false positive

假阳性
  • 文章类型: Journal Article
    2016年底,在我们的三级保健医院通过侧流测定(LFA)发现了一些假阳性低血清隐球菌抗原(SCrAg)报告。在召回和纠正试剂中的问题后,我们从2017年1月至2023年10月研究了SCrAgLFA≤1:10的意义。在20例患者中,SCrAgLFA≤1:10的31例,14例患者(70%)被归类为真阳性,四个(20%)是不确定的,只有两名(10%)患者是假阳性。如果检测到新的SCrAgLFA≤1:10,应该重复,和额外的工作应该继续进行。
    我们研究了2017年1月至2023年10月低血清隐球菌抗原滴度(SCrAg)LFA≤1:10的意义。在20例SCrAgLFA≤1:10的患者中,只有2例(10%)是假阳性。如果检测到新的SCrAg≤1:10,应该重复,应该做额外的工作。
    Several false positive low serum cryptococcal antigen (SCrAg) reports by lateral flow assay (LFA) were identified in late 2016 at our tertiary care hospital. After the recall and correction of the problem in the reagent, we studied the significance of SCrAg LFA ≤ 1:10 from January 2017 to October 2023. Of 20 patients with 31 samples of SCrAg LFA ≤1:10, 14 patients (70%) were classified as true positives, four (20%) were indeterminate, and only two (10%) patients were false positives. If a new SCrAg LFA ≤1:10 is detected, it should be repeated, and additional workup should be pursued.
    We studied the significance of low serum cryptococcal antigen titer (SCrAg) LFA ≤ 1:10 from January 2017 to October 2023. Of 20 patients with SCrAg LFA ≤1:10, only two patients (10%) were false positives. If a new SCrAg ≤1:10 is detected, it should be repeated, and additional work up should be done.
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  • 文章类型: Journal Article
    背景:气胸(PNX)是急诊科(ED)的常见临床疾病,需要及时的识别和治疗。经胸超声(TUS)在PNX诊断中的作用仍存在争议。我们旨在前瞻性评估TUS在ED中自发性PNX检测中的准确性。方法:该研究共纳入了637名连续的成年患者,他们在四家意大利医院的ED中抱怨急性发作的胸痛和呼吸困难。排除标准是以前的创伤事件,疼痛/呼吸困难的心源性原因和可疑的张力PNX。没有“肺滑动”(B模式)和“条形码”符号(M模式)被认为是TUS中PNX的指示。准确性,灵敏度,特异性,以及阳性和阴性预测值(PPV,NPV)是使用胸部CT扫描作为参考计算的。结果:93例患者发生自发性PNX,83例(89.2%)被TUS正确识别。然而,306例TUS疑似PNX患者未通过胸部CT确诊。TUS期间没有“肺滑动”和“条形码”标志的诊断准确性为50.4%(95%CI:46.4-54.3),敏感性为89.2%(95%CI:81.1-94.7),特异性为43.8%(95%CI:39.5-48.0),PPV为21.3%(95%CI:19.7-23.1),NPV为96.0%(95%CI:92.9-97.7).结论:TUS在鉴定EDs中PNX方面具有较高的敏感性,但特异性较低。在ED设置中完全依靠TUS结果进行患者管理既不适合也不值得推荐。TUS检查可有助于加强PNX的临床怀疑,但其结果应通过胸部X光或CT扫描证实。
    Background: Pneumothorax (PNX) represents a common clinical condition in emergency departments (EDs), requiring prompt recognition and treatment. The role of transthoracic ultrasounds (TUSs) in the diagnosis of PNX is still debated. We aimed to prospectively evaluate the accuracy of TUSs in the detection of spontaneous PNX in EDs. Methods: A total of 637 consecutive adult patients who presented to the EDs of four Italian hospitals complaining of acutely onset chest pain and dyspnoea were included in the study. Exclusion criteria were previous traumatic events, cardiogenic causes of pain/dyspnoea and suspected tension PNX. The absence of \"lung sliding\" (B-mode) and the \"bar-code\" sign (M-mode) were considered indicative of PNX in a TUS. Accuracy, sensitivity, specificity, and positive and negative predictive values (PPVs, NPVs) were calculated using a chest CT scan as reference. Results: Spontaneous PNX occurred in 93 patients: of those, 83 (89.2%) were correctly identified by TUSs. However, 306 patients with suspected PNX at TUS were not confirmed by chest CTs. The diagnostic accuracy of both the absence of \"lung sliding\" and \"bar-code\" sign during TUS was 50.4% (95% CI: 46.4-54.3), sensitivity was 89.2% (95% CI: 81.1-94.7), specificity was 43.8% (95% CI: 39.5-48.0), the PPV was 21.3% (95% CI: 19.7-23.1) and the NPV was 96.0% (95% CI: 92.9-97.7). Conclusions: TUS showed high sensitivity but low specificity in the identification of PNX in EDs. Relying exclusively on TUSs results for patients\' management in ED settings is neither suitable nor recommendable. TUS examination can be useful to strengthen the clinical suspicion of PNX, but its results should be confirmed by a chest X-ray or CT scan.
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  • 文章类型: Journal Article
    被动声学监测可以是监测野生动物种群的有效方法,这些野生动物种群在声学上活跃,但难以通过视觉进行调查,但是在录音中识别目标物种呼叫并不简单。机器学习(ML)技术可以快速进行检测,但可能会错过呼叫并产生误报,即,错误地将来自其他来源的呼叫识别为来自目标物种。虽然丰度估计方法可以有效地解决前一个问题,处理假阳性的方法研究不足。我们提出了一种声学空间捕获-再捕获(ASCR)方法,该方法通过将物种身份视为潜在变量来处理假阳性。ML技术的个体级输出被视为随机变量,其分布取决于潜在身份。这产生了我们最大化的混合模型似然性来估计呼叫密度。我们将我们的方法与现有方法进行了比较,将其应用于ASCR青蛙调查和基于真实长臂猿声学数据的长臂猿模拟声学调查。与广泛使用的假阳性“校正因子”方法相比,我们方法的估计更接近应用于数据集的ASCR,而没有假阳性。模拟表明,我们的方法具有接近零的偏差和准确的覆盖概率,并且比ASCR表现得更好,而不会考虑误报。
    Passive acoustic monitoring can be an effective way of monitoring wildlife populations that are acoustically active but difficult to survey visually, but identifying target species calls in recordings is non-trivial. Machine learning (ML) techniques can do detection quickly but may miss calls and produce false positives, i.e., misidentify calls from other sources as being from the target species. While abundance estimation methods can address the former issue effectively, methods to deal with false positives are under-investigated. We propose an acoustic spatial capture-recapture (ASCR) method that deals with false positives by treating species identity as a latent variable. Individual-level outputs from ML techniques are treated as random variables whose distributions depend on the latent identity. This gives rise to a mixture model likelihood that we maximize to estimate call density. We compare our method to existing methods by applying it to an ASCR survey of frogs and simulated acoustic surveys of gibbons based on real gibbon acoustic data. Estimates from our method are closer to ASCR applied to the dataset without false positives than those from a widely used false positive \"correction factor\" method. Simulations show our method to have bias close to zero and accurate coverage probabilities and to perform substantially better than ASCR without accounting for false positives.
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  • 文章类型: Journal Article
    本文首先通过对其四个条件的讨论来描述任何自我实现预言的机制:可信性,employment,就业敏感性,和实现。每个条件用特定于医学背景的示例来说明。描述性说明以自我实现预言的定义和对集体自我实现预言的扩展结尾。第二,然后,规范帐户讨论了医学中自我实现预言的道德相关性。当预测本身改变预测结果以匹配预测(变革性自我实现)时,自我实现的预言通常被认为是有问题的。我认为,自我实现的预言也不会改变结果,但会改变实现结果的方式(可操作的自我实现),具有重大的伦理和认识论后果。因为很难区分,回顾性地,在变革性和操作性自我实现的预言之间,因此在假阳性或真阳性之间,犯错误也变得同样困难。此外,由于预测必然是真的,从来没有错误信号警告可能已经犯了错误。相反,准确性被视为质量保证的标准。因此,自我实现的预言抑制了我们的学习能力,邀请重复和加剧错误。随着自动诊断和预测程序的兴起,以及越来越多地使用机器学习和人工智能来开发预测算法,特别需要注意自我实现的反馈循环。这种自我实现的预言实际上与医学研究和临床实践有关。有了它,研究人员和从业人员可以在任何医疗案例中检测和分析潜在的自我实现机制,并对其伦理和认知意义负责。
    This article first describes the mechanism of any self-fulfilling prophecy through discussion of its four conditions: credibility, employment, employment sensitivity, and realization. Each condition is illustrated with examples specific to the medical context. The descriptive account ends with the definition of self-fulfilling prophecy and an expansion on collective self-fulfilling prophecies. Second, the normative account then discusses the moral relevance of self-fulfilling prophecies in medicine. A self-fulfilling prophecy is typically considered problematic when the prediction itself changes the predicted outcome to match the prediction (transformative self-fulfillment). I argue that also self-fulfilling prophecies that do not change the outcome but change the ways in which the outcome was realized (operative self-fulfillment), have significant ethical and epistemic ramifications. Because it is difficult to distinguish, retrospectively, between a transformative and an operative self-fulfilling prophecy, and thus between a false or true positive, it becomes equally difficult to catch mistakes. Moreover, since the prediction necessarily turns out true, there is never an error signal warning that a mistake might have been made. On the contrary, accuracy is seen as the standard for quality assurance. As such, self-fulfilling prophecies inhibit our ability to learn, inviting repetition and exacerbation of mistakes. With the rise of automated diagnostic and prognostic procedures and the increased use of machine learning and artificial intelligence for the development of predictive algorithms, attention to self-fulfilling feedback loops is especially warranted. This account of self-fulfilling prophecies is practically relevant for medical research and clinical practice. With it, researchers and practitioners can detect and analyze potential self-fulfilling mechanisms in any medical case and take responsibility for their ethical and epistemic implications.
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  • 文章类型: Case Reports
    用于检测特定疟原虫的免疫色谱测试正在发展。抗原。这些测试依赖于使用针对特定靶标的单克隆或多克隆抗体从外周血捕获抗原。我们介绍了一名28岁的男性患者的病例,该患者先前有两次恶性疟原虫疟疾发作史,七个月和三年前得到了适当的治疗。他被转诊到我们的机构,有六天的发烧史,上腹痛,血尿,和呕吐。连续的厚和薄的血涂片显示血寄生虫阴性,但Bioline™疟疾AgP.f/Pan快速试验对Pan(pLDH)带呈阳性。鉴于临床背景和无法在血涂片中观察疟原虫,快速疟疾试验中pLDH阳性带被认为可能是假阳性.随后的测试得出结论,患者正在经历巨细胞病毒(CMV)感染,随着支持性管理的改进,他出院了,没有任何症状。疟疾仍然是热带和亚热带地区的主要公共卫生问题。虽然快速诊断测试对于及时诊断至关重要,报告了由于与其他感染和病症的交叉反应性而导致的假阳性。我们的案例强调了与CMV感染交叉反应的可能性,尽管没有获得病毒活跃复制的直接证据。这种现象会导致对疟疾病例的高估和治疗不当,强调需要仔细解释快速测试结果。
    There is a growing development of immunochromatographic tests for the detection of specific Plasmodium spp. antigens. These tests rely on capturing antigens from peripheral blood using monoclonal or polyclonal antibodies against specific targets. We present the case of a 28-year-old male patient with a history of two previous episodes of Plasmodium falciparum malaria, treated appropriately seven months and three years ago. He was referred to our institution with a six-day history of fever, epigastric pain, hematuria, and vomiting. Serial thick and thin blood smears were negative for hemoparasites, but a Bioline™ Malaria Ag P.f/Pan rapid test was positive for the Pan (pLDH) band. Given the clinical context and inability to visualize Plasmodium in blood smears, the positive pLDH band on the rapid malaria test was considered a possible false positive. Subsequent tests concluded that the patient was experiencing a cytomegalovirus (CMV) infection, which improved with supportive management, and he was discharged symptom-free. Malaria remains a major public health issue in tropical and subtropical regions. While rapid diagnostic tests are crucial for timely diagnosis, false positives due to cross-reactivity with other infections and conditions are reported. Our case highlights the potential for cross-reactivity with CMV infections, although direct evidence of active viral replication was not obtained. This phenomenon can lead to the overestimation of malaria cases and inappropriate treatment, underscoring the need for careful interpretation of rapid test results.
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  • 文章类型: Journal Article
    背景和目的:乳腺癌是全球女性人群中最常见的癌症之一,如果早期诊断,乳腺癌是可以治愈的。因此,在过去的几十年中,乳腺癌筛查成像技术有了很大的发展和调整.除了乳房X线照相术,超声弹性成像成为乳腺癌检测的重要工具。然而,超声弹性成像仍然有其局限性,即,在BIRADS4类别中,假阳性结果的发生率仍然很高。我们研究的目的是确定潜在的假阳性预测因子,并确定影响应变超声弹性成像质量的因素,以评估分类为BIRADS4B的可疑实性乳腺病变。4C,和5.材料和方法:我们在2017年1月至2022年1月期间在蒂米什瓦拉的一家私人医疗中心进行了一项回顾性研究,使用标准化的BIRADS-US词典通过超声弹性描记术分析了1625个实性乳腺病变。结果:我们的研究表明,大多数与错误和过度诊断相关的超声弹性成像因素是由于结节尺寸(OR=1.02每单位增加)。后声阴影(OR=12.26),反应性腺病(OR=6.35),TES评分增加(TES3OR=6.60;TES4OR=23.02;TES5OR=108.24)。关于患者特征,年龄(OR=每单位增加1.09),BMI,(OR=每单位增加1.09),观察到母乳喂养史(OR=3.00)增加了假阳性结果的可能性.另一方面,不太可能是假阳性组的一部分的结节表现出以下特征:规则形状(OR=0.27),均匀稠度(OR=0.42),和无血管性(OR=0.22)。结论:年龄较大,高BMI,有母乳喂养史的患者,那些表现出以下特定结节特征的人最经常与假阳性结果有关:具有后部声阴影和高弹性评分的大肿瘤,伴有反应性腺病。另一方面,同质,形态规则的无血管结节不易误诊。
    Background and Objectives: Breast cancer is one of the most widespread cancers among the female population around the world and is curable if diagnosed in an early stage. Consequently, breast cancer screening imaging techniques have greatly evolved and adjusted over the last decades. Alongside mammography, sonoelastography became an important tool for breast cancer detection. However, sonoelastography still has its limitations, namely, there is still a high occurrence of false positive results in the BIRADS 4 category. The aim of our study is to identify potential false positive predictors and to ascertain the factors influencing the quality of strain ultrasound elastography for the evaluation of suspicious solid breast lesions categorized as BIRADS 4B, 4C, and 5. Materials and Methods: We conducted a retrospective study in a single private medical center in Timisoara between January 2017 and January 2022 analyzing 1625 solid breast lesions by the sonoelastography strain using a standardized BIRADS-US lexicon. Results: Our study showed that most sonoelastography factors linked to incorrect and overdiagnosis were due to a nodule dimension (OR = 1.02 per unit increase), posterior acoustic shadowing (OR = 12.26), reactive adenopathy (OR = 6.35), and an increased TES score (TES3 OR = 6.60; TES4 OR = 23.02; TES5 OR = 108.24). Regarding patient characteristics, age (OR = 1.09 per unit increase), BMI, (OR = 1.09 per unit increase), and breastfeeding history (OR = 3.00) were observed to increase the likelihood of false positive results. On the other hand, the nodules less likely to be part of the false positive group exhibited the following characteristics: a regular shape (OR = 0.27), homogenous consistency (OR = 0.42), and avascularity (OR = 0.22). Conclusions: Older age, high BMI, patients with a breastfeeding history, and those who exhibit the following specific nodule characteristics were most often linked to false positive results: large tumors with posterior acoustic shadowing and high elasticity scores, accompanied by reactive adenopathy. On the other hand, homogenous, avascular nodules with regular shapes were less likely to be misdiagnosed.
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  • 文章类型: English Abstract
    Mysids是与虾/虾和螃蟹密切相关的小型甲壳类动物,但不受原料食品过敏原标签要求的限制。在过去,一种含有日本冶炼物(wakasagi)的加工食品被怀疑在虾/虾和蟹过敏原测试中产生假阳性结果,因为存在食用的霉菌。然而,没有报道的方法来确认mysid的存在.因此,我们开发了一种PCR方法来检测霉菌。所开发的PCR方法对一株菌类有很高的特异性,从虾样本中没有观察到扩增,螃蟹,磷虾,,,,,或者日本的肉。此外,通过这种PCR方法扩增了从日本冶炼内部器官中提取的DNA,测序显示了MysidDNA.这证实了食用后,日本冶炼的内脏器官中仍有霉菌。这种用于mysid检测的PCR方法甚至扩增了含有日本冶炼的加工食品样品,这些样品被怀疑在虾/虾和蟹ELISA中产生了假阳性结果。因此,这种PCR方法将能够检测这种假阳性是由霉菌污染引起的。
    Mysids are small crustaceans that are closely related to shrimp/prawns and crabs but not subject to food allergen labeling requirements for raw materials. In the past, a processed food that contained Japanese smelt (wakasagi) was suspected of producing a false-positive result in shrimp/prawn and crab allergen test because of the presence of consumed mysids. However, there was no reported methods to confirm mysid presence. Therefore, we developed a PCR method to detect mysids. The developed PCR method had high specificity for a mysid species, with no amplification observed from samples of shrimp, crab, krill, mantis shrimp, or the meat of Japanese smelt. In addition, DNA extracted from the internal organs of Japanese smelt was amplified by this PCR method, and sequencing revealed mysid DNA. This confirmed that mysids remained in the internal organs of Japanese smelt following consumption. This PCR method for mysid detection even amplified Japanese smelt-containing processed food samples that were suspected to have produced a false-positive result in shrimp/prawn and crab ELISA. Thus, this PCR method would enable to detect such false positives are caused by mysid contamination.
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  • 文章类型: Journal Article
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  • 文章类型: Journal Article
    一名38岁的甲状腺乳头状癌妇女接受了全甲状腺切除术,然后进行了大剂量放射性碘消融,被要求进行碘131(I-131)全身随访扫描。她的随访扫描显示,右后颈区域下部有局灶性示踪剂积聚。她刺激的血清甲状腺球蛋白和抗甲状腺球蛋白抗体为0.27ng/ml,无法检测到,分别。对患者的进一步临床检查显示同一区域有黑色结痂。患者在服用碘2天前有黄蜂咬伤史。
    A 38-year-old woman with papillary carcinoma of the thyroid who underwent total thyroidectomy followed by high-dose radioiodine ablation was called for Iodine-131 (I-131) whole-body follow-up scan. Her follow-up scan revealed focal tracer accumulation in the lower aspect of the right posterior neck region. Her stimulated serum thyroglobulin and anti-thyroglobulin antibodies were 0.27 ng/ml and undetectable, respectively. Further clinical examination of the patient revealed a black scab in the same region. The patient revealed a history of wasp bite 2 days before iodine administration.
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