[Retroperitoneal schwannoma mimicking colorectal cancer metastases: a false positive result report.] / Schwannoma retroperitoneal simulando metástasis de cáncer colorrectal: reporte de un resultado falso positivo.

Introduction: schwannomas are benign and common soft tissue tumors. They are usually asymptomatic and are discovered for other reasons. Materials: we present the case of an 82-year-old male patient with a recent diagnosis of moderately differentiated adenocarcinoma of the colon and a hypermetabolic periaortic nodule as an incidental finding. Results: percutaneous biopsy of the periaortic nodule confirmed the diagnosis of schwannoma. At one year of follow-up, growth of the schwannoma has been demonstrated. There are no signs of progression of his oncological disease. Conclusions: schwannomas are benign tumors, rarely found in the retroperitoneum and can be sources of false-positive positron emission tomography results.

Introducción: los schwannomas son tumores benignos y frecuentes de las partes blandas. Habitualmente son asintomáticos y son descubiertos por otros motivos. Materiales y métodos: presentamos el caso de un paciente masculino de 82 años con diagnóstico reciente de adenocarcinoma de colon moderadamente diferenciado y con un nódulo periaórtico hipermetabólico como hallazgo incidental. Resultados: la biopsia percutánea del nódulo periaórtico confirmó el diagnóstico de schwannoma. Al año de seguimiento, se ha demostrado crecimiento del schwannoma. No hay signos de progresión de su enfermedad oncológica. Conclusión: los schwannomas son tumores benignos, infrecuentes en el retroperitoneo y pueden ser fuentes de resultados falsos positivos en tomografía por emisión de positrones.

Pitfalls in the Diagnostic Evaluation of Pheochromocytomas.

Pheochromocytomas and paragangliomas (PPGLs), rare neuroendocrine tumors arising from chromaffin cells, present a significant diagnostic challenge due to their clinical rarity and polymorphic symptomatology. The clinical cases demonstrate the importance of an integrated approach that combines clinical assessment, biochemical testing, and imaging to distinguish PPGLs from mimicking conditions, such as obstructive sleep apnea and interfering medication effects, which can lead to false-positive biochemical results. Although a rare condition, false-negative metanephrine levels can occur in pheochromocytomas, but imaging findings can give some clues and increase suspicion for a pheochromocytoma diagnosis. This expert endocrine consult underscores the critical role of evaluating preanalytical conditions and pretest probability in the biochemical diagnosis of PPGLs. Moreover, a careful differentiation of PPGLs from similar conditions and careful selection and interpretation of diagnostic tests, with focus on understanding and reducing false positives to enhance diagnostic accuracy and patient outcomes, is crucial.

Hallazgos mastográficos benignos que simulan malignidad: un dilema diagnóstico / Benign mammographic findings that simulate malignancy: a diagnostic dilemma

Resumen OBJETIVO: Identificar los principales hallazgos histopatológicos benignos y determinar la tasa de falsos positivos que suelen causar conflicto al categorizar las mastografías en el sistema BI-RADS por su aspecto, que puede simular un proceso maligno. MATERIALES Y MÉTODOS: Estudio de cohorte, retrospectivo, efectuado en pacientes atendidas en la Unidad Médica de Alta Especialidad 4 Luis Castelazo Ayala (2019-2023) con reporte mastográfico alterado o sospecha clínica de malignidad. Para el análisis estadístico se utilizó el programa JASP 2.0 y χ2 para la diferencia de proporciones entre grupos. RESULTADOS: De un grupo de 11,481 pacientes, se reportaron 1643 mastografías alteradas: 444 con reportes falsos positivos, 23 pacientes con sospecha clínica y exclusión de 16 que no cumplieron con los criterios de inclusión establecidos. La muestra poblacional estudiada fue de 451 pacientes. La mayoría permaneció asintomática al momento del estudio (42.1%). El hallazgo histopatológico benigno con mayor prevalencia fue el fibroadenoma y su síntoma más relevante el nódulo palpable. La tasa de falsos positivos fue de 4.3%. CONCLUSIONES: En la actualidad, gracias a la implementación de programas de tamizaje es posible establecer diagnósticos de cáncer de mama en etapas tempranas, aunque con la desventaja que el reporte puede resultar falso positivo y ello dar lugar a incremento de la morbilidad y sobretratamiento. Los estándares internacionales indican que estos no deben sobrepasar el 10%.

Abstract OBJECTIVE: To identify the main benign histopathological findings that often cause conflict when categorizing mastographies in the BI-RADS system due to their appearance, which may simulate a malignant process and false positive rate. MATERIALS AND METHODS: Retrospective cohort study carried out in patients attended at the Unidad Médica de Alta Especialidad 4 Luis Castelazo Ayala (2019-2023) with an altered mastographic report or clinical suspicion of malignancy. For statistical analysis we used the JASP 2.0 programme and χ2 for the difference in proportions between groups. RESULTS: From a group of 11,481 patients, 1,643 altered mastograms were reported: 444 with false positive reports, 23 patients with clinical suspicion and exclusion of 16 who did not meet the established inclusion criteria. The population sample studied was 451 patients. The majority remained asymptomatic at the time of the study (42.1%). The most prevalent benign histopathological finding was fibroadenoma and the most relevant symptom was a palpable nodule. The false positive rate was 4.3%. CONCLUSIONS: Currently, thanks to the implementation of screening programmes it is possible to establish breast cancer diagnoses in early stages, although with the disadvantage that the report may be false positive and this may lead to increased morbidity and overtreatment. International standards indicate that these should not exceed 10%.

Overnight 1-mg Dexamethasone Suppression Test for Screening Cushing Syndrome and Mild Autonomous Cortisol Secretion (MACS): What Happens when Serum Dexamethasone Is Below Cutoff? How Frequent Is it?

OBJECTIVE: To determine the frequency of "invalid" 1-mg overnight dexamethasone (Dex) suppression tests (DSTs) (1-mg DST) on a large series of patients investigated for hypercortisolism and examine the interference of substances and clinical conditions that may explain low serum Dex levels. METHODS: A retrospective analysis of 1300 Dex-controlled 1-mg DST applied to patients screened for Cushing syndrome or mild autonomous cortisol secretion in a single center for which there were identified invalid tests and distinctive characteristics that may have interfered with the outcome. RESULTS: Among all tests, 146 (11.2%) were considered invalid (serum Dex levels <140 ng/dL, 36 [24.7%] of which were undetectable [<19.5 ng/dL]). In the Dex-undetectable group, 17% failed to take Dex correctly, 25% were on glucocorticoids (GCs), and 20% were on anticonvulsants and moderate CYP3A4 inducers. In the remaining 110 tests (serum Dex 20-140 ng/dL), 6.5% did not take Dex or were using GC, 22% were on anticonvulsants or CYP3A4 inducers, and another 13% had previous gastrointestinal tract abnormalities impairing drug absorption. CONCLUSION: Inappropriately low serum Dex levels during the 1-mg DST may lead to false-positive results. This is associated with recurrent use of CYP3A4-inducing drugs and/or gastrointestinal abnormalities. When serum Dex is undetectable, the key reason is failure to take the medication or the use of GC (when cortisol is suppressed). Simultaneous measurement of serum cortisol and Dex allows for DST validation, improving its accuracy and avoiding unnecessary repetitions. Adherence to verbal/written recommendations and actual use of medication are critical for interpreting the test.

Diagnostic Accuracy of Fecal Immunochemical Test (FIT) in Bleed-positive and Bleed-negative Colorectal Cancer (CRC) Among a Cohort of 5,090 Subjects who Participated in the Colorectal Neoplasia (CRN) Screening in Brazil.

BACKGROUND/AIM: This study assessed the diagnostic accuracy (DA) of fecal immunochemical test (FIT) ColonView (CV) and guaiac-based fecal occult blood test (HemoccultSENSA) among bleed-positive (history or signs of intestinal bleeding) and bleed-negative participants (no history or signs of intestinal bleeding) (n=5,090) in colorectal neoplasia (CRN) screening in Brazil. PATIENTS AND METHODS: The eligible patients for the study (n=506) collected three consecutive stool samples, to be analyzed by both assays (CV, SENSA). Finally, 421/5090 (8.3%) patients returned both samples, which were subjected to final analysis. Receiver operating characteristic (ROC) analysis with different cut-offs was performed to assess the DA. RESULTS: The area under curve (AUC) values for i) visually analyzed (VA) CV for bleed-positive CRC, ii) automatically analyzed (AA) CV for bleed-positive CRC, iii) VA CV for bleed-negative CRC, and iv) AA CV for bleed-negative CRC as endpoints were as follows: i) AUC=0.864, ii) AUC=0.933, iii) AUC=0.836, and iv) AUC=0.892. In roccomp analysis, the differences in AUC values were: between i) and ii) p=0.068; between i) and iii) p=0.497; between i) and iv) p=0.488; between ii) and iii) p=0.0058; between ii) and iv) p=0.229; and between iii) and iv) p=0.138. CONCLUSION: This is the first investigation where two modes of CV test, VA, and AA, for bleed-positive and bleed-negative CRC patients were used as the endpoint. The AA reading of the CV test showed higher DA in bleed-positive than in bleed-negative CRC patients.

Risco de resultado falso positivo no rastreamento mamográfico do Brasil / Risk of false-positive result in mammography screening in Brazil / Riesgo de resultados falsos positivos en el cribado mamográfico en Brasil

Resultados falsos positivos na mamografia de rastreamento são comuns a essa intervenção e trazem ônus para as mulheres e o sistema de saúde. O objetivo deste estudo foi estimar o risco de resultado falso positivo no rastreamento mamográfico brasileiro com base em dados de sistemas de informação do Sistema Único de Saúde (SUS). Foi realizado estudo de coorte histórica de mulheres de 40-69 anos, que realizaram mamografia de rastreamento e exame histopatológico de mama no SUS, nos anos de 2017 a 2019. A taxa de resultados falsos positivos foi estimada a partir da prevalência de resultados BI-RADS alterados na mamografia de rastreamento e da proporção de resultados benignos no exame histopatológico de mama. Das 10.671 mulheres com exame histopatológico no SUS, 46,2% apresentaram resultado benigno, sendo essa proporção significativamente maior em mulheres de 40-49 anos comparada à de mulheres de 50-69 anos. A estimativa de resultados falsos positivos foi de 8,18 casos por 100 mulheres na faixa etária de 40-49 anos, e de 6,06 por 100 mulheres na faixa de 50-69 anos. Essas informações são úteis aos gestores na avaliação de programas de rastreamento do câncer de mama, assim como aos profissionais de saúde, para que orientem a mulher sobre as implicações do rastreamento mamográfico.

False-positive results on mammography screening are common, putting a burden on both women and the health care system. This study aimed to estimate the risk of false-positive results in Brazilian mammography screening based on data from the Brazilian Unified National Health System (SUS) information systems. A retrospective cohort study was conducted with women aged 40-69 years, who underwent mammography screening and breast histopathological examination at SUS from 2017 to 2019. The rate of false-positive results was estimated based on the prevalence of altered BI-RADS results on mammography screening and the proportion of benign results on breast histopathological examination. Of the 10,671 women with histopathological examination at SUS, 46.2% had a benign result, and this proportion was significantly higher in women aged 40-49 years compared to women aged 50-69 years. The estimate of false-positive results was 8.18 cases per 100 women aged 40-49 years and 6.06 per 100 women aged 50-69 years. This information is useful for public managers in evaluating mammography screening programs, as well as for health care providers to guide women on the implications of mammography screening.

Los resultados falsos positivos en la mamografía de cribado son comunes en esta intervención y suponen prejuicios para las mujeres y el sistema de salud. El objetivo de este estudio fue estimar el riesgo de resultados falsos positivos en el cribado mamográfico brasileño a partir de los datos del sistema de información del Sistema Único de Salud (SUS). Se realizó un estudio de cohorte histórica de mujeres de 40-69 años, que se sometieron a mamografía de cribado y examen histopatológico de mama en el SUS, de 2017 a 2019. La tasa de resultados falsos positivos se estimó a partir de la prevalencia de resultados de BI-RADS alterados en la mamografía de cribado y la proporción de resultados benignos en el examen histopatológico de mama. De las 10.671 mujeres que se sometieron a examen histopatológico en el SUS, el 46,2% tuvo un resultado benigno, siendo esta proporción significativamente mayor en mujeres de 40-49 años en comparación con las mujeres de 50-69 años. La estimación de resultados falsos positivos fue de 8,18 casos por 100 mujeres en el grupo de edad de 40-49 años y 6,06 por 100 mujeres en el grupo de 50-69 años. Esta información es útil para los gestores en la evaluación de los programas de cribado de cáncer de mama, así como para los profesionales sanitarios en orientar a las mujeres sobre las implicaciones del cribado mamográfico.

Placenta Accreta Spectrum Prenatal Diagnosis Performance: Are Ultrasound False-positive Results Acceptable in Limited-resources Settings? / Desempenho do diagnóstico pré-natal do espectro da placenta acreta: Os resultados falso-positivos do ultrassom são aceitáveis em ambientes com recursos limitados?

Abstract Objective The immediate referral of patients with risk factors for placenta accreta spectrum (PAS) to specialized centers is recommended, thus favoring an early diagnosis and an interdisciplinary management. However, diagnostic errors are frequent, even in referral centers (RCs). We sought to evaluate the performance of the prenatal diagnosis for PAS in a Latin American hospital. Methods A retrospective descriptive study including patients referred due to the suspicion of PAS was conducted. Data from the prenatal imaging studies were compared with the final diagnoses (intraoperative and/or histological). Results A total of 162 patients were included in the present study. The median gestational age at the time of the first PAS suspicious ultrasound was 29 weeks, but patients arrived at the PAS RC at 34 weeks. The frequency of false-positive results at referring hospitals was 68.5%. Sixty-nine patients underwent surgery based on the suspicion of PAS at 35 weeks, and there was a 28.9% false-positive rate at the RC. In 93 patients, the diagnosis of PAS was ruled out at the RC, with a 2.1% false-negative frequency. Conclusion The prenatal diagnosis of PAS is better at the RC. However, even in these centers, false-positive results are common; therefore, the intraoperative confirmation of the diagnosis of PAS is essential.

Resumo Objetivo Recomenda-se o encaminhamento imediato de pacientes com fatores de risco para espectro placentário acreta (PAS, na sigla em inglês) para centros especializados, favorecendo assim o diagnóstico precoce e o manejo interdisciplinar. No entanto, erros diagnósticos são frequentes, mesmo em centros de referência (CRs). Buscou-se avaliar o desempenho do diagnóstico pré-natal para PAS em um hospital latino-americano. Métodos Um estudo descritivo retrospectivo incluindo pacientes encaminhados por suspeita de SAP foi realizado. Os dados dos exames de imagem do pré-natal foram comparados com os diagnósticos finais (intraoperatórios e/ou histológicos). Resultados Foram incluídos 162 pacientes no presente estudo. A idade gestacional mediana no momento da primeira ultrassonografia suspeita de PAS foi de 29 semanas, mas as pacientes chegaram ao CR de PAS com 34 semanas. A frequência de resultados falso-positivos nos hospitais de referência foi de 68,5%. Sessenta e nove pacientes foram operadas com base na suspeita de PAS com 35 semanas e houve 28,9% de falso-positivos no CR. Em 93 pacientes, o diagnóstico de PAS foi descartado no CR, com frequência de falso-negativos de 2,1%. Conclusão O diagnóstico pré-natal de PAS é melhor no CR. Entretanto, mesmo nestes centros, resultados falso-positivos são comuns; portanto, a confirmação intraoperatória do diagnóstico de SAP é essencial.

Critical CHD screening programme: a 3-year multicentre experience in Mexico.

INTRODUCTION: CHDs are the most common type of birth defect. One in four newborns with a heart defect has a critical CHD. In Mexico, there is a lack of data available to determine its prevalence. Pulse oximetry screening programmes have been implemented worldwide, reporting opportunity areas in algorithm interpretation and data management. Our study aims to share preliminary results of a 3-year experience of a multicentre pulse oximetry screening programme that addresses critical challenges. MATERIALS AND METHODS: This retrospective study examined the reports of newborns screened from February 2016 to July 2019 from five hospitals. Two algorithms -the New Jersey and the American Academy of Pediatrics- were implemented over consecutive periods. The algorithms' impact was assessed through the calculation of the false-positive rate in an eligible population. RESULTS: A total of 8960 newborns were eligible for the study; from it, 32.27% were screened under the New Jersey and 67.72% under the American Academy of Pediatrics algorithm - false-positive rate: 1% (CI 95: ± 0.36%) and 0.71% (CI 95: ± 0.21%), respectively. Seventy-nine newborns were referred, six were diagnosed with critical CHD, and six with CHD. The critical CHD estimated prevalence was 6.69:10,000 newborns (CI 95: ± 5.36). Our results showed that the algorithm was not related to the observable false-positive rate reduction. DISCUSSION: Other factors may play a role in decreasing the false-positive rate. Our experience implementing this programme was that a systematic screening process led to more confident results, newborn's report interpretation, and follow-up.

Schwannoma: A rare cause of false-positive 68Ga-PSMA PET/CT uptake in the evaluation of metastatic prostate cancer.

PSMA expression occurs in epithelial cells in both normal and hyperplastic prostates. In adenocarcinoma, it is present in greater intensity, especially in the more aggressive ones. This made it possible to develop diagnostic tools with greater specificity for detecting prostate cancer metastases like the 68Ga-PSMA PET/CT. Several benign neoplasms with increased marker uptake have been described in the literature. Such false-positives are usually associated with soft tissue injuries, abnormal vascular proliferation, neurogenic injuries, thymomas and adenomas. In the present work we present a case report that exemplifies the above.

The Automatically Analyzed (AA) ColonView (CV) Quick Test for Fecal Occult Blood Shows Higher Diagnostic Accuracy in Detection of Colorectal Adenoma than Visually Analyzed Tests.

BACKGROUND/AIM: The present study compared the accuracy of visually analyzed (VA) and automatically analyzed (AA) ColonView (CV) quick test; a new-generation fecal immunochemical test (FIT) for hemoglobin (Hb) and hemoglobin/haptoglobin (Hb/Hp) (Biohit Oyj, Helsinki, Finland) in subjects participating in colorectal neoplasia (CRN) detection in Brazil. A traditional guaiac-based fecal occult blood test (gFOBT) test (HemoccultSENSA) was used as a reference. PATIENTS AND METHODS: A cohort of 509 colonoscopy-referral patients were asked to collect three consecutive fecal samples, to be analyzed by both CV and SENSA. RESULTS: In ROC analysis for the AA reading, the optimal cut-off value for CV Hb was ≥8.0912 and that for CV Hb/Hp was ≥1.8983. With these cut-offs, the sensitivity (Se), specificity (Sp), and efficiency of CV AA in detecting colorectal adenoma (CRA) were: 64.2%/78.6%, 53.4%/35.3%, and 58.6%/56.5%, for Hb and Hb/Hp, respectively. In the HSROC analysis, the AUC values for i) VA and ii) AA modes were as follows: i) AUC=0.551 (95%CI=0.500-0.602), ii) AUC=0.606 (95%CI=0.550-0.662). The difference between these AUC values was statistically significant (p=0.0160). CONCLUSION: The present study confirms the previous results on the applicability of the ColonView quick test in CRN screening. Of the two optional reading modes, the AA reading showed significantly better diagnostic accuracy as compared to the VA reading (or SENSA), in detecting the CRA endpoint in colonoscopy-referral patients.

Statistical Assessment of Discrimination Capabilities of a Fractional Calculus Based Image Watermarking System for Gaussian Watermarks.

In this paper, we explore the advantages of a fractional calculus based watermarking system for detecting Gaussian watermarks. To reach this goal, we selected a typical watermarking scheme and replaced the detection equation set by another set of equations derived from fractional calculus principles; then, we carried out a statistical assessment of the performance of both schemes by analyzing the Receiver Operating Characteristic (ROC) curve and the False Positive Percentage (FPP) when they are used to detect Gaussian watermarks. The results show that the ROC of a fractional equation based scheme has 48.3% more Area Under the Curve (AUC) and a False Positives Percentage median of 0.2% whilst the selected typical watermarking scheme has 3%. In addition, the experimental results suggest that the target applications of fractional schemes for detecting Gaussian watermarks are as a semi-fragile image watermarking systems robust to Gaussian noise.

Falsos positivos del cribado de trisomía 21 y 18 del primer trimestre y complicaciones obstétricas / Adverse outcomes in pregnancies with false positive trisomy 21 and 18 screening results

OBJETIVO: Analizar si los casos positivos de cribado combinado de trisomía 21 (t21) o trisomía 18 (t18) en ausencia de aneuploidía (falsos positivos- FP) se relacionan con complicaciones de la gestación, ajustando por factores demográficos y clínicos de riesgo. MATERIAL Y MÉTODOS: Estudio retrospectivo de casos y controles anidado en una cohorte de pacientes que acudieron para cribado del primer trimestre. Los casos fueron las pacientes con FP de riesgo combinado de t21 superior a 1/270 o riesgo de t18 superior a 1/100. Se consideraron complicaciones de la gestación: óbito fetal, parto prematuro menor de 34 semanas o prematuro menor de 37 semanas, preeclampsia, retrasos de crecimiento, pequeño para la edad gestacional (CIR, PEG) y diabetes gestacional (DG). Se ajustó por obesidad, edad, paridad, tabaquismo, y técnicas de reproducción asistida. RESULTADO: Se obtuvieron 204 casos de FP, 149 FP para trisomía 21, 41 para trisomía 18, y 14 FP para ambos riesgos. Se encontró asociación estadísticamente significativa de FP t21 con óbito fetal (OR=3,5; ic95% 1,4-8,7; p=0,01), parto prematuro menor de 37 semanas (OR=2,2; IC95% 1,4-3,4; p=0,001), preeclampsia (OR =2,6; IC95% 1,17-6,1; p=0,02), PEG (OR =2,2; IC95% 1,2-4,1; p=0,02), CIR (OR=2,8; IC95% 1,6-5,1; p=0,001), y DG (OR=2,1; IC95% 1,2-3,7; p=0,01). Los FP t18 se asociaron con óbito (OR=8,9; IC95% 2,9-27; p=0,002). CONCLUSIÓN: Los FP del cribado del primer trimestre, para trisomía 21 y trisomía 18, se asocian con resultados obstétricos adversos.

We have studied whether positive cases of combined trisomy 21 (t21) or 18 (t18) screening in the absence of aneuploidy (false positives -FP-) are related to pregnancy complications adjusting for demographic and clinical risk factors. METHODS: Retrospective case-control study nested in a cohort of patients who came for first trimester aneuploidy screening. The cases were patients with FP combined risk of t21 (greater than 1/270) or t18 risk (greater than 1/100). The control group was a sample of patients with low-risk screening. We considered pregnancy complications: stillbirth, premature delivery before 34 and 37 weeks, preeclampsia, growth retardation, small for gestational age (FGR, SGA), and gestational diabetes (GD). Or were adjusted for obesity, age, parity, smoking, and assisted reproduction techniques. RESULTS: 204 cases of FP were obtained, 149 FP for trisomy 21, 41 for trisomy 18, and 14 FP for both risks. A statistically significant association between t21 FP was found with stillbirth (OR = 3.5; 95% CI 1.4-8.7; p = 0.01), preterm delivery less than 37 weeks (OR = 2.2; 95% CI 1.4-3.4; p = 0.001), preeclampsia (OR = 2.6; 95% CI 1.17-6.1; p = 0.02), SGA (OR = 2.2; 95% CI 1, 2-4.1; p = 0.02), FGR (OR = 2.8; 95% CI 1.6-5.1; p = 0.001), and GD (OR = 2.1; 95% CI 1.2 −3.7; p = 0.01). FP t18s were associated with fetal loss (OR= 8.9 (95% CI 2.9-27) p = 0.002. CONCLUSION: FP from first trimester screening for t21 and t18 are associated with adverse obstetric outcomes.

Alpha-Defensin Offers Limited Utility in Routine Workup of Periprosthetic Joint Infection.

BACKGROUND: Alpha-defensin (AD) is a synovial biomarker included as a minor criterion in the scoring system for diagnosing periprosthetic joint infection (PJI). The purpose of this study is to study the impact of AD on diagnosis and management of PJI. METHODS: Synovial fluid from 522 patients after total knee and hip arthroplasty was retrospective reviewed. Synovial white blood cell count, percentage of neutrophils, and culture from the AD immunoassay laboratory were reviewed with serum erythrocyte sedimentation rate and C-reactive protein values from our institution. A modified version of the 2018 scoring system for diagnosis of PJI was used, only scoring white blood cell count, percentage of neutrophils, erythrocyte sedimentation rate, and C-reactive protein. AD was then analyzed with these scores to determine if AD changed diagnostic findings or clinical management. RESULTS: Eight-two patients were categorized as "infected" (score ≥6), of which 76 patients had positive AD. Of the 6 "infected" patients with negative AD, 2 had positive cultures (Staphylococcus epidermidis). Two-hundred thirteen patients were diagnosed as "possibly infected" (score 2-5). Fourteen of these patients had positive AD, of which 5 had positive cultures assisting with the diagnosis. The AD test changed the diagnosis from "possibly infected" to "infected" in 8 patients (1.5%) but only altered treatment plan in 6 patients (1.1%). A score <2 (not infected) was calculated in 227 patients with no patients having positive AD. CONCLUSION: AD may be beneficial in some cases where laboratory values are otherwise equivocal; however, its routine use for the diagnosis of PJI may not be warranted.

The effect of transvaginal ultrasound, vaginal examination, or coitus on fetal fibronectin results: individual participant data from 6 cohort studies.

OBJECTIVE: This study aimed to determine whether recent cervical manipulation via transvaginal ultrasound, sterile vaginal examination, or coitus affects the accuracy of fetal fibronectin results. DATA SOURCES: An electronic search was performed in PubMed, Scopus, Embase, Ovid MEDLINE, ClinicalTrials.gov, Cochrane Library, and CINAHL using a combination of pertinent key words from inception to June 2019. STUDY ELIGIBILITY CRITERIA: We included all observational studies that provided individual-level data on fetal fibronectin results after recent transvaginal ultrasound, sterile vaginal examination, or coitus. STUDY APPRAISAL AND SYNTHESIS METHODS: Studies were appraised using the Newcastle-Ottawa Quality Assessment Scale for cohort studies. Individual participant data from the included studies were pooled for each intervention. The primary outcome was agreement between pre- and postmanipulation swabs, estimated using proportion agreement and kappa statistics with 95% confidence intervals. Secondary outcomes included frequency in which the fetal fibronectin result changed after cervical manipulation and percentage of discordant pairs. Baseline fetal fibronectin swabs were not obtained in studies examining coitus; therefore, the results of these articles were examined separately. Outcome data were combined to estimate the relative risk of a positive qualitative fetal fibronectin result after coitus and differences in the concentration of quantitative fetal fibronectin. RESULTS: Of 807 studies identified, 6 were included. Three studies assessed the effect of transvaginal ultrasound (n=346 specimen pairs), 2 of sterile vaginal examination (n=122 specimen pairs), and 2 of coitus (n=262 specimen pairs) on fetal fibronectin results, with 1 study assessing the effect of more than 1 intervention. The proportion agreement between specimen pairs before and after transvaginal ultrasound and sterile vaginal examination was 93.4% (kappa, 0.69; 95% confidence interval, 0.57-0.81) and 88.5% (kappa, 0.69; 95% confidence interval, 0.54-0.84), respectively. For both transvaginal ultrasound and sterile vaginal examination, discordance with a positive preintervention fetal fibronectin and negative postintervention fetal fibronectin occurred more frequently than the converse. Patients reporting coitus within 24 to 48 hours were more likely to have a positive fetal fibronectin result than controls (39.7% vs 7.1%; relative risk, 5.6; 95% confidence interval, 3.0-10.6). CONCLUSION: Cervical manipulation via transvaginal ultrasound or sterile vaginal examination does not significantly affect fetal fibronectin results; therefore, its use after these exposures is clinically acceptable. Conversely, the use of fetal fibronectin in the setting of recent coitus should continue to be discouraged.

Dificultades en la detección de genomas del nuevo coronavirus 2 (SARS CoV-2) / Pandemic and social inequiality: the popular neighborhoods of the Buenos Aires suburbs in preventive social isolation

RESUMEN El manejo de las infecciones virales respiratorias, tanto a nivel nacional como a nivel mundial, requiere resultados científicos de calidad. La reacción en cadena de la polimerasa de transcriptasa inversa (rRT-PCR, por su sigla en inglés) es considerada el "patrón de oro" para detectar el genoma del nuevo coronavirus 2 (SARS-CoV-2), agente causal de la enfermedad por el nuevo coronavirus (COVID-19) sobre todo en la fase aguda de la infección. Su uso es controvertido fuera de un contexto de exposición viral. El objetivo del presente trabajo es analizar escollos encontrados durante la detección del genoma del SARS-CoV-2 que pueden producir resultados falsos. Los falsos negativos de rRT-PCR pueden deberse al momento y la eficacia de la toma de la muestra, la congelación, el almacenamiento y la descongelación, y a la inactivación térmica de la virulencia. Además, las señales retardadas de los controles internos invalidan la negatividad. Por otra parte, las muestras con escaso material biológico llevan a conclusiones negativas falsas, por lo que determinar un umbral (número mínimo de células epiteliales) contribuirá a reducirlas. Sin embargo, la mayoría de los kits detectan ADN humano, pero no fueron calibrados para cuantificar carga celular. Los ácidos ribonucleicos nucleares (ARN) virales adheridos a guantes, tubos y gorros, -entre otros elementos-, son fuente de falsos positivos. Las farmacopeas sugieren que la contaminación externa se controle en series de 100 muestras con al menos una representatividad del 10%. Si se extrapola esta aproximación al laboratorio de análisis clínicos, en lugar de uno se deberían procesar al menos 10 controles negativos contiguos a 10 positivos cada 100 pruebas. Mejorar la detección por rRT-PCR implica un aumento de al menos 20% en el costo de los reactivos, por lo que se necesitan recursos adicionales.

ABSTRACT Emerging respiratory viral infections like the severe coronavirus disease (CoVID 19) caused by novel coronavirus 2 (SARS-CoV-2) require quality results for science-based responses. The reverse transcriptase polymerase chain reaction (rRT-PCR) is considered the gold standard for detecting SARS-CoV-2 (particularly in the acute phase of infection). The aim of the present work was to analyze pitfalls during the search of viral genomes. False negative conclusions are result of sampling timing, performances of swabbing, storage, and thawing and heat-infectivity inactivation. Samples with low biologic material also lead to false negatives. Qualitative controls to detect the presence of human DNA are available in several kits but they were not calibrated for quantification of human cell loads. Moreover, negativity cannot be reported for samples with delayed signals for the internal control (due to deficiency in extraction and/or retro transcription and/or or to the presence of rRT-PCR inhibitors). The viral RNA that may have stick on gloves, on tubes, caps, etc. may produce false positives. The International Pharmacopoeias recommend for external contamination to test at least 10% of the samples. Couples of 10 negative contiguous to 10 positive controls randomly distributed should be therefore included in each series of 100 rRT-PCR tests. These improvements increase the cost of each determination (at least by 20% only for the reactants) and require additional resources.

Pulse oximetry screening for detection of congenital heart defects at 1646 m in Albuquerque, New Mexico.

AIM: To determine the false-positive rate of pulse oximetry screening at moderate altitude, presumed to be elevated compared with sea level values and assess change in false-positive rate with time. METHODS: We retrospectively analysed 3548 infants in the newborn nursery in Albuquerque, New Mexico, (elevation 5400 ft) from July 2012 to October 2013. Universal pulse oximetry screening guidelines were employed after 24 hours of life but before discharge. Newborn babies between 36 and 36 6/7 weeks of gestation, weighing >2 kg and babies >37 weeks weighing >1.7 kg were included in the study. Log-binomial regression was used to assess change in the probability of false positives over time. RESULTS: Of the 3548 patients analysed, there was one true positive with a posteriorly-malaligned ventricular septal defect and an interrupted aortic arch. Of the 93 false positives, the mean pre- and post-ductal saturations were lower, 92 and 90%, respectively. The false-positive rate before April 2013 was 3.5% and after April 2013, decreased to 1.5%. There was a significant decrease in false-positive rate (p = 0.003, slope coefficient = -0.082, standard error of coefficient = 0.023) with the relative risk of a false positive decreasing at 0.92 (95% CI 0.88-0.97) per month. CONCLUSION: This is the first study in Albuquerque, New Mexico, reporting a high false-positive rate of 1.5% at moderate altitude at the end of the study in comparison to the false-positive rate of 0.035% at sea level. Implementation of the nationally recommended universal pulse oximetry screening was associated with a high false-positive rate in the initial period, thought to be from the combination of both learning curve and altitude. After the initial decline, it remained steadily elevated above sea level, indicating the dominant effect of moderate altitude.

Elevación persistente de troponina I / Persistent elevation of troponin I

Resumen La troponina cardiaca es el marcador bioquímico más sensible y específico de daño/necrosis miocárdica, de ahí que desempeñe un papel crucial en el diagnóstico del síndrome coronario agudo. Sin embargo, en ocasiones, como en el caso clínico que se describirá, la elevación anormal de troponina no siempre obedece a un síndrome coronario agudo trombótico, sino a causa cardiaca sin enfermedad coronaria significativa, causa extracardiaca o alteración analítica (verdaderos falsos positivos). El interés de este caso radica en que siempre debería tenerse en mente la posibilidad de que se produzca un falso positivo de troponina por causa analítica, en especial en situaciones clínicas sin una razón obvia de daño miocárdico y cuando no sea evidente la confirmación de daño miocárdico mediante pruebas complementarias.

Abstract Cardiac troponin is the most sensitive and specific biochemical marker for myocardial damage / necrosis, and thus has a crucial role in the diagnosis of acute coronary syndrome. However, occasionally, as in the clinical case that will be described, the abnormal elevation of troponin does not always obey that of an acute coronary syndrome, but also to a cardiac cause with no significant coronary disease, extra-cardiac cause, or analytical change (true false positives). The interest in this case lies in that it should always be borne in mind that a false positive troponin can be produced due to an analytical cause. This can be the case in clinical situations with no obvious reason for myocardial damage and when the confirmation of myocardial damage may not be evident using complementary tests.

Zero inflated count regression for one year prediction of bovine trichomonosis in a compulsory control plan in La Pampa, Argentine.

Data from 533 farms with bovine trichomonosis were investigated through hurdle and zero inflated models to quantify the burden of recurrent bovine trichomonosis. The probability of having a positive result in the following year for those farms with a previous positive test was 10.7%. Keeping or buying infected animals increased the odds of having positive results by 2.8 (95% CI = 1.41-5.56). The number first cases significantly decreased the chances of being no-at-risk (OR = 0.64; 95% CI = 0.47-0.89) and the chances of being positive in the following season (OR = 1.09; 95% CI = 1.01-1.18). The number of animals tested significantly increased the chances of being positive in the next season (OR = 1.02; 95% CI = 1.01-1.03). Both the number of positives and the number of animals tested suggest a significant proportion of new cases detected were false positives. These epidemiologic indicators are likely important determinants in the selection of farms requiring more intensive control measures and farms where testing results should be confirmed.

Extrapleural solitary fibrous tumor evidenced by 68Ga-prostate-specific membrane antigen positron emission tomography/computed tomography study in the staging of a high-risk prostate cancer patient.

Positron emission tomography/computed tomography (PET/CT) using 68Ga-labeled prostate-specific membrane antigen (68Ga-PSMA) became an important tool in the prostate cancer (PC) diagnosis. Despite its high sensitivity and specificity, this method may produce false-positive findings, as indicated by previous studies. This case report aims to warn nuclear medicine physicians, oncologists, and urologists about the possibility of false-positive findings using this imaging modality, especially in patients who have already been diagnosed with other malignancies. A 69-year-old man, previously treated for an extrapleural solitary fibrous tumor (ESFT), underwent staging tests after a new diagnosis of high-risk PC. 68Ga-PSMA PET/CT imaging revealed an abnormal uptake in the prostate and in the right humerus. A biopsy was performed, and the pathology showed a lesion consisting of an ESFT metastasis. Diagnostic issues related to 68Ga-PSMA PET/CT imaging should be disseminated to help physicians make appropriate treatment choices for each patient and avoid unnecessary procedures.