Confirmatory Result Research Articles

The diagnostic performance of the Visitect Advanced Disease point-of-care CD4 platform: a pragmatic mixed-methods multisite validation, costing, and qualitative analysis.

The Visitect CD4 Advanced Disease test (AccuBio, Alva, United Kingdom) is a rapid, semi-quantitative assay that estimates CD4 results above or below 200 cells/μL. We evaluated the performance of the Visitect CD4 assay in semi-urban laboratories in Uganda. We performed a pragmatic laboratory validation of the Visitect CD4 platform in four routine HIV clinics in Uganda, nested within a cluster randomized trial evaluating an enhanced package of screening and treatment for persons with advanced HIV disease (NCT05085171). As part of the clinical trial, samples processed on the Visitect CD4 platform were confirmed using another CD4 testing method. We compared the diagnostic performance of the Visitect CD4 platform against the confirmatory method by evaluating the sensitivity, specificity, positive and negative predictive values. Of 1495 venous blood samples that were processed both by the Visitect CD4 test and another confirmatory CD4 platform at clinics in Kampala, Uganda, specificity was 81% (95% CI, 79%-84%) and the positive predictive value was 69% (95% CI, 66%-73%). There were no samples for which the Visitect test was >200 cells/μL and the confirmatory test was ≤200 cells/μL, resulting in a sensitivity of 100%. Among Visitect CD4 tests that were read as <200 cells/μL with confirmatory results >200 cells/μL, the median confirmatory CD4 result was 397 (IQR, 281-590) cells/μL. Specificity varied by clinic ranging from 63% to 99%. Given variable specificity of the Visitect CD4 Advanced Disease platform, successful implementation will require consideration of clinic context and laboratory staffing.

8386 The Evolving Face of The Great Masquerader - Panhypopituitarism Associated with Neurosyphilis

Abstract Disclosure: M. Yabe: None. Z. Lin: None. F. Joseph: None. G. Philip: None. R. Silver: None. L. Callejas: None. J. Giunta: None. Untreated syphilis is on the rise in the United States. The CDC reported syphilis cases in newborns have increased 10-fold over a decade in November 2023, signifying the emergence of untreated infections. Pituitary involvement in syphilis is a very rare phenomenon, and endocrinological investigation is often overlooked. This will be the second reported case of neurosyphilis with pituitary involvement in a non-HIV infected patient. A 45-year-old female with no significant past medical history was admitted to the hospital with progressive neurological symptoms of intermittent left-side headache, hearing loss with tinnitus, and gait instability. Postcontrast MRI Brain revealed multifocal leptomeningeal enhancement involving supratentorial and infratentorial regions. Thickening of the enhanced pituitary infundibulum was also noted. Subsequent RPR titer showed 1:16 and lumbar puncture revealed CSF-VDRL titer 1:32, with pleocytosis 83 cells/uL, CSF-glucose 19 mg/dL, and CSF-protein 370 mg/dL. The patient completed Penicillin G 4 million/units intravenous every 4 hours for 14 days, with repeat MRI showing significant interval decrease in previously described extensive supratentorial and infratentorial leptomeningeal enhancement. However, there is no record of her sexual partner receiving treatment. The patient was readmitted one year later after a fall while displaying dysmetria. MRI Brain with contrast revealed a small subacute infarct along the right frontal corona radiata and pituitary gland measuring up to 1.2 cm in craniocaudal dimension compared to 0.4 cm on the prior exam. This prompted evaluation of pituitary hormones: FSH 0.8 IU/L, LH &amp;lt;0.3 IU/L, and ACTH 6.3 pg/mL, with normal serum growth hormone and prolactin levels. Further investigation revealed morning cortisol 2.5 ug/dL, thyrotropin &amp;lt; 0.2 uIU/mL, and free thyroxine 0.63 ng/dL. Radiological evidence is suspicious of inflammatory etiology of the pituitary gland. The patient was discharged with endocrinology follow-up and plan to perform a pituitary gland biopsy as an outpatient for confirmatory result. The association of neurosyphilis and hypophysitis leading to panhypopituitarism in a non-HIV infected patient was first reported in 2015. Since then, there remains limited research regarding their association due to rarity of pituitary involvement in neurosyphilis. With untreated syphilis on the rise and increased availability of MRI, clinicians should expect to encounter more cases of neurosyphilis with pituitary involvement in the future. Early detection of panhypopituitarism in those with positive CSF-VDRL titer could lead to better clinical outcomes. It is paramount that these cases are documented to emphasize pituitary involvement in neurosyphilis and encourage a low threshold to initiate endocrinological testing in the future. Presentation: 6/3/2024

Real-world performance of HIV low viral load values in diagnosing acute HIV infection in a tertiary care hospital in Beijing, China

BackgroundEarly diagnosis of HIV infection decreases the time from HIV diagnosis to viral suppression and reduces further HIV transmission. The Chinese Guidelines for the Diagnosis and Treatment of HIV/AIDS (2021 edition) state that an HIV RNA level > 5,000 copies/mL is the threshold for diagnosing HIV infection. The impact of low viral load values on HIV diagnosis needs to be investigated.MethodsThere were 3455 human immunodeficiency virus (HIV1 + 2) antibody results (immunoblotting method) and 65,129 HIV viral load values at Beijing Youan Hospital from 2019 to 2022. A total of 2434 patients had both antibody confirmatory results and viral load results. The confirmatory antibody results and HIV viral load results of 2434 patients were analyzed to investigate the impact of low viral load values on HIV diagnosis.ResultsOf the 2434 patients who had both confirmatory antibody results and viral load results, the viral load values of 140 patients (5.8%) had viral loads ranging from 40 copies/mL to 5,000 copies/mL before positive confirmatory antibody result, and of these 140 patients, the sample receipt time for the viral load tests of 96 (66.7%) individuals was 1 to 6 days earlier than the corresponding sample receipt time for the confirmatory antibody test. In addition, 34 patients (1.4%) had low viral loads ranging from 40 copies/mL to 1,000 copies/mL before positive confirmatory antibody result.ConclusionThis study revealed that there is a risk of missed diagnosis if a threshold of 5000 copies/mL is used for the diagnosis of HIV infection. These data provide valuable information for the early diagnosis of HIV infection, and our findings have potential benefits for decreasing HIV transmission.

Blood donation screening for hepatitis B virus core antibodies: The importance of confirmatory testing and initial implication for rare blood donor groups.

Exclusion of blood donors with hepatitis B virus (HBV) core antibodies (anti-HBc) prevents transfusion-transmitted HBV infection but can lead to significant donor loss. As isolated anti-HBc positivity does not always indicate true past HBV infection, we have investigated the effectiveness of confirmatory anti-HBc testing and the representation of rare blood groups in anti-HBc-positive donors. Three hundred ninety-seven HBV surface antigen-negative and anti-HBc initially reactive blood donor samples were tested by five different anti-HBc assays. Eighty percentage of samples reactive in Architect anti-HBc assay were positive by the Murex assay and anti-HBc neutralization. Eleven out of 397 samples showed discordant results in supplementary testing from the Murex confirmatory test result, and five remained undetermined following extensive serological testing. Thirty-eight percentage of anti-HBc-positive donors identified as minority ethnic groups compared with 11% representation in anti-HBc-negative donors (p < 0.0001); the frequency of the Ro blood group in anti-HBc-positive donors was 18 times higher in non-white ethnic groups. Using two anti-HBc assays effectively enabled the identification of HBV-exposed and potentially infectious donors, their deferral and potential clinical follow-up. However, the exclusion of confirmed anti-HBc-positive donors will still impact the supply of rare blood such as Ro.

Confirmatory digital subtraction angiography after clinical brain death/death by neurological criteria: impact on number of donors and organ transplants.

Demand for organs exceeds the number of transplants available, underscoring the need to optimize organ donation procedures. However, protocols for determining brain death (BD)/death by neurological criteria (DNC) vary considerably worldwide. In Denmark, digital subtraction angiography (DSA) is the only legally approved confirmatory test for diagnosing BD/DNC. We investigated the effect of the time delay caused by (repeat) confirmatory DSA on the number of organs donated by patients meeting clinical criteria for BD/DNC. We hypothesized that, first, patients investigated with ≥2 DSAs donate fewer organs than those investigated with a single DSA; second, radiological interpretation of DSA is subject to interrater variability; and third, residual intracranial circulation is inversely correlated with inotropic blood pressure support. All DSAs performed over a 7-year period as part of BD/DNC protocols at Rigshospitalet, Copenhagen University Hospital, Denmark, were included. Clinical data were extracted from electronic health records. DSAs were reinterpreted by an independent neurinterventionist blinded to the original radiological reports. We identified 130 DSAs in 100 eligible patients. Patients with ≥2 DSAs (n = 20) donated fewer organs (1.7 +/- 1.6 SD) than patients undergoing a single DSA (n = 80, 2.6 +/- 1.7 organs, p = 0.03), and they became less often donors (n = 12, 60%) than patients with just 1 DSA (n = 65, 81.3%; p = 0.04). Interrater agreement of radiological DSA interpretation was 88.5% (Cohen's kappa = 0.76). Patients with self-maintained blood pressure had more often residual intracranial circulation (n = 13/26, 50%) than patients requiring inotropic support (n = 14/74, 18.9%; OR = 0.23, 95% CI [0.09-0.61]; p = 0.002). In potential donors who fulfill clinical BD/DNC criteria, delays caused by repetition of confirmatory DSA result in lost donors and organ transplants. Self-maintained blood pressure at the time of clinical BD/DNC increases the odds for residual intracranial circulation, creating diagnostic uncertainty because radiological DSA interpretation is not uniform. We suggest that avoiding unnecessary repetition of confirmatory investigations like DSA may result in more organs donated.

480. Redefining the Epidemiologic Profile of Histoplasmosis from 2011 to 2021 in Central Ohio

Abstract Background Histoplasma is a common endemic mycosis in multiple Midwestern states. Most of the data defining epidemiologic risk are from 20th century outbreak investigations. A known exacerbating factor is immune suppression; but use of biologics, immunosuppressants (ISP), and chemotherapy has advanced since these investigations were conducted. This study sought to use clinical data from a tertiary care facility to address these gaps to define the evolving epidemiology of histoplasmosis in Ohio. Methods In a single-center retrospective cohort study, we identified adult patients with a histoplasmosis-specific diagnosis, a positive diagnostic test, and an itraconazole/amphotericin B prescription between 1/1/2012 and 10/1/2021. Prisoners were excluded. A random sample of 100 patients underwent in-depth chart review. Comorbidities, environmental risk factors, and ISP use data were collected. Cases were classified by the CDC 2017 Histoplasmosis case definition. “Confirmed” cases had culture growth, a confirmatory lab result, or histopathology plus signs and symptoms of disease, and “probable” cases had a non-confirmatory lab result plus signs and symptoms. Associations between variables were assessed using Fisher’s exact test, p &amp;lt; 0.05. Results Of 100 patients, 56 had confirmed and 22 had probable histoplasmosis (Table 1). Three had confirmed blastomycosis, 15 met definitions for both histoplasmosis and blastomycosis, and 4 met neither definition. These were excluded from analysis. No environmental exposure history was documented for 23 of 78 (29.4%) patients. Of those with documented history, 15 (27.1%) had recent renovation or construction exposure; 14 (25.4%) to soil, gardening, or outdoors; 12 (21.8%) to birds, bats, and farm animals; and 25 (45.4%) had no known exposure. There were 51 (65.4%) exposed to at least one dose of ISP in the year prior to diagnosis, including 41 (52.5%) to corticosteroids. Table 1Characteristics of patient cohort Conclusion In this cohort, more patients with confirmed or probable histoplasmosis were exposed to ISP than had a documented traditional environmental risk factor. This study shows reliance on traditional environmental exposure history might not accurately gauge risk. Further work is needed using ISP exposure to drive appropriate diagnostic testing. Disclosures All Authors: No reported disclosures.

Breast cancer screening pathways in Ghana: applying an exploratory single case study methodology with cross-case analysis

BackgroundBreast cancer is steadily increasing in Ghana, with the majority of Ghanaians only seeking care in the advanced stage of the disease. Furthermore, structured breast cancer control strategies are mostly non-existent. This study aimed to examine breast cancer and breast screening pathways in a tertiary healthcare facility within the Kumasi metropolis. MethodWe used a single exploratory case-study design to purposefully select one healthcare facility as a case with embedded sub-units of analysis (patients, first-degree relatives of patients, and clinicians) to address the study's aim. In-depth interview was used to generate evidence from 35 participants. Applying Miles and Huberman's thematic strategy, a cross-case analysis was conducted using Morse's analytical framework. ResultsFive (5) main themes emerged from the data: description of breast cancer, breast health education in Ghana, breast screening practices among women, the state of breast screening and barriers to breast screening uptake and lastly, the way forward. Malignancy of the breast was described as common, especially among young women who commonly present with advanced disease with poor prognostic outcomes. There were reports of limited breast cancer awareness and knowledge among women. Comparatively, urban educated women were noted to be relatively knowledgeable and more proactive about breast cancer than the less-privileged women in rural communities. Self and clinical-breast examination practices were reported as unusual habits for Ghanaian women. Several provider-related factors, lack of screening facilities, and attitude of women were highlighted as barriers to breast screening practices. Education among health professionals and interventions to promote opportunistic and organized breast screening were cited as the way forward for breast cancer control and early detection in Ghana. ConclusionThis is a confirmatory result of a stark burden of breast cancer in Ghana, inferring a need to address the deficiencies around breast cancer and early detection practices.

Using EHR data to identify coronavirus infections in hospitalized patients: Impact of case definitions on disease surveillance

PurposeTo evaluate the number, characteristics, and outcomes of patients identified hospitalized with coronavirus disease 2019 (COVID-19) using two different case definitions. ProceduresElectronic Health Record data were evaluated from patients hospitalized with COVID-19 through May 2020 at 52 health systems across the United States. Characteristics of inpatients with positive laboratory tests for SARS-CoV-2 were compared with those with clinical diagnosis of COVID-19 but without a confirmatory lab result. FindingsOf 14,371 inpatients with COVID-19, 6623 (46.1 %) had a positive laboratory result, and n = 7748 (52.9 %) had only a clinical diagnosis of COVID-19. Compared with clinically diagnosed cases, those with laboratory-confirmed COVID were similar in age and sex, but differed by race, ethnicity, and insurance status. Laboratory-confirmed cases were more likely to receive certain COVID-19 therapies including hydroxychloroquine, anti-IL6 agents and antivirals (p < 0.001). Those with laboratory–confirmed COVID-19 had lower rates of most complications such as myocardial infarction, but higher overall mortality (p < 0.001). ConclusionWe observed a two–fold difference in the number of patients hospitalized with COVID-19 depending on whether the case definition required laboratory confirmation. Variations in case definitions also led to differences in cohort characteristics, treatments, and outcomes.

Prediction of SARS-CoV-2 infection with a Symptoms-Based model to aid public health decision making in Latin America and other low and middle income settings

Symptoms-based models for predicting SARS-CoV-2 infection may improve clinical decision-making and be an alternative to resource allocation in under-resourced settings. In this study we aimed to test a model based on symptoms to predict a positive test result for SARS-CoV-2 infection during the COVID-19 pandemic using logistic regression and a machine-learning approach, in Bogotá, Colombia. Participants from the CoVIDA project were included. A logistic regression using the model was chosen based on biological plausibility and the Akaike Information criterion. Also, we performed an analysis using machine learning with random forest, support vector machine, and extreme gradient boosting. The study included 58,577 participants with a positivity rate of 5.7%. The logistic regression showed that anosmia (aOR = 7.76, 95% CI [6.19, 9.73]), fever (aOR = 4.29, 95% CI [3.07, 6.02]), headache (aOR = 3.29, 95% CI [1.78, 6.07]), dry cough (aOR = 2.96, 95% CI [2.44, 3.58]), and fatigue (aOR = 1.93, 95% CI [1.57, 2.93]) were independently associated with SARS-CoV-2 infection. Our final model had an area under the curve of 0.73. The symptoms-based model correctly identified over 85% of participants. This model can be used to prioritize resource allocation related to COVID-19 diagnosis, to decide on early isolation, and contact-tracing strategies in individuals with a high probability of infection before receiving a confirmatory test result. This strategy has public health and clinical decision-making significance in low- and middle-income settings like Latin America.

HIV oral self-screening test among HIV/STD/TB clinic attendees

Globally, several countries consider HIV self-test as an important element in the toolbox to end AIDS by 2030. Against this background, the present investigation was conducted to pilot test the performance of an indigenous HIV oral self-test (HIVOST) and explore its acceptability. The overall purpose was to examine if this kit could serve as a promising tool and merit future larger clinical evaluation. A concurrent mixed-method investigation was undertaken during March-October 2019. One hundred and thirty two consecutive HIV/sexually transmitted diseases/tuberculosis clinic attendees were invited for participation; of whom, 100 were enrolled, and among them, 40 provided consent for qualitative in-depth interviews. The HIVOST kit assessed for its performance served as the 'index test', which worked on the principle of lateral flow chromatography. The results of the HIVOST were interpreted independently by the study physicians and participants at 20 min. HIVOST kit performance was assessed against the HIV confirmatory blood test result based on the national algorithm (3 rapid test or 1 ELISA and 2 rapid test) serving as the 'reference'. Sensitivity, specificity, positive predictive value, negative predictive value and inter-rater agreement were estimated. The voices and concerns of the study participants were coded followed by identification of qualitative themes and ideas. The sensitivity and specificity of the index test at the end of 20 min as interpreted by the participants were 83.3 per cent [95% confidence interval (CI): 69.8 to 92.5] and 98 per cent (95% CI: 89.4 to 99.5), respectively. Study physicians and participants independently interpreted HIVOST results with substantial inter-rater agreement (kappa value 0.88; 95% CI: 0.78-0.97). All HIVOST test strips were valid. Majority of the participants preferred saliva over blood for HIV self-test. 'Comfort', 'confidentiality' and 'convenience' were the perceived advantages of HIVOST. Some of the participants wished the package inserts contained 'how-to-do instructions in local languages', 'expiry date (if any)' and 'contact helpline number'. A few of them highlighted the need for a confirmatory HIV result following oral self-test. Concerns of the participants revolved around potential self-harm following HIVOST-positive result and safe disposal of kits. Two major highlights of the present investigation are (i) high level of concordance in HIVOST results interpreted by participants and physicians, and (ii) encouraging level of acceptance of HIVOST. These findings and encouraging HIVOST performance statistics lend support towards large-scale clinical evaluation of this index test.

Acute Exacerbation of Rheumatoid Arthritis Misdiagnosed as COVID-19: A Case Report

BackgroundRheumatoid arthritis (RA) is a systemic inflammatory connective tissue disease that affects 1–2% of the population worldwide. Pulmonary manifestations including interstitial lung disease (ILD), airway disease, pleural and vascular disease can be seen in up to 30–40% of patients with RA, which are recognized as the second most frequent cause of death in RA patients. The simultaneous occurrence of COVID-19 in RA patients with or without ILD, and the similarities and differences between RA-related ILD and COVID-19 lung findings have been reported in the literature. However, there was no reported case on differentiation of clinical findings of a patient with RA exacerbation causing a new diagnosis of ILD during the pandemic conditions.Case PresentationHere, we presented a patient with RA who was misdiagnosed as COVID-19 twice due to non-specific respiratory symptoms and ground-glass opacities observed in high-resolution CT. The misdiagnosis led to a delayed diagnosis of ILD and prolonged pulmonary symptoms.DiscussionClinicians must critically review patients throughout the diagnostic workup by thinking other diseases besides COVID-19, particularly in the absence of a confirmatory result. The link between ILD or ILD exacerbation and COVID-19 remains to be determined. While research continues in the field, it is important to consider the importance of COVID-19 in cases of ILD exacerbation, and vice versa.ConclusionDistinguishing lung imaging findings of COVID-19 from ILD is a major concern. Even though the primary manifestation of COVID-19 consists of respiratory symptoms, clinicians should be vigilant for other common conditions having the same symptoms. Clinicians should carefully distinguish a differential diagnosis between COVID-19 and a flare of rheumatic disease.

1352. Changing Quality Indicators by Monitoring Veterans Using the Sexually TRansmitted Infection Key Evaluation (STRIKE) Dashboard

BackgroundDuring the COVID-19 pandemic, there have been multiple reports concerning patients falling out of healthcare. The National VA HIV and Hepatitis and Related Conditions (HHRC) has created the Sexually TRansmitted Infection Key Evaluation (STRIKE) Dashboard to help clinicians identify Veterans who need to complete co-testing for sexually transmitted infections (STIs) or human immunodeficiency virus (HIV) and allows providers to document if the Veteran was offered pre-exposure prophylaxis (PrEP).STRIKE Interface Screen MethodsA national VA Veteran dataset was generated from data within the Corporate Data Warehouse (CDW) that included all active PLWH. Positive HIV status is evaluated based on positive antibody test and positive confirmatory result or positive viral load lab result. Negative HIV status is evaluated based on a negative antibody test in the past year. Of the 140 sites, 39 participated but only 9 were active throughout the period of October 1, 2020 to March 31, 2021. Active and nonactive participating sites had metrics assessed across the study period at 3 time points: October 1, 2020, January 1, 2021 and April 1, 2021. Sites with at least 48 visits to report across the 6-month QI period were considered active.Patient level data for review Additional patient level data for review ResultsMultiple sites had scarcity of supplies due to the national shortage of CT/NG Test Kits during COVID-19. To improve access to CT/NG testing, the dashboard suppress the list of Veterans with + syphlis who were not co-tested for CT/NG. Co-testing improved from 60.2% to 77.2% in active sites and from 61.9% to 68.7% for nonactive across the study period. Percent of Veterans with completed HIV testing on or after STI diagnosis in active sites had an upward trend of 2.1% compared to the nonactive which increased 0.6%. Likewise, new diagnosis of STI for those on PrEP increased 2.6% in active and 0.5% increase in nonactive. On average, active sites increased percent of high risk veterans with active PrEP prescriptions by 2%, compared with nonactive that only increased 1%.STRIKE Co Testing and HIV Screen performed This graph shows average of Syphilis Co Testing and HIV screen performed by active and nonactive sites as measured at three different time point.Number of Veterans on PrEP with STIs This graph shows the average percent of veterans on PrEP with STIs between active versus nonactive sites as measured at three time pointsActive PrEP Prescriptions Across All Sites This graph shows average percent of active PrEP prescriptions for high risk patients between active versus nonactive sites as measured at three time pointsConclusionThe STRIKE Dashboard efficiently flags Veterans with STI diagnosis who need completion of STI co-testing, including HIV testing and PrEP offer. Active participating facilities who used the STRIKE Dashboard improved STI Co-testing and PrEP prescription in a short 6 month period even during COVID-19. Disclosures All Authors: No reported disclosures

Management of the Index COVID -19 Obstetric Patient at the University of Benin Teaching Hospital

Introduction: The novel coronavirus (COVID-19) was first identified in Wuhan City, Hubei province of China, November 2019. As at September 2020, over 28 million infections have been identified with almost a million deaths worldwide causing an alarming pandemic. Clinical presentations in pregnant patients with COVID-19 could be atypical with normal temperature (56%) and leukocytosis. This is further masked by the features of pregnancy.&#x0D; We present the management of a COVID-19 parturient in our obstetric unit.&#x0D; Case Report: A 32 year old unbooked G₃P₁⁺1 lady at 32 weeks who presented via referral from a private facility with a history of elevated blood pressure and ++ of protein in urine. Also, complaints of cough and difficulty with breathing. On examination she was noted to be anxious, afebrile, not pale, anicteric, acyanosed, not dehydrated. Had bilateral pedal oedema. Tachypnic with a respiratory rate of 28 cycles per min with basal crepitations. Pulse rate was 96bpm full and regular. Blood pressure was 180/100 mmHg. Heart sounds S₁S₂only.An impression of Chronic hypertension with superimposed pre-eclampsia at 32 wks GA in a primipara with one previous CS with pulmonary edema. Keep in view COVID-19.&#x0D; She was managed with oxygen, antihypertensives, steroids, while observing strict infection control protocol. She had an emergency caesarean section under subarachnoid block and was delivered of a live female neonate. A confirmatory positive result for covid-19 was obtained 24hrs later. Neonate was however negative. None of the staff became positive also.&#x0D; Conclusion: The management of suspected cases of COVID-19 infection should be same as cases already confirmed. As the epidemic persists, numbers will continue to rise andhence our index of suspicion should be heightened. Pregnant women will also present with symptoms masked by the features of a sick parturient. Full complement of PPE must be worn by all staff attending to both confirmed and suspicious cases of COVID-19 infection and strict adherence to stated protocols must be observed.

Evaluation of the INDICAID COVID-19 Rapid Antigen Test in Symptomatic Populations and Asymptomatic Community Testing.

ABSTRACTAs the COVID-19 pandemic progresses, there is an increasing need for rapid, accessible assays for SARS-CoV-2 detection. We present a clinical evaluation and real-world implementation of the INDICAID COVID-19 rapid antigen test (INDICAID rapid test). A multisite clinical evaluation of the INDICAID rapid test using prospectively collected nasal (bilateral anterior) swab samples from symptomatic subjects was performed. The INDICAID rapid test demonstrated a positive percent agreement (PPA) and negative percent agreement (NPA) of 85.3% (95% confidence interval [95% CI], 75.6% to 91.6%) and 94.9% (95% CI, 91.6% to 96.9%), respectively, compared to laboratory-based reverse transcriptase PCR (RT-PCR) using nasal specimens. The INDICAID rapid test was then implemented at COVID-19 outbreak screening centers in Hong Kong as part of a testing algorithm (termed “dual-track”) to screen asymptomatic individuals for prioritization for confirmatory RT-PCR testing. In one approach, preliminary positive INDICAID rapid test results triggered expedited processing for laboratory-based RT-PCR, reducing the average time to confirmatory result from 10.85 h to 7.0 h. In a second approach, preliminary positive results triggered subsequent testing with an onsite rapid RT-PCR, reducing the average time to confirmatory result to 0.84 h. In 22,994 asymptomatic patients, the INDICAID rapid test demonstrated a PPA of 84.2% (95% CI, 69.6% to 92.6%) and an NPA of 99.9% (95% CI, 99.9% to 100%) compared to laboratory-based RT-PCR using combined nasal/oropharyngeal specimens. The INDICAID rapid test has excellent performance compared to laboratory-based RT-PCR testing and, when used in tandem with RT-PCR, reduces the time to confirmatory positive result.IMPORTANCE Laboratory-based RT-PCR, the current gold standard for COVID-19 testing, can require a turnaround time of 24 to 48 h from sample collection to result. The delayed time to result limits the effectiveness of centralized RT-PCR testing to reduce transmission and stem potential outbreaks. To address this, we conducted a thorough evaluation of the INDICAID COVID-19 rapid antigen test, a 20-minute rapid antigen test, in both symptomatic and asymptomatic populations. The INDICAID rapid test demonstrated high sensitivity and specificity with RT-PCR as the comparator method. A dual-track testing algorithm was also evaluated utilizing the INDICAID rapid test to screen for preliminary positive patients, whose samples were then prioritized for RT-PCR testing. The dual-track method demonstrated significant improvements in expediting the reporting of positive RT-PCR test results compared to standard RT-PCR testing without prioritization, offering an improved strategy for community testing and controlling SARS-CoV-2 outbreaks.

Hepatitis C virus screening of high-risk patients in a community hospital emergency department: Retrospective review of patient characteristics and future implications.

BackgroundChronic hepatitis C virus infection (HCV) is a common infectious disease that affects more than 2.7 million people in the US. Because the emergency department (ED) can present an ideal opportunity to screen patients who may not otherwise get routine screening, we implemented a risk-based screening program for ED patients and established a system to facilitate linkage to care.Methods and findingsA risk-based screening algorithm for HCV was programmed to trigger an alert in Epic electronic medical record system. Patients identified between August 2018 and April 2020 in the ED were tested for HCV antibody reflex to HCV RNA. Patients with a positive screening test were contacted for the confirmatory test result and to establish medical care for HCV treatment. Patient characteristics including age, sex, self-awareness of HCV infection, history of previous HCV treatment, history of opioids use, history of tobacco use, and types of insurance were obtained.A total of 4,525 patients underwent a screening test, of whom 131 patients (2.90%) were HCV antibody positive and 43 patients (0.95%) were HCV RNA positive, indicating that only 33% of patients with positive screening test had chronic HCV infection. The rate of chronic infection was higher in males as compared to females (1.34% vs 0.60%, p = 0.01). Patients with history of opioid use or history of tobacco use were found to have a lower rate of spontaneous clearance than patients without each history (opioids: 48.6% vs 72.0%, p = 0.02; tobacco: 56.6% vs 80.5%, p = 0.01). Among 43 patients who were diagnosed with chronic hepatitis C, 26 were linked to a clinical setting that can address chronic HCV infection, with linkage to care rate of 60.5%. The most common barrier to this was inability to contact patients after discharge from the ED.ConclusionsA streamlined EMR system for HCV screening and subsequent linkage to care from the ED can be successfully implemented. A retrospective review suggests that male sex is related to chronic HCV infection, and history of opioid use or history of tobacco use is related to lower HCV spontaneous clearance.

Process parameter optimization to reduce cold metal defect in ferrous casting using Taguchi technique and regression analysis

This paper represents to select the optimized sand casting process parameters to reduce the cold metal defect in 100 mm flange, a ferrous casting. The experiments are conducted using the L27 orthogonal array of the Taguchi technique. The S/N ratio gives the best parameter combination to produce quality casting and the mathematical model is developed using regression analysis. The confirmatory test result shows that the cold metal casting rejection rate is reduced to 10% from 23%.

428. Very High Clinical Likelihood (VHCL) Of COVID-19 Infection: Peering Beyond A Negative Nasopharyngeal Swab

BackgroundDiagnosis of COVID-19 relies upon RT-PCR assays for SARS-CoV-2 from a nasopharyngeal swab (NPS). However, results depend upon duration of illness at the time of testing and operator performance. False negatives occur 10–30% of the time. In our center we formulated & applied a clinical prediction tool for diagnosis of COVID-19 infection. Patients who satisfied criteria were designated as having COVID-19 regardless of NPS results. Herein, we describe the set of patients who fulfilled full and strict clinical criteria (VHCL) (Table 1) and had at least 2 negative NPSs on hospital admission.Table 1: Clinical criteria for Very High Clinical Likelihood of COVID-19 Infection (VHCL COVID-19) MethodsA retrospective descriptive study was conducted from March 4th to April 11th, 2020. We evaluated patients with ≥ 2 consecutive negative NPS COVID-19 results admitted to our hospital. Of these, we identified patients fitting all 5 criteria for Very High Clinical Likelihood (VHCL) of COVID-19 infection (Table 1). We analyzed symptoms & lab data (including results of repeat NPS testing if performed) in those patients.Results1855 patients were diagnosed with COVID-19 in the study period. Of these, 23 had ≥ 2 negative COVID-19 NPS results but met criteria for VHCL (Table 2). Of these 23, 7 had a subsequent 3rd NPS that was positive-proving infection. Similar to other reports, patients had low lymphocytes and elevated procalcitonin, ferritin, C-reactive protein levels. And consistent with proven cases, our cohort presented after a median of 5 days of symptoms (Table 3).Table 2: Clinical and laboratory characteristics of VHCL COVID-19 patients [Rows Bolded include those patients who had a 3rd NPS swab that was positive]. Table 3: Demographic and Median Lab Data of VHCL COVID-19 patients ConclusionIt is critical to be mindful of the imperfection of laboratory testing & to integrate clinical criteria to diagnostic algorithms. This is especially true in the COVID-19 pandemic, which is marked by high morbidity & mortality. In our study, we demonstrated how a set of clinical parameters (which we termed VHCL) can aid in widening the net of patients diagnosed with COVID-19 despite negative laboratory tests. While 16 patients in our cohort did not have a confirmatory result, the strict criteria for VHCL & the close match of other study variables with those of proven cases supports the value of VHCL designation. Applying VHCL can optimize infection control, identify patients for emerging therapeutics & aid in contact tracing to reduce nosocomial & community transmission of COVID-19.Disclosures All Authors: No reported disclosures

CHEST IMAGING FOR EARLY DIAGNOSIS OF COVID-19 ON A PATIENT WITHOUT RESPIRATORY SYMPTOMS: A CASE REPORT

Background: The Coronavirus 2019 disease (COVID-19) is transmitted through droplet and aerosol from the respiratory tract of an infected person; and fomites from infected linen and surface. On August 1, 2020, in Yogyakarta, there were 741 confirmed positive cases of COVID-19, and it is still possible to increase. In the time of understanding COVID-19, there are many cases with atypical presentation, including gastrointestinal symptoms.&#x0D; Objective: To describe a COVID-19 case without respiratory symptoms and the role of radiology in detecting COVID-19.&#x0D; Case Description: A 55-year-old male patient came to the hospital complaining of nausea and loss of appetite. Based on the results of the physical examination, there was flatulence. Initial investigations revealed a non-reactive SARS CoV 2 IgG and IgM result. Further non-contrast MSCT Thorax showed infiltrates with bilateral sub-pleural posterolateral consolidation, particularly the left, showing typical pneumonia. Multiple blebs were also found, denoting bronchiectasis. Confirmatory RT-PCR result was positive for SARS CoV 2.&#x0D; Conclusion: COVID-19 usually presents with common respiratory symptoms. However, some patients also experience gastrointestinal symptoms that initially were not detected as COVID-19. In time of COVID-19 pandemic, persistent gastrointestinal symptoms in a high-risk patients warrant further chest imaging and RT-PCR of SARS CoV-2 to detect or exclude the possibility of COVID-19 diagnosis.

Evaluating agents’ trustworthiness within virtual societies in case of no direct experience

A great deal of effort has been made to introduce trust models to assess trustworthiness within virtual societies. The great majority of them makes extensive use of direct experience as the main source of information, considering recommendation/reputation and inferential processes just later, as a secondary mechanism to refine trust assessment. In this kind of networks, unfortunately, direct experience might not always represent the best solution to assess trustworthiness. In fact, their highly dynamic structure promotes an increase of the average number of interconnections among agents. This in turn negatively affects the degree of knowledge the agents possess about each specific individual, i.e. direct experience. To date, however, it has not been said much about how to face these situations.It is fundamental to find an effective approach for trust assessment even in lack of direct experience, which is the central focus of this research. By the means of a multi-agent social simulation, we consider the situation in which an agent can just access indirect knowledge for trust assessment, namely recommendations of specific individuals or whole categories of individuals. Then, we compare the efficiency of these two approaches in order to identify when it is more convenient to rely on the first or on the second one. As expected, our results confirm that the dynamic nature of these networks strongly affects the role of categories. We modeled this feature introducing the “turnover” in the simulations, whereby the higher is the turnover the more convenient it is relying on categories. Besides this confirmatory result, our simulations highlight the higher degree of robustness of categories in the presence of unreliable recommenders. Such a result is even more significant if there is no available information about how reliable the recommenders are.The results we obtained are in accordance with the current literature and can be of important interest for the development of this sector.

1296. Should HIV Disclosure at ED Based on Preliminary Results?

BackgroundIt is recommended that all adults presenting to Emergency Departments (ED) be offered opt out testing for HIV. There is evidence that detection of HIV infection, disclosure of infected status to the patient, and enrollment into HIV care are best accomplished during the ED visit. Any delay results in loss of patients. Among critical variables are capacities to conduct screening and confirmatory testing during the time the patient is a resident in the ED. We report on a facility where HIV screening is performed during ED patient dwell times but confirmatory results follow in ≥24h. The conundrum is whether patients found HIV positive by a screening test should be informed of the positive screening finding before confirmatory results are in hand.MethodsData obtained from a routine opt-out HIV screening program for the interval June 2017 to March 2019 conducted at the ED in Houston, Texas were evaluated. Patients between 18–65 years with Glasgow Score >9 were eligible for testing. HIV fourth-generation ADVIA Centaur™ Ag/Ab COMBO (Siemens) was used for screening. Positives screening tests were followed by Gennius™ HIV1/HIV2 confirmatory test.Results12,040 HIV fourth-generation tests were performed; 232 (1.9%) were positive; the specificity of the screening testing was 98.2%. Twenty-two (9.5%) of screening test positive individuals were found HIV false positive (Ag/Ab positive and Gennius negative). The population had a mean age of 43.8 years (21–64), was predominately female (63.6%) and white (40.9%). Further testing was completed for 14 of the 22 patients with false-positive screening tests. 13 had negative tests for HIV RNA and 1 had a second HIV Ag/Ab test with negative findings. 8 (36.3%) screening test false-positive patients could not be located after their departure from the ED.ConclusionIf patients were disclosed of their HIV-positive status because of the screening test result, approximately 10% of these individuals would have been incorrectly categorized generating significant personal and social disruption while waiting for the confirmatory result.Disclosures All authors: No reported disclosures.