Positive Predictive Value of ICD-10-CM Codes for Myocarditis in Claims Data: A Multi-Institutional Study in Taiwan.

Purpose: The validity of the diagnosis codes to identify myocarditis cases in healthcare databases research remains unclear, and this study aimed to determine the coding accuracy of myocarditis in Taiwan. Methods: We conducted a cross-sectional study based on Taiwan's largest multi-institutional healthcare system to identify inpatients newly diagnosed with ICD-10-CM myocarditis codes at discharge between January 1st, 2017 and March 31st, 2022. We ascertained the myocarditis diagnosis by a gold standard biopsy or by review of electronic medical records, and the positive predictive values (PPV) with 95% confidence intervals (CI) of the ICD-10-CM codes for myocarditis were determined. Results: We included a total of 498 inpatients (mean age: 33.8 years old; female: 38.8%) with new myocarditis diagnosis at discharge. Codes I409 (30.1%) and I514 (45.4%) constituted the majority of myocarditis diagnostic codes in any coding position, and the overall PPV of the myocarditis codes was 73.5% (95% CI: 69.6-77.4%). However, the highest PPV (96.6%) for myocarditis diagnosis was noted with code I409 as the primary diagnosis. We found 132 inpatients (26.5%) who were false-positive myocarditis cases, identified by the ICD-10-CM codes, and potential reasons for misclassification included other inflammation diseases (n=35, 26.5%), pre-existing heart failure (n= 25, 18.9%) and acute myocardial infarction (n=16, 12.1%). Conclusion: The PPV of ICD-10-CM codes for myocarditis in Taiwan was acceptable, but some other inflammation diseases and pre-existing heart diseases may be falsely coded as myocarditis. Our results may serve future secondary database studies as a fundamental reference on the validity of myocarditis diagnosis codes.

Comparison of clinician diagnosis of COVID-19 with real time polymerase chain reaction in an adult-representative population in Sweden.

BACKGROUND: Due to the high transmissibility of SARS-CoV-2, accurate diagnosis is essential for effective infection control, but the gold standard, real-time reverse transcriptase-polymerase chain reaction (RT-PCR), is costly, slow, and test capacity has at times been insufficient. We compared the accuracy of clinician diagnosis of COVID-19 against RT-PCR in a general adult population. METHODS: COVID-19 diagnosis data by 30th September 2021 for participants in an ongoing population-based cohort study of adults in Western Sweden were retrieved from registers, based on positive RT-PCR and clinician diagnosis using recommended ICD-10 codes. We calculated accuracy measures of clinician diagnosis using RT-PCR as reference for all subjects and stratified by age, gender, BMI, and comorbidity collected pre-COVID-19. RESULTS: Of 42,621 subjects, 3,936 (9.2%) and 5705 (13.4%) had had COVID-19 identified by RT-PCR and clinician diagnosis, respectively. Sensitivity and specificity of clinician diagnosis against RT-PCR were 78% (95%CI 77-80%) and 93% (95%CI 93-93%), respectively. Positive predictive value (PPV) was 54% (95%CI 53-55%), while negative predictive value (NPV) was 98% (95%CI 98-98%) and Youden's index 71% (95%CI 70-72%). These estimates were similar between men and women, across age groups, BMI categories, and between patients with and without asthma. However, while specificity, NPV, and Youden's index were similar between patients with and without chronic obstructive pulmonary disease (COPD), sensitivity was slightly higher in patients with (84% [95%CI 74-90%]) than those without (78% [95%CI 77-79%]) COPD. CONCLUSIONS: The accuracy of clinician diagnosis for COVID-19 is adequate, regardless of gender, age, BMI, and asthma, and thus can be used for screening purposes to supplement RT-PCR.

SARS-CoV-2 nucleic acid positive rate among close contacts of the patients infected with novel Coronavirus in China: a meta-analysis

The aim this meta-analaysis was to understand the current status of nucleic acid positivity rate of severe acute respiratory syndrome coronavirus (SARS-CoV-2) in close contacts of novel coronavirus-infected patients in China. The literature related to SARS-CoV-2 nucleic acid testing in close contacts of novel coronavirus-infected patients in China was searched in PubMed, EMbase, China Journal Full-text Data Base (CNKI), Wanfang Science and Technology Journal Full-text Database, and Veep Chinese Science and Technology Journal Full-text Database (VIP) from December 2019 to December 2020. 24 December 2019-2020. The quality of the literature was evaluated with reference to the revised American Agency for Healthcare Research and Quality (AHRQ) statement. StataSE15.0 software was used for meta-analysis, combined positive rates were calculated using the Freeman-Tukey double inverse sine conversion method, subgroup analysis was performed according to sex, age, infected person relationship, mode of infection and frequency of exposure, and sensitivity analysis and Egger's method was used to test for publication bias. Results A total of 11 publications were included, with a total sample size of 24 906 cases. The SARS-CoV-2 nucleic acid positivity rate in the close contact population of novel coronavirus-infected patients was 5.42% (95% CI: 3.57%-7.64%), and subgroup analysis showed that the positivity rate was 4.35% in males and 6.36% in females;the positivity rate was 5.88% in the 0-9 years group and 4.76% in the 10-59 years group. The positive rates were 5.88% for the 0-9 years group, 4.76% for the 10-59 years group and 8.73% for the =60 years group;13.42% for family members and 2.09% for others;11.44% for people living together, 9.90% for meals and 1.95% for other modes of infection;and 1.32%, 6.12% and 9.60% for occasional, normal and frequent contacts, respectively. The differences between the subgroups were statistically significant (?2 = 37.89 to 809.90, all P < 0.05). The sensitivity analysis suggested stable results and the Egger's test for publication bias was not statistically significant (t=0.93, P=0.376). Conclusion Close contacts of novel coronavirus-infected individuals in the Chinese region have a positive rate for SARS-CoV-2 nucleic acid.

Making Sense of Sensitivity: Using Candy and Anthropometric Data to Visually and Manipulatively Illustrate Sensitivity, Positive Predictive Value, and Related Terms.

The classic concepts of sensitivity and specificity are commonly taught by definition only, often with discipline-specific jargon and without any tangible relation to their use in the real world. Yet, the COVID pandemic and the spotlight on diagnostic screening tests have brought a need for science and health care students, health professionals, and the general public to have improved understanding of sensitivity and specificity and how they connect to further interpretive values. These understandings are critical for correct communications and explanations to those outside the sciences. Using simple candies or marbles as visuals, in conjunction with real-world scenarios, this activity was designed to help frame these concepts for students. Additionally, this activity provides practice with basic calculations and interpretations to reinforce how data can be used in determining testing values, surrogate testing, data cutoffs, and accuracy predictions. The activity is flexible and can easily be done in 1 to 2 h in a classroom setting, as a laboratory exercise, or as an outreach or online activity.

The importance of disease prevalence in clinical decision making: a real practice study on COVID-19 antigen test in Curacao.

The performance of a test can be suboptimal, but in appropriate setting such a test is still useful for clinical decision making. We investigated the role of Antigen Rapid Diagnostic Test (Ag-RDT) for clinical decision making in an Emergency Department (ED) in Curacao during peak of COVID-19 pandemic. Ag-RDT was performed in the naso- and oropharynx-swabs from patients with respiratory insufficiency presented to the ED. Ag-RDT was performed in 153 patients, of which 64 (41.8%) showed positive results. Comparing Ag-RDT results with molecular tests, its sensitivity was 68.8% (95% CI 57.4 to 78.7), and specificity of 94.6% (95% CI 84.9 to 98.9). The positive and negative predictive value were 95.1% (95% CI 86.5 to 98.3) and 66.3 (95% CI 58.6 to 73.3), respectively. All patients with Ag-RDT positive test were admitted to the cohorted COVD-19 department of the hospital. By using Ag-RDT, 35.9% of rapid PCR tests (that are more costly and laborious to perform) could be avoided at cost of 5.8% patients with false positive result. In conclusion, in real practice, disease prevalence is as important as test's performance for clinical decision making. The conclusion may also be applicable for other diagnostic tests than COVID-19 diagnostic.

Applicability of three nutritional screening tools in patients with liver cirrhosis under the Global Leadership Initiative on Malnutrition criteria. (Theme Issue: Diagnosis and treatment of liver failure in children.) [Chinese]

Objective: To investigate whether Royal Free Hospital Nutritional Prioritizing Tool (RFH-NPT) is more suitable than Nutritional Risk Screening 2002 (NRS-2002) in nutritional risk screening for patients with liver cirrhosis, as well as the applicability of subjective global assessment (SGA) in the nutritional assessment of patients with liver cirrhosis.

The Coronavirus Disease 2019 Spatial Care Path: Home, Community, and Emergency Diagnostic Portals.

This research uses mathematically derived visual logistics to interpret COVID-19 molecular and rapid antigen test (RAgT) performance, determine prevalence boundaries where risk exceeds expectations, and evaluate benefits of recursive testing along home, community, and emergency spatial care paths. Mathematica and open access software helped graph relationships, compare performance patterns, and perform recursive computations. Tiered sensitivity/specificity comprise: (T1) 90%/95%; (T2) 95%/97.5%; and (T3) 100%/≥99%, respectively. In emergency medicine, median RAgT performance peaks at 13.2% prevalence, then falls below T1, generating risky prevalence boundaries. RAgTs in pediatric ERs/EDs parallel this pattern with asymptomatic worse than symptomatic performance. In communities, RAgTs display large uncertainty with median prevalence boundary of 14.8% for 1/20 missed diagnoses, and at prevalence > 33.3-36.9% risk 10% false omissions for symptomatic subjects. Recursive testing improves home RAgT performance. Home molecular tests elevate performance above T1 but lack adequate validation. Widespread RAgT availability encourages self-testing. Asymptomatic RAgT and PCR-based saliva testing present the highest chance of missed diagnoses. Home testing twice, once just before mingling, and molecular-based self-testing, help avoid false omissions. Community and ER/ED RAgTs can identify contagiousness in low prevalence. Real-world trials of performance, cost-effectiveness, and public health impact could identify home molecular diagnostics as an optimal diagnostic portal.

Screening testing in health care: Getting it right.

BACKGROUND: There is a movement to engage oral health care professionals in administering tests to identify people at risk of developing contagious diseases and other medical conditions. The purpose of this overview was to provide clinicians with fundamental concepts to understand how to evaluate a screening test's capability to give a correct result and its implications for practice (health outcomes). TYPES OF STUDIES REVIEWED: The authors reviewed epidemiologic and statistical articles addressing the purpose of performing screening tests for medical conditions with a special emphasis on understanding and interpreting test results on the basis of specific test characteristics. RESULTS: Tests with different sensitivities and specificities will provide different probabilities of correctly classifying people with or without a disease of interest. By understanding how to interpret tests results and how to communicate the consequences (that is, impact on health outcomes) of positive and negative test results, oral health care professionals will be able to generate appropriate medical referrals and determine the need for further testing, as well as provide a public service. CONCLUSIONS AND PRACTICAL IMPLICATIONS: An understanding by oral health care professionals of how to interpret screening test results will benefit their patients substantially and, in the case of contagious diseases, the public at large.

Predictive values of time-dense SARS-CoV-2 wastewater analysis in university campus buildings.

Wastewater-based SARS-CoV-2 surveillance on college campuses has the ability to detect individual clinical COVID-19 cases at the building-level. High concordance of wastewater results and clinical cases has been observed when calculated over a time window of four days or longer and in settings with high incidence of infection. At Duke University, twice a week clinical surveillance of all resident undergraduates was carried out in the spring 2021 semester. We conducted simultaneous wastewater surveillance with daily frequency on selected residence halls to assess wastewater as an early warning tool during times of low transmission with the hope of scaling down clinical test frequency. We evaluated the temporal relationship of the two time-dense data sets, wastewater and clinical, and sought a strategy to achieve the highest wastewater predictive values using the shortest time window to enable timely intervention. There were 11 days with clinical cases in the residence halls (80-120 occupants) under wastewater surveillance with 5 instances of a single clinical case and 3 instances of two clinical cases which also corresponded to a positive wastewater SARS-CoV-2 signal. While the majority (71%) of our wastewater samples were negative for SARS-CoV-2, 29% resulted in at least one positive PCR signal, some of which did not correlate with an identified clinical case. Using a criteria of two consecutive days of positive wastewater signals, we obtained a positive predictive value (PPV) of 75% and a negative predictive value of 87% using a short 2 day time window for agreement. A conventional concordance over a much longer 4 day time window resulted in PPV of only 60%. Our data indicated that daily wastewater collection and using a criteria of two consecutive days of positive wastewater signals was the most predictive approach to timely early warning of COVID-19 cases at the building level.

Validity of ICD-10 codes for COVID-19 patients with hospital admissions or ED visits in Canada: a retrospective cohort study.

OBJECTIVE: To evaluate the validity of COVID-19 International Classification of Diseases, 10th Revision (ICD-10) codes and their combinations. DESIGN: Retrospective cohort study. SETTING: Acute care hospitals and emergency departments (EDs) in Alberta, Canada. PARTICIPANTS: Patients who were admitted to hospital or presented to an ED in Alberta, as captured by local administrative databases between 1 March 2020 and 28 February 2021, who had a positive COVID-19 test and/or a COVID-19-related ICD-10 code. MAIN OUTCOME MEASURES: The sensitivity, positive predictive value (PPV) and 95% CIs for ICD-10 codes were computed. Stratified analysis on age group, sex, symptomatic status, mechanical ventilation, hospital type, patient intensive care unit (ICU) admission, discharge status and season of pandemic were conducted. RESULTS: Two overlapping subsets of the study population were considered: those who had a positive COVID-19 test (cohort A, for estimating sensitivity) and those who had a COVID-19-related ICD-10 code (cohort B, for estimating PPV). Cohort A included 17 979 ED patients and 6477 inpatients while cohort B included 33 675 ED patients and 18 746 inpatients. Of inpatients, 9.5% in cohort A and 8.1% in cohort B received mechanical ventilation. Over 13% of inpatients were admitted to ICU. The length of hospital stay was 6 days (IQR: 3-14) for cohort A and 8 days (IQR: 3-19) for cohort B. In-hospital mortality was 15.9% and 38.8% for cohort A and B, respectively. The sensitivity for ICD-10 code U07.1 (COVID-19, virus identified) was 82.5% (81.8%-83.2%) with a PPV of 93.1% (92.6%-93.6%). The combination of U07.1 and U07.3 (multisystem inflammatory syndrome associated with COVID-19) had a sensitivity of 82.5% (81.9%-83.2%) and PPV of 92.9% (92.4%-93.4%). CONCLUSIONS: In Alberta, ICD-10 COVID-19 codes (U07.1 and U07.3) were coded well with high validity. This indicates administrative data can be used for COVID-19 research and pandemic management purposes.

Multicenter Postimplementation Assessment of the Positive Predictive Value of SARS-CoV-2 Antigen-Based Point-of-Care Tests Used for Screening of Asymptomatic Continuing Care Staff.

Frequent screening of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) among asymptomatic populations using antigen-based point-of-care tests (APOCTs) is occurring globally with limited clinical performance data. The positive predictive value (PPV) of two APOCTs used in the asymptomatic screening of SARS-CoV-2 among health care workers (HCWs) at continuing care (CC) sites across AB, Canada, was evaluated. Between 22 February and 2 May 2021, CC sites implemented SARS-CoV-2 voluntary screening of their asymptomatic HCWs. On-site testing with Abbott Panbio or BD Veritor occurred on a weekly or twice-weekly basis. Positive APOCTs were confirmed with a real-time reverse transcriptase PCR (rRT-PCR) reference method. A total of 71,847 APOCTs (17,689 Veritor and 54,158 Panbio) were performed among 369 CC sites. Eighty-seven (0.12%) APOCTs were positive, of which 39 (0.05%) were confirmed as true positives using rRT-PCR. Use of the Veritor and Panbio resulted in 76.6% and 30.0% false-positive detection, respectively (P < 0.001). This corresponded to PPVs of 23.4 and 70.0% for the Veritor and Panbio, respectively. Frequent screening of SARS-CoV-2 among asymptomatic HCWs in CC, using APOCTs, resulted in a very low detection rate and a high rate of detection of false positives. Careful assessment of the risks versus benefits of APOCT programs and the prevalence of infection in this population needs to be thoroughly considered before implementation.

Implications of Test Characteristics and Population Seroprevalence on "Immune Passport" Strategies.

Various forms of "immune passports" or "antibody certificates" are being considered in conversations around reopening economies after periods of social distancing. A critique of such programs focuses on the uncertainty around whether seropositivity means immunity from repeat infection. However, an additional important consideration is that the low positive predictive value of serological tests in the setting of low population seroprevalence and imperfect test specificity will lead to many false-positive passport holders. Here, we pose a simple question: how many false-positive passports could be issued while maintaining herd immunity in the workforce? Answering this question leads to a simple mathematical formula for the minimum requirements of serological tests for a passport program, which depend on the population prevalence and the value of the basic reproductive number, R0. Our work replaces speculation in the press with rigorous analysis, and will need to be considered in policy decisions that are based on individual and population serology results.

ICD-10 anaphylaxis algorithm and the estimate of vaccine-attributable anaphylaxis incidence in Medicare.

BACKGROUND: Anaphylaxis is a rare, serious allergic reaction. Its identification in large healthcare databases can help better characterize this risk. OBJECTIVE: To create an ICD-10 anaphylaxis algorithm, estimate its positive predictive values (PPVs) in a post-vaccination risk window, and estimate vaccination-attributable anaphylaxis rates in the Medicare Fee For Service (FFS) population. METHODS: An anaphylaxis algorithm with core and extended portions was constructed analyzing ICD-10 anaphylaxis claims data in Medicare FFS from 2015 to 2017. Cases of post-vaccination anaphylaxis among Medicare FFS beneficiaries were then identified from October 1, 2015 to February 28, 2019 utilizing vaccine relevant anaphylaxis ICD-10 codes. Information from medical records was used to determine true anaphylaxis cases based on the Brighton Collaboration's anaphylaxis case definition. PPVs were estimated for incident anaphylaxis and the subset of vaccine-attributable anaphylaxis within a 2-day post-vaccination risk window. Vaccine-attributable anaphylaxis rates in Medicare FFS were also estimated. RESULTS: The study recorded 66,572,128 vaccinations among 21,685,119 unique Medicare FFS beneficiaries. The algorithm identified a total of 190 suspected anaphylaxis cases within the 2-day post-vaccination window; of these 117 (62%) satisfied the core algorithm, and 73 (38%) additional cases satisfied the extended algorithm. The core algorithm's PPV was 66% (95% CI [56%, 76%]) for identifying incident anaphylaxis and 44% (95% CI [34%, 56%]) for vaccine-attributable anaphylaxis. The vaccine-attributable anaphylaxis incidence rate after any vaccination was 0.88 per million doses (95% CI [0.67, 1.16]). CONCLUSION: The ICD-10 claims algorithm for anaphylaxis allows the assessment of anaphylaxis risk in real-world data. The algorithm revealed vaccine-attributable anaphylaxis is rare among vaccinated Medicare FFS beneficiaries.

The potential of SARS-CoV-2 antigen-detection tests in the screening of asymptomatic persons.

OBJECTIVES: The aim was to assess the performance of antigen-based rapid diagnostic tests (Ag-RDTs) for SARS CoV-2 when implemented for large-scale universal screening of asymptomatic individuals. METHODS: This study was a pragmatic implementation study for universal Ag-RDT-based screening at a tertiary care hospital in Germany where patients presenting for elective procedures and selected personnel without symptoms suggestive of SARS-CoV-2 were screened with an Ag-RDT since October 2020. Test performance was calculated on an individual patient level. RESULTS: In total, 49 542 RDTs were performed in 27 421 asymptomatic individuals over a duration of 5 and a half months. Out of 222 positive results, 196 underwent in-house confirmatory testing with PCR, out of which 170 were confirmed positive, indicating a positive predictive value of 86.7% (95% CI 81.2-91.1%). Negative Ag-RDTs were not routinely tested with PCR, but a total of 94 cases of false negative Ag-RDTs were detected due to PCR tests being performed within the following 5 days with a median cycle threshold value of 33 (IQR 29-35). DISCUSSION: This study provides evidence that Ag-RDTs can have a high diagnostic yield for transmission relevant infections with limited false positives when utilized at the point of care on asymptomatic patients and thus can be a suitable public health test for universal screening.

Comparison of SARS-CoV-2 Detection by Rapid Antigen and by Three Commercial RT-qPCR Tests: A Study from Martin University Hospital in Slovakia.

The global pandemic of coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is having a tremendous impact on the global economy, health care systems and the lives of almost all people in the world. The Central European country of Slovakia reached one of the highest daily mortality rates per 100,000 inhabitants in the first 3 months of 2021, despite implementing strong prophylactic measures, lockdowns and repeated nationwide antigen testing. The present study reports a comparison of the performance of the Standard Q COVID-19 antigen test (SD Biosensor) with three commercial RT-qPCR kits (vDetect COVID-19-MultiplexDX, gb SARS-CoV-2 Multiplex-GENERI BIOTECH Ltd. and Genvinset COVID-19 [E]-BDR Diagnostics) in the detection of infected individuals among employees of the Martin University Hospital in Slovakia. Health care providers, such as doctors and nurses, are classified as "critical infrastructure", and there is no doubt about the huge impact that incorrect results could have on patients. Out of 1231 samples, 14 were evaluated as positive for SARS-CoV-2 antigen presence, and all of them were confirmed by RT-qPCR kit 1 and kit 2. As another 26 samples had a signal in the E gene, these 40 samples were re-isolated and subsequently re-analysed using the three kits, which detected the virus in 22, 23 and 12 cases, respectively. The results point to a divergence not only between antigen and RT-qPCR tests, but also within the "gold standard" RT-qPCR testing. Performance analysis of the diagnostic antigen test showed the positive predictive value (PPV) to be 100% and negative predictive value (NPV) to be 98.10%, indicating that 1.90% of individuals with a negative result were, in fact, positive. If these data are extrapolated to the national level, where the mean daily number of antigen tests was 250,000 in April 2021, it points to over 4700 people per day being misinterpreted and posing a risk of virus shedding. While mean Ct values of the samples that were both antigen and RT-qPCR positive were about 20 (kit 1: 20.47 and 20.16 for Sarbeco E and RdRP, kit 2: 19.37 and 19.99 for Sarbeco E and RdRP and kit 3: 17.47 for ORF1b/RdRP), mean Ct values of the samples that were antigen-negative but RT-qPCR-positive were about 30 (kit 1: 30.67 and 30.00 for Sarbeco E and RdRP, kit 2: 29.86 and 31.01 for Sarbeco E and RdRP and kit 3: 27.47 for ORF1b/RdRP). It confirms the advantage of antigen test in detecting the most infectious individuals with a higher viral load. However, the reporting of Ct values is still a matter of ongoing debates and should not be conducted without normalisation to standardised controls of known concentration.

Eleven routine clinical features predict COVID-19 severity uncovered by machine learning of longitudinal measurements.

Severity prediction of COVID-19 remains one of the major clinical challenges for the ongoing pandemic. Here, we have recruited a 144 COVID-19 patient cohort, resulting in a data matrix containing 3,065 readings for 124 types of measurements over 52 days. A machine learning model was established to predict the disease progression based on the cohort consisting of training, validation, and internal test sets. A panel of eleven routine clinical factors constructed a classifier for COVID-19 severity prediction, achieving accuracy of over 98% in the discovery set. Validation of the model in an independent cohort containing 25 patients achieved accuracy of 80%. The overall sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were 0.70, 0.99, 0.93, and 0.93, respectively. Our model captured predictive dynamics of lactate dehydrogenase (LDH) and creatine kinase (CK) while their levels were in the normal range. This model is accessible at https://www.guomics.com/covidAI/ for research purpose.

Positive Predictive Value of ICD-10 Diagnosis Codes for COVID-19.

PURPOSE: To examine the positive predictive value (PPV) of International Classification version 10 (ICD-10) diagnosis codes for Coronavirus disease 2019 (COVID-19). PATIENTS AND METHODS: Medical record review of all patients assigned a diagnosis code of COVID-19 (DB342A or DB972A) at six Danish departments of infectious diseases from February 27 through May 4, 2020. Confirmed COVID-19 diagnosis was defined as either: 1) definite, a positive polymerase chain reaction (PCR) for severe acute respiratory syndrome Coronavirus 2 (SARS-CoV-2) on a respiratory sample combined with symptoms suggestive of COVID-19: 2) probable, clinical presentation of COVID-19 without detection of SARS-CoV-2 and no alternative diagnoses considered more likely; or 3) possible, clinical presentation of COVID-19 without detection of SARS-CoV-2, and the patient was discharged or deceased before further investigations were carried out. We computed the PPV with 95% confidence intervals (CI) as the number of patients with confirmed (i.e., definite, probable, and possible) COVID-19 divided by the number of patients assigned a diagnosis code for COVID-19. RESULTS: The study included 710 patients with a median age of 61 years (interquartile range [IQR] 47-74) and 285/710 (40%) were female. COVID-19 was confirmed in 706/710 (99%) with 705/710 (99%) categorized as definite, 1/710 (0.1%) as probable, and 0 patients as possible COVID-19. The diagnosis was disproven in 4/710 (0.6%) patients who were hospitalized due to bacterial pneumonia (n = 2), influenza (n = 1), and urinary tract infection (n = 1). The overall PPV for COVID-19 was 99% (95% CI 99-100) and remained consistently high among all subgroups including sex, age groups, calendar period, and stratified by diagnosis code and department of infectious diseases (range 97-100%). CONCLUSION: The overall PPV of diagnosis codes for COVID-19 in Denmark was high and may be suitable for future registry-based prognosis studies of COVID-19.

[Reflections on the position of the Covid-19 antigenic test based on a discrepancy of result]. / Réflexions sur la place du test antigénique Covid-19 à partir d'un résultat discordant.

This case reports the result of a positive nasal swab for the SARS Antigen FIA Quidel, during the start of the realization of the antigen test, in a 26 years old asymptomatic nurse without any factors of risk who had been in contact with a COVID-19 patient three days ago. The result of the antigen test was not confirmed by the RT PCR test, which had been practiced twice. This leads us to discuss the Positive Predictive Value of the rapid tests for guidance, depending on the prevalence of the disease in the population on which they are used. This has many practical consequences for performing this test in an asymptomatic population or when used in mass screening. Care should be taken to use this test according to the correct indications.

Diagnostic accuracy of symptoms as a diagnostic tool for SARS-CoV 2 infection: a cross-sectional study in a cohort of 2,173 patients.

BACKGROUND: The SARS-CoV-2 pandemic continues to be a priority health problem; According to the World Health Organization data from October 13, 2020, 37,704,153 confirmed COVID-19 cases have been reported, including 1,079,029 deaths, since the outbreak. The identification of potential symptoms has been reported to be a useful tool for clinical decision-making in emergency departments to avoid overload and improve the quality of care. The aim of this study was to evaluate the performances of symptoms as a diagnostic tool for SARS -CoV-2 infection. METHODS: An observational, cross-sectional, prospective and analytical study was carried out, during the period of time from April 14 to July 21, 2020. Data (demographic variables, medical history, respiratory and non-respiratory symptoms) were collected by emergency physicians. The diagnosis of COVID-19 was made using SARS-CoV-2 RT-PCR. The diagnostic accuracy of these characteristics for COVID-19 was evaluated by calculating the positive and negative likelihood ratios. A Mantel-Haenszel and multivariate logistic regression analysis was performed to assess the association of symptoms with COVID-19. RESULTS: A prevalence of 53.72% of SARS-CoV-2 infection was observed. The symptom with the highest sensitivity was cough 71%, and a specificity of 52.68%. The symptomatological scale, constructed from 6 symptoms, obtained a sensitivity of 83.45% and a specificity of 32.86%, taking ≥2 symptoms as a cut-off point. The symptoms with the greatest association with SARS-CoV-2 were: anosmia odds ratio (OR) 3.2 (95% CI; 2.52-4.17), fever OR 2.98 (95% CI; 2.47-3.58), dyspnea OR 2.9 (95% CI; 2.39-3.51]) and cough OR 2.73 (95% CI: 2.27-3.28). CONCLUSION: The combination of ≥2 symptoms / signs (fever, cough, anosmia, dyspnea and oxygen saturation < 93%, and headache) results in a highly sensitivity model for a quick and accurate diagnosis of COVID-19, and should be used in the absence of ancillary diagnostic studies. Symptomatology, alone and in combination, may be an appropriate strategy to use in the emergency department to guide the behaviors to respond to the disease. TRIAL REGISTRATION: Institutional registration R-2020-3601-145, Federal Commission for the Protection against Sanitary Risks 17 CI-09-015-034, National Bioethics Commission: 09 CEI-023-2017082 .

Risk factors for a positive SARS-CoV-2 PCR in patients with common cold symptoms in a primary care setting - a retrospective analysis based on a joint documentation standard.

BACKGROUND: Combating the COVID-19 pandemic is a major challenge for health systems, citizens and policy makers worldwide. Early detection of affected patients within the large and heterogeneous group of patients with common cold symptoms is an important element of this effort, but often hindered by limited testing resources, false-negative test results and the lack of pathognomonic symptoms in COVID-19. Therefore, we aimed to identify anamnestic items with an increased/decreased odds ratio for a positive SARS-CoV-2 PCR (CovPCR) result in a primary care setting. METHODS: We performed a multi-center cross-sectional cohort study on predictive clinical characteristics for a positive CovPCR over a period of 4 weeks in primary care patients in Germany. RESULTS: In total, 374 patients in 14 primary care centers received CovPCR and were included in this analysis. The median age was 44.0 (IQR: 31.0-59.0) and a fraction of 10.7% (n = 40) tested positive for COVID-19. Patients who reported anosmia had a higher odds ratio (OR: 4.54; 95%-CI: 1.51-13.67) for a positive test result while patients with a sore throat had a lower OR (OR: 0.33; 95%-CI: 0.11-0.97). Furthermore, patients who had a first grade contact with an infected persons and showed symptoms themselves also had an increased OR for positive testing (OR: 5.16; 95% CI: 1.72-15.51). This correlation was also present when they themselves were still asymptomatic (OR: 12.55; 95% CI: 3.97-39.67). CONCLUSIONS: Several anamnestic criteria may be helpful to assess pre-test probability of COVID-19 in patients with common cold symptoms.