positive predictive value
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2022 ◽  
Vol 38 (3) ◽  
Author(s):  
Madeeha Rehan ◽  
Attika Khalid ◽  
Fariha Nasreen

Background & Objective: Undiagnosed malarial infectionis associated with significant mortality and morbidity. Laboratory investigations leading to rapid, accurate and timely diagnosis of malaria is still a challenge. This study was done to assess the utility of abnormal White blood cell differential fluorescence (WDF) scattergram for diagnosis of malaria. Our aim was to study the utility of WDF scattergram for early detection of malarial parasite. Methods: All EDTA anti-coagulated blood samples received in laboratory during a period from Dec 2019 to May 2020 were analyzed on anautomated hematology analyzer, Sysmex XN 1000. All abnormal WDF scattergrams pertaining to plasmodium specie were critically evaluated and recorded. Review of Leishman-stained peripheral smears as well as immune-chromatographic assay by rapid test devices (RTD) was done. Accordingly, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for detection of malaria by abnormal scattergram were calculated. Results: Out of total 1, 26,000of samples analyzed, abnormal WDF scattergrams were detected in 96 cases. Amongst these, 95.8% (92) were positive for MP on Leishman-stained peripheral smear as well as on ICT with a p-value of 0.05. WDF scattergram abnormalities typical of malaria showed a sensitivity of 80% and specificity of 93.26%. Positive predictive value of 95.8% whereas negative predictive value of 99.9% was detected. Significant findings of hemolysis, platelet clumps, nucleated RBCS (NRBCs) and RBC agglutination were noted in cases (n=4) with abnormal WDF scattergram negative for malaria on peripheral smear. Conclusion: Interpretation of abnormal WDF scattergram not only increases the early detection rate for malarial parasite but isa strong indicator for presence of hemolysis, RBC agglutination, platelet clumps and leucoerythroblastic blood picture as well. doi: https://doi.org/10.12669/pjms.38.3.4702 How to cite this:Rehan M, Khalid A, Nasreen F. White blood cell differential fluorescence abnormal scattergram: A useful indicator for early detection of malarial parasite. Pak J Med Sci. 2022;38(3):---------. doi: https://doi.org/10.12669/pjms.38.3.4702 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


2022 ◽  
pp. emermed-2021-211823
Author(s):  
Keita Shibahashi ◽  
Kazuhiro Sugiyama ◽  
Takuto Ishida ◽  
Yuichi Hamabe

BackgroundThe duration from collapse to initiation of cardiopulmonary resuscitation (no-flow time) is one of the most important determinants of outcomes after out-of-hospital cardiac arrest (OHCA). Initial shockable cardiac rhythm (ventricular fibrillation or ventricular tachycardia) is reported to be a marker of short no-flow time; however, there is conflicting evidence regarding the impact of initial shockable cardiac rhythm on treatment decisions. We investigated the association between initial shockable cardiac rhythm and the no-flow time and evaluated whether initial shockable cardiac rhythm can be a marker of short no-flow time in patients with OHCA.MethodsPatients aged 18 years and older experiencing OHCA between 2010 and 2016 were selected from a nationwide population-based Japanese database. The association between the no-flow time duration and initial shockable cardiac rhythm was evaluated. Diagnostic accuracy was evaluated using the sensitivity, specificity and positive predictive value.ResultsA total of 177 634 patients were eligible for the analysis. The median age was 77 years (58.3%, men). Initial shockable cardiac rhythm was recorded in 11.8% of the patients. No-flow time duration was significantly associated with lower probability of initial shockable cardiac rhythm, with an adjusted OR of 0.97 (95% CI 0.96 to 0.97) per additional minute. The sensitivity, specificity and positive predictive value of initial shockable cardiac rhythm to identify a no-flow time of <5 min were 0.12 (95% CI 0.12 to 0.12), 0.88 (95% CI 0.88 to 0.89) and 0.35 (95% CI 0.34 to 0.35), respectively. The positive predictive values were 0.90, 0.95 and 0.99 with no-flow times of 15, 18 and 28 min, respectively.ConclusionsAlthough there was a significant association between initial shockable cardiac rhythm and no-flow time duration, initial shockable cardiac rhythm was not reliable when solely used as a surrogate of a short no-flow time duration after OHCA.


2022 ◽  
Vol 93 ◽  
pp. 229-233
Author(s):  
Hans Peter Bögl ◽  
Georg Zdolsek ◽  
Lukas Barnisin ◽  
Michael Möller ◽  
Jörg Schilcher

Background and purpose — To continuously assess the incidence of atypical femoral fractures (AFFs) in the population is important, to allow the evaluation of the risks and benefits associated with osteoporosis treatment. Therefore, we investigated the possibility to use the Swedish Fracture Register (SFR) as a surveillance tool for AFFs in the population and to explore means of improvement. Patients and methods — All AFF registrations in the SFR from January 1, 2015 to December 31, 2018 were enrolled in the study. For these patients, radiographs were obtained and combined with radiographs from 176 patients with normal femoral fractures, to form the study cohort. All images were reviewed and classified into AFFs or normal femur fractures by 2 experts in the field (gold-standard classification) and 1 orthopedic resident educated on the specific radiographic features of AFF (educated-user classification). Furthermore, we estimated the incidence rate of AFFs in the population captured by the register through comparison with a previous cohort and calculated the positive predictive value (PPV) and, where possible, the inter-observer agreement (Cohen’s kappa) between the different classifications. Results — Of the 178 available patients with AFF in the SFR, 104 patients were classified as AFF using the goldstandard classification, and 89 using the educated-user classification. The PPV increased from 0.58 in the SFR classification to 0.93 in the educated-user classification. The interobserver agreement between the gold-standard classification and the educated-user classification was 0.81. Interpretation — With a positive predictive value of 0.58 the Swedish Fracture Register outperforms radiology reports and reports to the Swedish Medical Products Agency on adverse drug reactions as a diagnostic tool to identify atypical femoral fractures.


2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Ji-Bin Li ◽  
Zhi-Yu Qiu ◽  
Yu-Xiang Deng ◽  
Yin Li ◽  
Zhuo-Chen Lin ◽  
...  

Abstract Background The positive predictive value (PPV) of high risk factor questionnaire (HRFQ) plus fecal immunochemical test (FIT) as preliminary screening strategy for colorectal-related neoplasia is relatively low. We aim to explore independent factors associated with PPVs of HRFQ combined FIT for selecting high risk individuals for colonoscopy. Methods A total of 6971 residents were enrolled in a community-based screening program. Participants who had positive results of HRFQ and/or FIT and subsequently received colonoscopy were involved. The associations of socio-demographic factors, lifestyle behaviors, and high risk factors of colorectal cancer with PPVs of HRFQ, FIT, and their combination were evaluated by multivariable logistic regression models. Results Among 572 involved cases, 249 (43.5%) colorectal neoplasms were detected by colonoscopy, including 71 advanced adenoma (12.4%) and 9 colorectal cancer (CRC) (1.6%). The PPVs of preliminary screening were 43.5% for total colorectal neoplasms, 14.0% for advanced neoplasm, and 1.6% for CRC. Adding positive HRFQ to FIT could improve the PPV from 3.5 to 8.0% for detecting CRC. Preliminarily screened positive individuals who were males [adjusted odds ratio (AOR): 1.95, 95% CI 1.31, 2.90; p  < 0.001], elders (> 60 years) (AOR: 1.70, 95% CI 1.17, 2.46; p  = 0.005), or ex-/current smokers (AOR: 3.04, 95% CI 1.31, 7.09; p  = 0.10) had higher odds of PPVs of detecting colorectal neoplasms. Conclusions Combining HRFQ and FIT could largely improve PPVs for screening advanced neoplasm and CRC. Gender and age-specific FIT cut-off values as well as initiating ages for CRC screening might be recommended to improve the accuracy and effectiveness of current screening algorithm.


2022 ◽  
Vol 22 (1) ◽  
Author(s):  
Jacques Balayla

Abstract Background Bayes’ theorem confers inherent limitations on the accuracy of screening tests as a function of disease prevalence. Herein, we establish a mathematical model to determine whether sequential testing with a single test overcomes the aforementioned Bayesian limitations and thus improves the reliability of screening tests. Methods We use Bayes’ theorem to derive the positive predictive value equation, and apply the Bayesian updating method to obtain the equation for the positive predictive value (PPV) following repeated testing. We likewise derive the equation which determines the number of iterations of a positive test needed to obtain a desired positive predictive value, represented graphically by the tablecloth function. Results For a given PPV ($$\rho$$ ρ ) approaching k, the number of positive test iterations needed given a prevalence of disease ($$\phi$$ ϕ ) is: $$n_i =\lim _{\rho \rightarrow k}\left\lceil \frac{ln\left[ \frac{\rho (\phi -1)}{\phi (\rho -1)}\right] }{ln\left[ \frac{a}{1-b}\right] }\right\rceil \qquad \qquad (1)$$ n i = lim ρ → k l n ρ ( ϕ - 1 ) ϕ ( ρ - 1 ) l n a 1 - b ( 1 ) where $$n_i$$ n i = number of testing iterations necessary to achieve $$\rho$$ ρ , the desired positive predictive value, ln = the natural logarithm, a = sensitivity, b = specificity, $$\phi$$ ϕ = disease prevalence/pre-test probability and k = constant. Conclusions Based on the aforementioned derivation, we provide reference tables for the number of test iterations needed to obtain a $$\rho (\phi )$$ ρ ( ϕ ) of 50, 75, 95 and 99% as a function of various levels of sensitivity, specificity and disease prevalence/pre-test probability. Clinical validation of these concepts needs to be obtained prior to its widespread application.


2022 ◽  
Vol 2022 ◽  
pp. 1-8
Author(s):  
Zhenxing Yu ◽  
Guixue Ou ◽  
Ruihua Wang ◽  
Qinghua Zhang

The study focused on the clinical application value of artificial intelligence-based computed tomography angiography (CTA) in the diagnosis of orthotopic liver transplantation (OLT) after ischemic type biliary lesions (ITBL). A total of 66 patients receiving OLT in hospital were selected. Convolutional neural network (CNN) algorithm was used to denoise and detect the edges of CTA images of patients. At the same time, the quality of the processed image was subjectively evaluated and quantified by Hmax, Ur, Cr, and other indicators. Then, the digital subtraction angiography (DSA) diagnosis and CTA diagnosis based on CNN were compared for the sensitivity, specificity, positive predictive value, negative predictive value, and patient classification results. It was found that CTA can clearly reflect the information of hepatic aorta lesions and thrombosis in patients with ischemic single-duct injury after liver transplantation. After neural network algorithm processing, the image quality is obviously improved, the lesions are more prominent, and the details of lesion parts are also well displayed. ITBL occurred in 40 (71%) of 56 patients with abnormal CTA at early stage. ITBL occurred in only 8 (12.3%) of 65 patients with normal CTA at early stage. Early CTA manifestations had high sensitivity (72.22%), specificity (87.44%), positive predictive value (60.94%), and negative predictive value (92.06%) for the diagnosis of ITBL. It was concluded that artificial intelligence-based CTA had high clinical application value in the diagnosis of ITBL after OLT.


Author(s):  
Mehdi Ashik Chowdhury ◽  
Asim Ranjan Barua ◽  
- Asaduzzaman ◽  
Mohammad Mahabubul Hoque ◽  
DM Arifur Rahman

Background: Cervical cancer screening can actually prevent most cervical cancers and also facilitates early detection which allows fruitful treatment.Objective: To evaluate and compare the efficacy of Liquid-based cytology (LBC) with conventional Pap smear test.Methods: This crosssectional study was conducted between March 2015 and June 2017. A total of 72 women participated in this study attending the Out-Patient Department (OPD) of Gynaecology (Colposcopy Clinic) of Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, Bangladesh, for VIA test. The smears prepared by the conventional Pap smear method and Liquid-based cytology method were observed by two independent observers in Department of Pathology of the same institution.Results: The mean age of the patients was 40.22±12.29 years. Considering histopathology as gold standard, in conventional Pap smear preparation our data suggested its sensitivity 87.5%, specificity 92.2%, accuracy 91.7%, positive predictive value 58.3% and negative predictive value 98.3%. In contrast, in Liquid-based cytology, we found its sensitivity 75.0%, specificity 90.6%, accuracy 88.9%, positive predictive value 50.0% and negative predictive value 96.7%.Conclusion: LBC has practical advantages over conventional preparation by producing monolayer of cells, smaller area to screen, reproducibility and availability of doing adjunct molecular techniques from residual sample. However, conventional preparation shows better sensitivity and positive predictive value and almost similar specificity, negative predictive value and accuracy with LBC.International Journal of Human and Health Sciences Vol. 06 No. 01 January’22 Page: 36-40


2022 ◽  
Author(s):  
Hamzah Abdul Majid Serag ◽  
Ali Muhammad Ali Rushdi

We provide a novel method for validating any purported set of the four most prominent indicators of diagnostic testing (Sensitivity, Specificity, Positive Predictive Value, and Negative Predictive Value), by observing that these indicators constitute three rather than four independent quantities. This observation has virtually been unheard of in the open medical literature. We defined two functions, which serve as consistency criteria, since each of them checks consistency for any set of four numerical values claimed to be the four basic diagnostic indicators. Most of the data we came across in various Saudi medical journals met our criteria for consistency, but in a few cases, there were obvious unexplained blunders. We relate our present findings to the more general issue of detection and ramifications of flawed, fabricated or wrong data. We observe that the research field handling the detection of flawed data is still in its infancy, and hope that this field will reach maturity very soon.


2022 ◽  
Vol 95 (1129) ◽  
Author(s):  
Anna Sára Kardos ◽  
Judit Simon ◽  
Chiara Nardocci ◽  
István Viktor Szabó ◽  
Norbert Nagy ◽  
...  

Objective: To determine the diagnostic accuracy of a deep-learning (DL)-based algorithm using chest computed tomography (CT) scans for the rapid diagnosis of coronavirus disease 2019 (COVID-19), as compared to the reference standard reverse-transcription polymerase chain reaction (RT-PCR) test. Methods: In this retrospective analysis, data of COVID-19 suspected patients who underwent RT-PCR and chest CT examination for the diagnosis of COVID-19 were assessed. By quantifying the affected area of the lung parenchyma, severity score was evaluated for each lobe of the lung with the DL-based algorithm. The diagnosis was based on the total lung severity score ranging from 0 to 25. The data were randomly split into a 40% training set and a 60% test set. Optimal cut-off value was determined using Youden-index method on the training cohort. Results: A total of 1259 patients were enrolled in this study. The prevalence of RT-PCR positivity in the overall investigated period was 51.5%. As compared to RT-PCR, sensitivity, specificity, positive predictive value, negative predictive value and accuracy on the test cohort were 39.0%, 80.2%, 68.0%, 55.0% and 58.9%, respectively. Regarding the whole data set, when adding those with positive RT-PCR test at any time during hospital stay or “COVID-19 without virus detection”, as final diagnosis to the true positive cases, specificity increased from 80.3% to 88.1% and the positive predictive value increased from 68.4% to 81.7%. Conclusion: DL-based CT severity score was found to have a good specificity and positive predictive value, as compared to RT-PCR. This standardized scoring system can aid rapid diagnosis and clinical decision making. Advances in knowledge: DL-based CT severity score can detect COVID-19-related lung alterations even at early stages, when RT-PCR is not yet positive.


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