promising methods published recently. Two real datasets are analyzed by using the proposed method and the existing bootstrap-based method.     

A systematic review classifies sources of bias and variation in diagnostic test accuracy studies

ObjectiveTo classify the sources of bias and variation and to provide an updated summary of the evidence of the effects of each source of bias and variation.Study Design and SettingWe conducted a systematic review of studies of any design with the main objective of addressing bias or variation in the results of diagnostic accuracy studies. We searched MEDLINE, EMBASE, BIOSIS, the Cochrane Methodology Register, and Database of Abstracts of Reviews of Effects (DARE) from 2001 to October 2011. Citation searches based on three key papers were conducted, and studies from our previous review (search to 2001) were eligible. One reviewer extracted data on the study design, objective, sources of bias and/or variation, and results. A second reviewer checked the extraction.ResultsWe summarized the number of studies providing evidence of an effect arising from each source of bias and variation on the estimates of sensitivity, specificity, and overall accuracy.ConclusionsWe found consistent evidence for the effects of case–control design, observer variability, availability of clinical information, reference standard, partial and differential verification bias, demographic features, and disease prevalence and severity. Effects were generally stronger for sensitivity than for specificity. Evidence for other sources of bias and variation was limited.     

Preparation of Polyclonal Antibody against Human MxA Protein and Its Specificity to Diversified Myxovirus Resistant Protein A

Objective To study the human myxovirus resistant protein A （MxA）, a specifically induced peptide by interferon I, and to use its level as a diagnostic criterion for viral infections. Methods Anti-MxA antisera from immunized mice were prepared with the expressed MxA protein of pET32a-MxA in E. coli BL-21（DE3）. To confirm the antiserum activity and specificity, the expression product of BL21, wild type MxA pEGFP-CI-wMxA and site-directed mutant MxA pEGFP-Cl-mMxA（N589S） stably transfected 3T3 cells and induced A549 cells were detected by Western blot with the antisera using non-MxA transfected or non-IFN-[3 induced cells, intact A549, NIH 3T3 cells transfected with pEGFP-CI and pET32a （＋）-transformed BL-21 as controls. Results The antisera had specific positive immunoreactivity to the NIH3T3 cells transformed with pEGFP-CI-wMxA and pEGFP-CI-mMxA, INF-β induced A549 cells and BL21 proteins expressed with pET32a （＋）-MxA. The hybridization signals from IFN-β induced A549 cells depended on the IFN-β inducing concentrations. Meanwhile, immunohistochemical assay showed that NIH 3T3 cells with pEGFP-C 1-wMxA and pEGFP-C 1-mMxA had 〉 98% of positive cells at 1：50 dilution of the serum and A549 cells induced by 20 ng/mL IFN-[3 for 48 h showed 95% positive cells. pEGFP-Cl-transfected NIH 3T3 cells were all negative. Conclusion Anti-sera are highly specific to diversified MxAs. The antibody is detectable by Western blot, immunocytochemistry and immunofluorescence assay.     

Comparison of Direct Interview and Family History Diagnoses of Alcohol Dependence

Using data from The Collaborative Study on the Genetics of Alcoholism, we compare direct interview diagnoses of alcohol dependence to those obtained by history from family members. Using a requirement of three or more positive implications by history, the specificity, sensitivity, and positive predictive values are 98%, 39%, and 45%, respectively.
A logistic analysis found the gender of the relative and alcoholism in the informant to be significant, but not the gender of the informant. The partial odds ratio of a diagnosis at interview associated with a positive family history diagnosis was 13.6. The relationship between the informant and relative was significant, with negative reports from an offspring or mate more influential than a negative report from a parent or second-degree relative.
We derived a recursive equation to combine a variable number of family history reports, wherein the probabilities associated with a single report are computed from the logistic analysis. This permits the use of family history information both as a proxy for an uninterviewed relative, as well as a second source of information to be used in the analysis of genetic family data.     

肺炎支原体抗体联合超敏C反应蛋白检测在小儿支原体肺炎感染诊断中的临床价值

目的 调查研究小儿支原体肺炎感染患者肺炎支原体抗体(MP-Ab)及超敏C反应蛋白(hs-CRP)水平的变化,探讨肺炎支原体抗体与超敏C反应蛋白联合检测对小儿支原体肺炎感染的临床诊断价值.方法 肺炎支原体肺炎患儿110例,对照儿童120例,均按照《诸福棠实用儿科学》中支原体肺炎诊断标准确诊,两组分别进行MP-Ab、hs-CRP检测,肺炎支原体抗体判定以MP-Ab滴度≥1:160为阳性,超敏C反应蛋白判定以hs-CRP＞ 5mg/L为阳性.通过分析MP-Ab检测法与MP-Ab联合hs-CRP检测法敏感性、特异性差异,探讨MP-Ab联合hs-CRP检测法诊断小儿支原体肺炎感染的临床意义.结果 肺炎支原体肺炎患儿组MP-Ab滴度≥1∶160比率高于正常对照组,肺炎支原体肺炎患儿组hs-CRP高于正常对照组,差异均有统计学意义(P＜0.05);MP-Ab检测法诊断肺炎支原体肺炎的灵敏度为78.2％,MP-Ab联合hs-CRP检测法诊断肺炎支原体肺炎的灵敏度为89.1％,MP-Ab联合hs-CRP检测肺炎支原体肺炎的灵敏度高于MP-Ab检测法,差异有统计学意义(P＜0.05);MP-Ab检测法诊断肺炎支原体肺炎的特异度为94.2％,MP-Ab联合hs-CRP检测法诊断肺炎支原体肺炎的特异度为89.2％,差异无统计学意义(P＞0.05).结论 MP-Ab与hs-CRP联合检测能提高小儿支原体肺炎感染的诊断率,具有较高临床价值.     

基于上转化发光免疫层析技术建立发热伴血小板减少综合征病毒总抗体快速检测方法

目的基于上转化发光(UPT)免疫层析技术,建立发热伴血小板减少综合征病毒(SFTSV)总抗体的现场快速检测方法。方法将SFTSV重组NP蛋白与上转化发光颗粒(UCP)偶联,制备UCP-NP免疫层析试纸条,评价该试纸条检测SFTSV总抗体的灵敏性、特异性和稳定性,并检测SFTSV血清254份,与酶联免疫法(ELISA)比较。结果该方法可在15min内完成SFTSV总抗体检测,可检测1∶500稀释度的SFTSV阳性血清,与其他出血热病毒无交叉反应,加样14d内稳定性较高。UPT免疫层析法与ELISA法检测临床血清样品一致性极高(Kappa=0.967),约登指数为0.973。结论建立了基于UPT免疫层析技术的SFTSV总抗体快速检测方法,该方法灵敏、特异,且操作简便、快速,结果稳定,适合在基层门诊和体检现场推广。     

HPV E6/E7 mRNA检测用于ASCUS患者诊断分流的临床研究

目的:探讨人乳头瘤病毒(HPV)E6/E7mRNA检测用于未明确诊断意义的不典型鳞状上皮细胞(ASCUS)诊断结果的判定价值。方法:对160例薄层液基细胞学检查诊断为ASCUS者进行HPV E6/E7mRNA和高危型HPV(HR-HPV)DNA检测,结合病理学诊断资料进行统计学分析。结果:160例中病理结果为宫颈上皮内瘤变Ⅱ级(CINⅡ)及以上级别者的HPV E6/E7mRNA阳性率明显高于CINⅡ以下级别者,差异有统计学意义(P0.05),但与HR-HPV DNA检测结果无统计学差异。HPV E6/E7 mRNA检测CINII及以上级别的灵敏度(69.2%)与HR-HPV DNA检测相比无统计学差异(P0.05);特异度(73.9%)高于HR-HPV DNA检测(61.9%),差异有统计学意义(P0.05)。结论:HPV E6/E7 mRNA检测可作为ASCUS者是否需要进行阴道镜检查的一项指标依据。     

The Assessment of a Rapid Noninvasive Immunochromatographic Assay Test for Fecal Lactoferrin in Patients with Suspected Inflammation of the Ileal Pouch

Purpose

Pouchitis is a common complication after ileal pouch-anal anastomosis. Diagnosis is based on the Pouch Disease Activity Index, which comprises clinical symptoms, endoscopic appearance, and histologic confirmation. A Pouch Disease Activity Index ≥ 7 confirms pouchitis. Fecal lactoferrin is a marker of intestinal inflammation, which can aid in the diagnosis of pouchitis. The IBD EZ VUE? test is a simple, rapid, noninvasive test for fecal lactoferrin. Our goal was to study the sensitivity and specificity of this test in the diagnosis of pouchitis.

Methods

Consecutive patients with pouch dysfunction were recruited from October 2005 to July 2006. A fecal sample was collected before calculation of the Pouch Disease Activity Index. An IBD EZ VUE? test was performed on each fecal sample and the results correlated with the diagnosis of pouchitis to calculate sensitivity and specificity of the IBD EZ VUE? test.

Results

There were 32 patients (21 healthy and 11 inflammed pouches). The IBD EZ VUE? test was positive in 14 patients. It had a sensitivity of 100 percent and a specificity of 86 percent in diagnosing pouchitis. The positive predictive value was 76 percent. There were three false-positive results.

Conclusions

The IBD EZ VUE? test is a sensitive method that may remove the need for invasive pouch investigations and lead to greater confidence when antibiotic therapy is commenced. Further investigations may be reserved for those patients who have a positive lactoferrin test and fail to respond to antibiotic treatment.