scholarly journals Chlamydia trachomatis screening in resource-limited countries – Comparison of diagnostic accuracy of 3 different assays

2018 ◽  
Vol 12 (09) ◽  
pp. 733-740
Author(s):  
Jelena Zivadin Tosic-Pajic ◽  
Predrag Sazdanovic ◽  
Marija Sorak ◽  
Jelena Cukic ◽  
Aleksandra Arsovic ◽  
...  
Keyword(s):  
Chlamydia Trachomatis ◽  
Diagnostic Accuracy ◽  
Statistical Significance ◽  
Acute Infection ◽  
False Negative ◽  
Screening Tests ◽  
Rt Pcr ◽  
Serum Igg ◽  
Significant Difference ◽  
Youden’S Index

Introduction: Commercially available assays were evaluated in order to determine diagnostic accuracy of Chlamydia trachomatis specific tests for screening. Methods: The study included 225 sexually active men and women, who were tested for genital chlamydial infection in Institute of Public Health Kragujevac. Three screening tests were used: direct immunofluorescence (DIF) and rapid lateral immunochromatographic test (RT) for qualitative detection of chlamydial antigens and immunoenzyme (ELISA) test for detection of serum levels of anti-chlamydial IgA and IgG antibodies. Diagnostic efficiency of these tests were determined in relation to results obtained by RT-PCR method. Results: Statistical significance between the results obtained by RT-PCR as a gold standard and DIF, RT and ELISA were analyzed using chi-square (χ2) test. Statistical analysis showed a significant difference between RT-PCR and analyzed screening tests: DIF (χ2 = 303; p < 0.001), RT (χ2 = 4.19; p = 0.041), serum IgA (χ2 = 4.19; p = 0.041) and serum IgG (χ2 = 67; p < 0.001) which indicates poor agreement between these tests. Large numbers of false positive (FP) and false negative (FN) results were observed for all tested assays. According to Youden’s index, serum IgG and DIF testing demonstrated the most-balanced sensitivity-specificity rate. RT assay exhibits the highest expanded Youden’s index, as well as the best overall diagnostic accuracy. Conclusions: None of evaluated screening tests can be recommended as individual method for the diagnosis of acute infection. We suppose that RT-PCR is unlikely to be a cost-effective screening strategy within the Serbian health system.

scholarly journals Diagnostic Utility of Serum Ascites Lipid and Protein Gradients in Differentiation of Ascites

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Mukhyaprana Prabhu ◽  
Rahul Sai Gangula ◽  
Weena Stanley
Keyword(s):  
Ascitic Fluid ◽  
Clinical Laboratory ◽  
Statistical Significance ◽  
Hdl Cholesterol ◽  
Malignant Ascites ◽  
Screening Tests ◽  
Diagnostic Utility ◽  
Roc Curve Analysis ◽  
Significant Difference ◽  
Protein Gradients

Context. Ability of SAAG to differentiate malignant ascites from other aetiologies like tubercular peritonitis is a major problem. Alternate screening test is needed for differentiating ascites due to malignancy from those due to tubercular peritonitis. Aims. To study the diagnostic utility of serum ascites lipid gradients and serum ascites protein gradients in pathophysiological differentiation of ascites. Settings and Design. The present study is a prospective, descriptive, hospital-based, cross-sectional study. Methods and Material. The study was conducted on patients with ascites who were admitted to General Medicine Department, Kasturba Hospital, Manipal. The study included 60 patients with ascites of different etiologies (liver cirrhosis, tubercular peritonitis, and malignant ascites). All of them had undergone clinical, laboratory, and imaging investigations and were treated as per standard of care. All patients underwent abdominal paracentesis, and fluid samples were sent for analysis. Statistical Analysis Used. ANOVA, Kruskal-Wallis H test, and ROC curve analysis. Results. Among the gradients, only SAPG and SAAG had over all statistical significance (<0.005) among the groups, but no significance between malignancy and tubercular peritonitis had been observed. Similarly all the ascitic fluid parameters measured had an overall statistical significance (<0.005), but there was no significant difference observed between malignancy and tubercular peritonitis groups. However, ascitic fluid and serum HDL cholesterol had a statistical significance (<0.05) between malignancy and tubercular peritonitis. Conclusions. With a cut-off value of 4, SAPG is one of best screening tests in differentiation of cirrhotic with noncirrhotic ascites when compared with SAAG, whereas it is a poor parameter with high sensitivity and very low specificity in differentiation of malignant with nonmalignant ascites. Also the present study reveals HDL cholesterol levels in ascitic fluid to be a valuable marker with higher sensitivity and specificity in differentiation of malignancy and tuberculosis peritonitis (i.e., differentiation of low SAAG ascites).

Coagulation Markers Levels Measured during Acute Infection May Predict the Development of Long Term Cardio- and Cerebro-Vascular Events in Elderly.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 3989-3989
Author(s):  
Asher Winder ◽  
Tatiana Bruzgol ◽  
Inna Lichman ◽  
Amir Herman ◽  
Eyal Leibovitz ◽  
...  
Keyword(s):  
High Risk ◽  
Statistical Significance ◽  
Acute Infection ◽  
Coagulation System ◽  
Plasminogen Activator Inhibitor 1 ◽  
Vascular Events ◽  
Coronary Syndrome ◽  
Significant Difference ◽  
D Dimer

Abstract Introduction: The coagulation system plays a pivotal role in the creation and development of vascular clotting. It is activated during infection episodes, as can be measured by different markers like, d-dimer, plasminogen activator inhibitor-1 (PAI1) and fibrinogen. The goal of this study was to check whether high levels of d-dimer, fibrinogen or PAI1 during acute infection, as markers of the coagulation system, indicates higher risk for cerebro-cardiovascular disease or any cause mortality in elderly during 6 months after the infection episode. Methods: Coagulation markers, d-dimer, fibrinogen and PAI1 levels as well as other routine demographic and laboratory variables were recorded in elderly patients hospitalized due to infections. The variables were recorded at the time of admission, at discharge and at 6 months after discharge. End points of the study were Cerebro vascular events, acute coronary syndrome, other thromboembolic events and all cause mortality. Results: The study group consisted of 52 patients, 5 of them died during hospitalization, 4 died later from infectious complications and 6 had a cerebrovascular or cardiovascular (CCV) event. Lower fibrinogen levels were associated with development of CCV events. A statistically significant difference (p=0.048) was found between fibrinogen levels at time of discharge from the hospital among patients with CCV event (366±149 mg/dL) compared to the levels among patients without CCV event (511±139 mg/dL), though comparing fibrinogen levels at admission did not reach statistical significance (patients with CCV event −456±70 mg/dL, patients without CCV event −544±133 mg/dL, p=0.052). Furthermore, the ratio of d-dimer levels measured in admission to the levels at discharge was found to be significantly higher (p=0.029) in patients that eventually had CCV event (1.60±0.5) compared to patients who did not have CCV event (1.12±0.4). PAI-1, Platelets or other Blood variables were not significantly different between the groups. Based on these differences an algorithm was build to identify patients with infection in high risk for CCV event (figure). Patients with fibrinogen levels on admission below 530 mg/dL and d-dimer ratio above 1.54 were identified to be at high risk for CCV event. The algorithm yielded a sensitivity and specificity of 66% and 95%, respectively. The hazard ratio for these patients was found to be 16.8 (95% confidence interval: 3.06–92). Conclusions: In this study we found that lower levels of fibrinogen are associated with higher risk for developing a CCV event, while the opposite occurs for d-dimer ratio. An algorithm was developed for identification of high risk patients. Further research is needed to validate these results in order to identify a group of people that might benefit from long term antithrombotic agents in order to prevent cardio and cerebro-vascular events. Figure Figure

Usefulness of composite methionine–positron emission tomography/3.0-tesla magnetic resonance imaging to detect the localization and extent of early-stage Cushing adenoma

2010 ◽  
Vol 112 (4) ◽  
pp. 750-755 ◽  
Author(s):  
Hidetoshi Ikeda ◽  
Takehiko Abe ◽  
Kazuo Watanabe
Keyword(s):  
Mr Imaging ◽  
Diagnostic Accuracy ◽  
Fdg Pet ◽  
Early Stage ◽  
False Negative ◽  
Mr Images ◽  
Cushing Disease ◽  
Significant Difference ◽  
3.0 T ◽  
Met Pet

Object Fifty to eighty percent of Cushing disease is diagnosed by typical endocrine responses. Recently, the number of diagnoses of Cushing disease without typical Cushing syndrome has been increasing; therefore, improving ways to determine the localization of the adenoma and making an early diagnosis is important. This study was undertaken to determine the present diagnostic accuracy for Cushing microadenoma and to compare the differences in diagnostic accuracy between MR imaging and PET/MR imaging. Methods During the past 3 years the authors analyzed the diagnostic accuracy in a series of 35 patients with Cushing adenoma that was verified by surgical pituitary exploration. All 35 cases of Cushing disease, including 20 cases of “overt” and 15 cases of “preclinical” Cushing disease, were studied. Superconductive MR images (1.5 or 3.0 T) and composite images from FDG-PET or methionine (MET)–PET and 3.0-T MR imaging were compared with the localization of adenomas verified by surgery. Results The diagnostic accuracy of superconductive MR imaging for detecting the localization of Cushing microadenoma was only 40%. The causes of unsatisfactory results for superconductive MR imaging were false-negative results (10 cases), false-positive results (6 cases), and instances of double pituitary adenomas (3 cases). In contrast, the accuracy of microadenoma localization using MET-PET/3.0-T MR imaging was 100% and that of FDG-PET/3.0-T MR imaging was 73%. Moreover, the adenoma location was better delineated on MET-PET/MR images than on FDG-PET/MR images. There was no significant difference in maximum standard uptake value of adenomas evaluated by MET-PET between preclinical Cushing disease and overt Cushing disease. Conclusions Composite MET-PET/3.0-T MR imaging is useful for the improvement of the delineation of Cushing microadenoma and offers high-quality detectability for early-stage Cushing adenoma.

Natural History of Post-Allogeneic HSCT EBV-Reactivation: A Single Center Retrospective Survey.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3232-3232
Author(s):  
Helene M. Schoemans ◽  
Koen Theunissen ◽  
Marc Boogaerts ◽  
Johan Maertens
Keyword(s):  
Opportunistic Infections ◽  
Screening Tests ◽  
Rt Pcr ◽  
Post Transplantation ◽  
Hematopoietic Stem ◽  
Allogeneic Hsct ◽  
Ebv Reactivation ◽  
Number Of Patients ◽  
Significant Difference

Abstract Epstein Barr Virus (EBV) reactivation occurs in about 50% of the allogeneic hematopoietic stem cell transplantation (HSCT) population in the first year post-transplantation. About 1-7% of these patients run the risk of developing a post-transplant lymphoproliferative disorder (PTLD). Several authors have thus advocated systematic screening by EBV real time PCR (RT-PCR) to initiate pre-emptive treatment of reactivations using Rituximab (van Esser 2002). However, the positive predictive value of EBV RT-PCR is only of 40% (van Esser 2001), implying that this algorithm overtreats a number of patients. Methods: We have retrospectively analyzed 60 consecutive allogeneic HSCT patients transplanted in our center between 1/1/2004 and 31/3/2005. Four patients were excluded because of absence of EBV follow-up (n=2) or autologous reconstitution (n=2). EBV reactivation (EBV (+)) was defined by at least two consecutive episodes of EBV RT-PCR above 1000 copies/ml of whole blood. Any other result was considered as negative (EBV (−)). Results: 1175 EBV RT-PCR samples were collected over a median follow up of 215 days (range: 21–511). The population observed was essentially adults (median age 42 years, range: 1–65) with leukemia (29 leukemia, 11 lymphomas, 16 other diseases), mixed graft types (26 matched sibling donors, 26 matched unrelated donors, 4 haploidentical donors; 77% peripheral blood stem cells; 20% CD34+ selection) and mixed conditioning (52% non-myeloablative conditioning containing ATG, and 48% full conditioning). The EBV(+) and EBV(−) cohorts were similar for all characteristics analyzed. We observed a median of 18 EBV RT-PCR per patient (range: 4–105), with a median interval between two tests of 7 days (range: 3–45). There were 30 true reactivations, 2 intermittent reactivations (non consecutive EBV titer rises above threshold), 8 isolated reactivations and 16 patients with no reactivation episode. EBV RT-PCR was first performed at a median of 6 days post HSCT (range: 0–245), and reactivation was noted at a median of 44 days post HSCT (range: 6–375). There were no significant difference in PCR follow up (first day of screening, median test interval and length of biological follow up) except for the total number of screening tests per patient, which was higher in the EBV(+) group (p= 0.01). There was only one case of biopsy-proven PTLD in the EBV(+) cohort. No patient was administered Rituximab post- HSCT. Survival curves of the two cohorts were similar regardless of EBV reactivation (log-rank, p= 0.201). Discussion: The incidence of EBV reactivation (n= 30; 54%) and of PTLD (n=1;1.7%) were standard compared to previous studies, resulting in a standard specificity of 47% for EBV screening. However, within our limited group of patients, we could not show any significant differences in mortality between the EBV(+) and EBV (−) cohorts. Therefore, absence of preventive treatment for EBV reactivation did not result in an increase in mortality in our EBV reactivating cohort. This suggests that systematic prophylactic use of Rituximab may not affect overall mortality, whilst potentially increasing the risk of other opportunistic infections. Conclusion: Further prospective studies are needed to better define the patients at risk for developing EBV-related PTLD, within the EBV reactivating allogeneic transplant patients group, before prophylactic treatment of reactivation becomes a routine procedure.

scholarly journals A Rapid Antigen Detection Test to Diagnose SARS-CoV-2 Infection Using Exhaled Breath Condensate by A Modified Inflammacheck® Device

Sensors ◽  
2021 ◽  
Vol 21 (17) ◽  
pp. 5710 ◽  
Author(s):  
Mauro Maniscalco ◽  
Pasquale Ambrosino ◽  
Anna Ciullo ◽  
Salvatore Fuschillo ◽  
Valerio Valente ◽  
...  
Keyword(s):  
Diagnostic Accuracy ◽  
Exhaled Breath Condensate ◽  
False Negative ◽  
Antigen Detection ◽  
Routine Practice ◽  
Study Cohort ◽  
Exhaled Breath ◽  
Rt Pcr ◽  
Rapid Antigen Detection Test ◽  
Breath Condensate

Background: The standard test that identifies the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is based on reverse transcriptase-polymerase chain reaction (RT-PCR) from nasopharyngeal (NP) swab specimens. We compared the accuracy of a rapid antigen detection test using exhaled breath condensate by a modified Inflammacheck® device with the standard RT-PCR to diagnose SARS-CoV-2 infection. Methods: We performed a manufacturer-independent, cross-sectional, diagnostic accuracy study involving two Italian hospitals. Sensitivity, specificity, positive (PLR) and negative likelihood ratio (NLR), positive (PPV) and negative predictive value (NPV) and diagnostic accuracy with 95% confidence intervals (95% CI) of Inflammacheck® were calculated using the RT-PCR results as the standard. Further RT-PCR tests were conducted on NP specimens from test positive subjects to obtain the Ct (cycle threshold) values as indicative evidence of the viral load. Results: A total of 105 individuals (41 females, 39.0%; 64 males, 61.0%; mean age: 58.4 years) were included in the final analysis, with the RT-PCR being positive in 13 (12.4%) and negative in 92 (87.6%). The agreement between the two methods was 98.1%, with a Cohen’s κ score of 0.91 (95% CI: 0.79–1.00). The overall sensitivity and specificity of the Inflammacheck® were 92.3% (95% CI: 64.0%–99.8%) and 98.9% (95% CI: 94.1%–100%), respectively, with a PLR of 84.9 (95% CI: 12.0–600.3) and a NLR of 0.08 (95% CI: 0.01–0.51). Considering a 12.4% disease prevalence in the study cohort, the PPV was 92.3% (95% CI: 62.9%–98.8%) and the NPV was 98.9% (95% CI: 93.3%–99.8%), with an overall accuracy of 98.1% (95% CI: 93.3%–99.8%). The Fagan’s nomogram substantially confirmed the clinical applicability of the test in a realistic scenario with a pre-test probability set at 4%. Ct values obtained for the positive test subjects by means of the RT-PCR were normally distributed between 26 and 38 cycles, corresponding to viral loads from light (38 cycles) to high (26 cycles). The single false negative record had a Ct value of 33, which was close to the mean of the cohort (32.5 cycles). Conclusions: The modified Inflammacheck® device may be a rapid, non-demanding and cost-effective method for SARS-CoV-2 detection. This device may be used for routine practice in different healthcare settings (community, hospital, rehabilitation).

scholarly journals Retrospective Evaluation of the Diagnostic Accuracy of the Modified Alvarado Scoring System (MASS) in a Croatian Hospital

2019 ◽  
Vol 48 (2) ◽  
pp. 177
Author(s):  
Branko Bakula ◽  
Vanja Radišić Biljak ◽  
Mirko Bakula ◽  
Fran Rašić ◽  
Ana-Maria Šimundić
Keyword(s):  
Diagnostic Accuracy ◽  
Scoring System ◽  
False Negative ◽  
False Negative Rate ◽  
Scoring Systems ◽  
Negative Appendectomy ◽  
Average Mass ◽  
Suspected Appendicitis ◽  
Significant Difference ◽  
Calculated Mass

<p><strong>Objective. </strong>Diagnosing acute appendicitis (AA) is challenging and this has stimulated surgeons to develop scoring systems that could potentially decrease the rate of misdiagnosis in patients with suspected appendicitis. One of the most widely used today is the Modified Alvarado scoring system (MASS), however its sensitivity and specificity varies a great deal between studies. As a result, we wanted to assess the diagnostic accuracy of MASS retrospectively at our institution to achieve the highest possible value of sensitivity and decrease the number of false negative patients.</p><p><strong>Material and Methods. </strong>We retrospectively calculated MASS for all subsequent patients who had undergone an appendectomy at our institution between July 2015 and March 2017.</p><p><strong>Results. </strong>In 118 out of 146 operated patients, AA was confirmed intraoperatively. There was a statistically significant difference between the average MASS score in the positive and negative appendectomy groups (6 v. 4, respectively, P&lt;0.001), with a significantly higher number of females among the negative appendectomies (P&lt;0.001). When lowering the cut-off to a value as low as ≥3, the sensitivity of the MASS score increased to 97.45% (95% CI: 92.7 – 99.5), thus obtaining a very low false negative rate of merely 2.55%.</p><p><strong>Conclusion. </strong>This retrospective diagnostic accuracy study confirmed the higher average MASS score in the group of patients with confirmed AA diagnosis. A MASS score above the proposed low cut-off value (≥3) can be a useful tool to help surgeons ruling in patients with AA in order to reduce the risk of missing diagnosis.</p>

scholarly journals Which Modality Should Be Integrated to Increase the Diagnostic Efficiency of BI-RADS 0, 3, and 4 Lesions? Ultrasonography or Digital Breast Tomosynthesis?

2021 ◽  
Vol In Press (In Press) ◽  
Author(s):  
Zeynep Fatma Arslan ◽  
Aysegul Altunkeser ◽  
Nergis Aksoy ◽  
Muslu Kazım Korez ◽  
Ethem Omeroglu
Keyword(s):  
Diagnostic Accuracy ◽  
False Negative ◽  
Digital Breast Tomosynthesis ◽  
Dense Breast ◽  
Diagnostic Efficiency ◽  
Breast Tomosynthesis ◽  
Breast Parenchyma ◽  
Dense Breasts ◽  
Negative Results ◽  
Significant Difference

Background: Digital mammography (DM) is one of the most common and effective radiological methods for breast cancer screening and detection. A dense fibroglandular breast tissue can lead to false negative results by superimposing on the lesion margins. Therefore, adjunctive imaging methods, such as digital breast tomosynthesis (DBT) and ultrasonography (US), are needed to increase mammographic sensitivity. Objectives: This study aimed to examine the contribution of US and DBT to DM in different patient groups (patients group of BI-RADS 0 and 3-4 lesions, patients with dense breast parenchyma, patients with non-dense breast parenchyma).. Whether US and DBT can upgrade or downgrade the BI-RADS category of uncertain lesions detected on DM was also investigated. Patients and Methods: Forty-six patients, who were classified as BI-RADS categories 0, 3, and 4 in DM, according to DBT and US findings, were included in the study. DM followed by DBT was performed for the patients, and the BI-RADS classification system was applied. Subsequently, the patients were evaluated sonographically, and the BI-RADS system was applied according to the US results. Each BI-RADS category was compared with the histopathological and multimodality follow-up results. The diagnostic performance of all modalities was also examined alone and in combination. Results: The sensitivity and specificity of DM alone was 42% and 87%, respectively. DBT detected the lesions with 92% sensitivity and 68% specificity. The modality with the highest sensitivity for the detection of malignant lesions was US (100%). Besides, the specificity of DBT was significantly high for dense breasts (P < 0.001). There was no significant difference in terms of the diagnostic accuracy of US measurements between dense and non-dense breasts. For indeterminate lesions, the integration of DBT and US to DM increased the diagnostic accuracy. Conclusion: The contribution of DBT is more valuable than US in patients with dense breast parenchyma.

scholarly journals Chlamydia Trachomatis Infection as a Risk Factor of Infertility in Women

2021 ◽  
pp. 63-70
Author(s):  
Mohamed A. Sharaf ◽  
Shereen B. El-Bohoty ◽  
Hossam A. Hodeib ◽  
Dina G. El-Kholi
Keyword(s):  
Chlamydia Trachomatis ◽  
Statistical Significance ◽  
Developed Countries ◽  
Female Reproductive Tract ◽  
Secondary Infertility ◽  
Randomized Clinical Study ◽  
Group I ◽  
Significant Difference ◽  
Tubal Factor ◽  
Group Ii

Background: C. trachomatis is known to cause damage to the female reproductive tract, primarily due to adhesions or obstructions of the fallopian tubes secondary to the inflammatory response. Tubal Factor of Infertility (TFI) is the main cause of infertility in 10-30% of cases in developed countries and C. trachomatis is the most common causative agent to TFI in the developed world. The aim of this study was to investigate the possible role of the chlamydial serology as a screening test for tubal infertility, by the detection of the anti-chlamydial IgG antibodies by using E.L.I.S.A. and study the benefit of using non-invasive methods to diagnose chlamydial infection. Materials and Methods: This prospective randomized clinical study was conducted on a (50) women complaining of Infertility due to Tubal Factor. The patient was randomly classified into two groups: (50)Group I: complaining primary or secondary infertility. Group II: including (25) patients pregnant and came for Antenatal care Results: Prevalence of different types of tubal factor in the study population was 12% in Distal block (DB), 10% Distal block plus peritubal adhesions (DB + PTA), 40% Hydrosalpinx (HS), 8% Hydrosalpinx plus peritubal adhesions (HS + PTA), 26% Proximal block (PB), 4% Peritubal adhesions (PTA). serum antichlamydial IgG level was significantly higher among group I (8.62 ±1.4) than group II (2.11±0.82). Also, 46% of group I had serum antichlamydial IgG positive vs. (12%) in group II with significant difference. Comparing positive C. trachomatis IgG with type of infertility, a total of 13 (57.7%) of those with primary infertility and 10 (42.3%) of those with secondary infertility tested positive. The difference was of no statistical significance (P=0.725). Conclusion: We can conclude that, Chlamydia trachomatis is a major factor in female infertility especially for tubal factor of infertility, serum Chlamydia trachomatis IgG assay could be used a predictive factor for tubal factor infertility.

scholarly journals A risk stratification approach for improved interpretation of diagnostic accuracy statistics

2016 ◽  
Author(s):  
Hormuzd A. Katki ◽  
Mark Schiffman
Keyword(s):  
Public Health ◽  
Risk Stratification ◽  
Diagnostic Accuracy ◽  
Area Under The Curve ◽  
Population Based ◽  
Screening Tests ◽  
Predictive Values ◽  
The Usa ◽  
Relative Gains ◽  
Youden’S Index

AbstractDiagnostic accuracy statistics, including predictive values, risk-differences, Youden’s index and Area Under the Curve (AUC), assess the promise of novel biomarkers proposed as diagnostic tests. We reinterpret these statistics in light of risk-stratification (how well a biomarker separates those at higher risk from those at lower risk) to better understand their implications for public-health programs. We introduce an intuitively simple statistic, Mean Risk Stratification (MRS): the average change in risk (pre-test vs. post-test) revealed for tested individuals. High MRS implies better risk separation achieved by testing. MRS demonstrates that conventional predictive values can mislead because they do not account for disease prevalence or test-positivity rates. Little risk-stratification is possible for rare diseases, demonstrating a “high-bar” to justify population-based screening. Importantly, we demonstrate that the risk-difference, Youden’s index, and AUC measure only multiplicative relative gains in risk-stratification: AUC=0.6 achieves only 20% of maximum risk-stratification (AUC=0.9 achieves 80%). However, large relative gains in risk-stratification might not imply large absolute gains if disease is rare or if the test is rarely positive. We illustrate MRS by our experience comparing the performance of cervical cancer screening tests in China vs. the USA. The test with the worst AUC=0.72 in China (visual inspection with ascetic acid) provides twice the risk-stratification of the test with best AUC=0.83 in the USA (human papillomavirus and Pap cotesting) because China has three times more cervical precancer/cancer. MRS could be routinely calculated to better understand the clinical/public-health implications of standard diagnostic accuracy statistics.

scholarly journals Evaluating Ten Commercially-Available SARS-CoV-2 Rapid Serological Tests Using the STARD (Standards for Reporting of Diagnostic Accuracy Studies) Method.

2020 ◽  
Author(s):  
Laurent Dortet ◽  
Jean-Baptiste Ronat ◽  
Christelle Vauloup-Fellous ◽  
Céline Langendorf ◽  
David-Alexis Mendels ◽  
...  
Keyword(s):  
Diagnostic Accuracy ◽  
Viral Infection ◽  
False Negative ◽  
Rheumatoid Factors ◽  
Sample Collection ◽  
Rt Pcr ◽  
Serological Tests ◽  
Immunological Status ◽  
Health Authorities ◽  
Specificity And Sensitivity

Numerous SARS-CoV-2 rapid serological tests have been developed, but their accuracy has usually been assessed using very few samples, and rigorous comparisons between these tests are scarce. In this study, we evaluated and compared 10 commercially-available SARS-CoV-2 rapid serological tests using the STARD methodology (Standards for Reporting of Diagnostic Accuracy Studies). 250 sera from 159 PCR-confirmed SARS-CoV-2 patients (collected from 0 to 32 days after onset of symptoms) were tested with rapid serological tests. Control sera (N = 254) were retrieved from pre-COVID periods from patients with other coronavirus infections (N = 11), positive rheumatoid factors (N = 3), IgG/IgM hyperglobulinemia (N = 9), malaria (n = 5), or no documented viral infection (N = 226). All samples were tested using rapid lateral flow immunoassays (LFIA) from 10 manufacturers. Only four tests achieved ≥98% specificity, with other tests ranging from 75.7%-99.2%. Sensitivities varied by the day of sample collection, from 31.7%-55.4% (Days 0-9), 65.9%-92.9% (Days 10-14), and 81.0%-95.2% (>14 days) after the onset of symptoms, respectively. Only three tests evaluated met French Health Authorities’ thresholds for SARS-CoV-2 serological tests (≥90% sensitivity + ≥98% specificity). Overall, the performances between tests varied greatly, with only a third meeting acceptable specificity and sensitivity thresholds. Knowing the analytical performance of these tests will allow clinicians and most importantly laboratorians to use them with more confidence, could help determine the general population’s immunological status, and may help to diagnose some patients with false-negative RT-PCR results.

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