scholarly journals Novel Radiographic Indexes for Elbow Stability Assessment: Part A—Cadaveric Validation

2021 ◽  
Author(s):  
Francesco Luceri ◽  
Davide Cucchi ◽  
Enrico Rosagrata ◽  
Carlo Eugenio Zaolino ◽  
Marco Viganò ◽  
...  
Keyword(s):  
Diagnostic Accuracy ◽  
Pathological Condition ◽  
High Sensitivity ◽  
Elbow Instability ◽  
Level Of Evidence ◽  
Coronoid Fracture ◽  
Proximal Ulna ◽  
Sigmoid Notch ◽  
Fresh Frozen ◽  
Coronoid Fractures

Abstract Introduction Elbow bony stability relies primarily on the high anatomic congruency between the humeral trochlea and the ulnar greater sigmoid notch. No practical tools are available to distinguish different morphotypes of the proximal ulna and herewith predict elbow stability. The aim of this study was to assess inter-observer reproducibility, evaluate diagnostic performance and determine responsiveness to change after simulated coronoid process fracture for three novel elbow radiographic indexes. Methods Ten fresh-frozen cadaver specimens of upper limbs from human donors were available for this study. Three primary indexes were defined, as well as two derived angles: Trochlear Depth Index (TDI); Posterior Coverage Index (PCI); Anterior Coverage Index (ACI); radiographic coverage angle (RCA); olecranon–diaphisary angle (ODA). Each index was first measured on standardized lateral radiographs and subsequently by direct measurement after open dissection. Finally, a type II coronoid fracture (Regan and Morrey classification) was created on each specimen and both radiographic and open measurements were repeated. All measurements were conducted by two orthopaedic surgeons and two dedicated musculoskeletal radiologists. Results All three indexes showed good or moderate inter-observer reliability and moderate accuracy and precision when compared to the gold standard (open measurement). A significant change between the radiographic TDI and ACI before and after simulated coronoid fracture was observed [TDI: decrease from 0.45 ± 0.03 to 0.39 ± 0.08 (p = 0.035); ACI: decrease from 1.90 ± 0.17 to 1.58 ± 0.21 (p = 0.001)]. As expected, no significant changes were documented for the PCI. Based on these data, a predictive model was generated, able to identify coronoid fractures with a sensitivity of 80% and a specificity of 100%. Conclusion New, simple and easily reproducible radiological indexes to describe the congruency of the greater sigmoid notch have been proposed. TDI and ACI change significantly after a simulated coronoid fracture, indicating a good responsiveness of these parameters to a pathological condition. Furthermore, combining TDI and ACI in a regression model equation allowed to identify simulated fractures with high sensitivity and specificity. The newly proposed indexes are, therefore, promising tools to improve diagnostic accuracy of coronoid fractures and show potential to enhance perioperative diagnostic also in cases of elbow instability and stiffness. Level of evidence Basic science study. Clinical relevance The newly proposed indexes are promising tools to improve diagnostic accuracy of coronoid fractures as well as to enhance perioperative diagnostic for elbow instability and stiffness.

Injuries to the Coronoid Process of the Ulna with Involvement of the Lesser Sigmoid Notch

2020 ◽  
Author(s):  
Valentin Rausch ◽  
Sina Neugebauer ◽  
Tim Leschinger ◽  
Lars Müller ◽  
Kilian Wegmann ◽  
...  
Keyword(s):  
Fragment Size ◽  
Coronoid Process ◽  
Annular Ligament ◽  
Concomitant Injuries ◽  
Proximal Ulna ◽  
Sigmoid Notch ◽  
Coronoid Fractures ◽  
The Mean ◽  
The Stability ◽  
Arthritic Changes

Abstract Introduction This study aimed to describe the involvement of the lesser sigmoid notch in fractures to the coronoid process. We hypothesized that injuries to the lateral aspect of the coronoid process regularly involve the annular ligament insertion at the anterior lesser sigmoid notch. Material and Methods Patients treated for a coronoid process fracture at our institution between 06/2011 and 07/2018 were included. We excluded patients < 18 years, patients with arthritic changes or previous operative treatment to the elbow, and patients with concomitant injuries to the proximal ulna. In patients with involvement of the lesser sigmoid notch, the coronoid height and fragment size (anteroposterior, mediolateral, and craniocaudal) were measured. Results Seventy-two patients (mean age: 47 years ± 17.6) could be included in the study. Twenty-one patients (29.2%) had a fracture involving the lateral sigmoid notch. The mean anteroposterior fragment length was 7 ± 1.6 mm. The fragment affected a mean of 43 ± 10.8% of the coronoid height. The mean mediolateral size of the fragment was 10 ± 5.0 mm, and the mean cranio-caudal size was 7 ± 2.7 mm. Conclusion Coronoid fractures regularly include the lesser sigmoid notch. These injuries possibly affect the anterior annular ligament insertion which is important for the stability of the proximal radioulnar joint and varus stability of the elbow.

Greater sigmoid notch dysplasia causing elbow instability: Lateral ligament reconstruction and Stamp osteotomy

2021 ◽  
pp. 175857322098785
Author(s):  
Aparna Viswanath ◽  
Jill L Thomas ◽  
Adam C Watts
Keyword(s):  
Ligament Reconstruction ◽  
Iliac Crest ◽  
Lateral Ligament ◽  
Iliac Crest Bone Graft ◽  
Elbow Instability ◽  
Radiographic Outcome ◽  
Level Of Evidence ◽  
Opening Wedge ◽  
Sigmoid Notch ◽  
Buttress Plate

The coronoid is one of the elbow’s primary static stabilisers, and the importance of reconstruction following fracture with instability has been established. In the developing elbow, instability can lead to greater sigmoid notch dysplasia that can make reconstruction challenging. A novel technique to improve osseous stability with an opening wedge ‘stamp osteotomy’ reconstruction of the coronoid is described combined with a lateral ligament reconstruction, in two patients with recurrent posteromedial rotatory instability. The technique improves congruity and coverage of the greater sigmoid notch with the trochlea whilst maintaining articular cartilage. Extra-articular iliac crest bone graft is used to maintain the position with buttress plate support. The surgical technique is described and the clinical and radiographic outcome reported in two patients. Level of evidence: IV.

Features of Thrombi and Diagnostic Accuracy of Impedance Plethysmography in Symptomatic and Asymptomatic Deep Vein Thrombosis

1993 ◽  
Vol 70 (02) ◽  
pp. 266-269 ◽  
Author(s):  
Giancarlo Agnelli ◽  
Benilde Cosmi ◽  
Stefano Radicchia ◽  
Franca Veschi ◽  
Enrico Boschetti ◽  
...  
Keyword(s):  
Deep Vein Thrombosis ◽  
Diagnostic Accuracy ◽  
High Sensitivity ◽  
Impedance Plethysmography ◽  
Surveillance Programme ◽  
Vein Thrombosis ◽  
Asymptomatic Patients ◽  
High Prevalence ◽  
The Mean ◽  
Deep Vein

SummaryImpedance plethysmography (IPG) has high sensitivity and specificity in patients with symptomatic deep vein thrombosis (DVT) while it fails to detect asymptomatic DVT. The aim of this study was to determine whether the features of thrombi such as location, size and occlusiveness could explain the different accuracy of IPG in symptomatic and asymptomatic DVT patients. One-hundred and seventeen consecutive outpatients with a clinical suspicion of DVT and 246 consecutive patients undergoing hip surgery were admitted to the study. In symptomatic patients IPG was performed on the day of referral, followed by venography, while in asymptomatic patients IPG was performed as a surveillance programme, followed by bilateral venography.A venography proved DVT was observed in 37% of the symptomatic patients and 34% of the asymptomatic limbs. A significantly higher proportion of proximal DVTs was found in symptomatic patients than in asymptomatic patients (78% vs 46%; p = 0.001). The mean Marder score, taken as an index of thrombus size, was significantly higher in symptomatic patients than in asymptomatic patients (19.0 vs 9.6; p = 0.0001). A significantly higher proportion of occlusive DVTs was observed in symptomatic than in asymptomatic patients (69% vs 36%; p = 0.001).We conclude that the unsatisfactory diagnostic accuracy of IPG in asymptomatic DVT is due to the high prevalence of distal, small and non occlusive thrombi. Such thrombi are unlikely to cause a critical obstruction of the venous outflow and therefore to produce a positive IPG.

scholarly journals Deep learning systems detect dysplasia with human-like accuracy using histopathology and probe-based confocal laser endomicroscopy

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shan Guleria ◽  
Tilak U. Shah ◽  
J. Vincent Pulido ◽  
Matthew Fasullo ◽  
Lubaina Ehsan ◽  
...  
Keyword(s):  
Deep Learning ◽  
Diagnostic Accuracy ◽  
High Sensitivity ◽  
Confocal Laser Endomicroscopy ◽  
Confocal Laser ◽  
Learning Approaches ◽  
Learning Models ◽  
Whole Slide Image ◽  
Slide Image ◽  
Level Model

AbstractProbe-based confocal laser endomicroscopy (pCLE) allows for real-time diagnosis of dysplasia and cancer in Barrett’s esophagus (BE) but is limited by low sensitivity. Even the gold standard of histopathology is hindered by poor agreement between pathologists. We deployed deep-learning-based image and video analysis in order to improve diagnostic accuracy of pCLE videos and biopsy images. Blinded experts categorized biopsies and pCLE videos as squamous, non-dysplastic BE, or dysplasia/cancer, and deep learning models were trained to classify the data into these three categories. Biopsy classification was conducted using two distinct approaches—a patch-level model and a whole-slide-image-level model. Gradient-weighted class activation maps (Grad-CAMs) were extracted from pCLE and biopsy models in order to determine tissue structures deemed relevant by the models. 1970 pCLE videos, 897,931 biopsy patches, and 387 whole-slide images were used to train, test, and validate the models. In pCLE analysis, models achieved a high sensitivity for dysplasia (71%) and an overall accuracy of 90% for all classes. For biopsies at the patch level, the model achieved a sensitivity of 72% for dysplasia and an overall accuracy of 90%. The whole-slide-image-level model achieved a sensitivity of 90% for dysplasia and 94% overall accuracy. Grad-CAMs for all models showed activation in medically relevant tissue regions. Our deep learning models achieved high diagnostic accuracy for both pCLE-based and histopathologic diagnosis of esophageal dysplasia and its precursors, similar to human accuracy in prior studies. These machine learning approaches may improve accuracy and efficiency of current screening protocols.

scholarly journals Influence of peracetic acid-ethanol sterilisation on the biomechanical properties of human meniscus transplants

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Volker Eras ◽  
Josefine Graffunder ◽  
Norus Ahmed ◽  
Jan C. Brune
Keyword(s):  
Peracetic Acid ◽  
Biomechanical Properties ◽  
Bone Block ◽  
Test Device ◽  
Level Of Evidence ◽  
Load To Failure ◽  
Graft Extrusion ◽  
Fresh Frozen ◽  
Failure Loads ◽  
N Loading

Abstract Purpose Meniscus allograft transplantation (MAT) is a possible treatment for patients suffering with pain after meniscectomy. Here, peracetic acid (PAA) sterilised meniscus transplants were investigated on whether they would provide an adequate alternative to fresh-frozen transplants in their viscoelastic and mechanical properties. Methods In this analysis, 31 menisci donors (26 male and 5 female) were included. The average donor age was 49.87 years, ranging from 32 to 65 years. Menisci of matched pairs of knees underwent chemical sterilisation while counterparts were left fresh-frozen. Stiffness and load to failure were determined via suture retention. Further menisci were analysed while attached to the tibial bone block using a novel test device to mimic physiological load distribution. Meniscus relaxation, stiffness and failure loads were determined. Histology and biphasic properties of the menisci were examined and results were analysed using paired t-tests. Results A novel custom built test device allowed the application of physiological loads for suture retention testing and revealed no significant differences between PAA sterilised (14.85 ± 4.46 N/mm, 50.49 ± 17.01 N) and fresh-frozen (18.26 ± 4.46 N/mm, 59.49 ± 21.07 N) regarding stiffness and failure load, respectively. Furthermore, initial 200 N loading showed significantly higher strain in sterilised menisci (18.87 ± 1.56) compared to fresh frozen (13.81 ± 1.04). Load relaxation experiments demonstrated significantly lower relaxation for sterilised menisci (77.71 ± 1.62) compared to fresh-frozen (89.11 ± 1.00, p-value < 0.0001). Conclusion Peracetic acid sterilised human menisci performed equally to fresh-frozen counterparts in a suture retention test and in physiological failure testing providing an adequate alternative. However, meniscus relaxation, biphasic properties and strain were shown to be significantly different between the groups. A common problem of MAT is graft extrusion or shrinkage, therefore the parameters measured here should be considered and may influence meniscus extrusion after transplantation. Level of evidence n/a (experimental study)

scholarly journals Quantification and Comparison of Talar Exposure Utilizing a Posteromedial Approach and Medial Malleolar Osteotomy

2021 ◽  
Vol 6 (2) ◽  
pp. 247301142110126
Author(s):  
Jeffrey Donahue ◽  
Ademola Shofoluwe ◽  
Kurt Krautmann ◽  
Emilio Grau-Cruz ◽  
Stephen Becher ◽  
...  
Keyword(s):  
Surface Area ◽  
Digital Image ◽  
National Institutes Of Health ◽  
Level Of Evidence ◽  
Posterior Process ◽  
Medial Malleolar Osteotomy ◽  
Fresh Frozen ◽  
Average Quantity ◽  
Operative Fixation ◽  
Imagej Software

Background: Fractures of the talus are a rare but challenging injury. This study sought to quantify the area of osseous exposure afforded by a posteromedial approach to the talus and medial malleolar osteotomy. Methods: Five fresh-frozen cadaveric lower extremities were dissected using a posteromedial approach and medial malleolar osteotomy respectively. Following exposure, the talar surfaces directedly visualized were marked and captured using a calibrated digital image. The digital images were then analyzed using ImageJ software (National Institutes of Health) to calculate the surface area of the exposure. Results: The average square area of talus exposed using the posteromedial approach was 9.70 cm2 (SD = 2.20, range 7.20-12.46). The average quantity of talar exposure expressed as a percentage was 9% (SD = 1.58, range 7.03-10.40). The average square area of talus exposed using a medial malleolar osteotomy was 14.32 cm2 (SD = 2.00, range 11.26-16.66). The average quantity of talar exposure expressed as a percentage was 12.94% (SD = 1.79, range 9.97-14.73). The posteromedial approach provided superior visualization of the posterior talus, whereas the medial malleolar osteotomy offered greater access to the medial body. Conclusion: The posteromedial approach and medial malleolar osteotomy allow for significant exposure of the talus, yielding 9.70 and 14.32 cm2, respectively. Given the differing portions of the talus exposed, surgeons may prefer to use the posteromedial approach for operative fixation of posterior process fractures and elect to use a medial malleolar osteotomy in cases requiring more extensive medial and distal exposure for neck or neck/body fractures. Level of Evidence: Level IV.

scholarly journals Confirming putative variants at ≤ 5% allele frequency using allele enrichment and Sanger sequencing

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yan Helen Yan ◽  
Sherry X. Chen ◽  
Lauren Y. Cheng ◽  
Alyssa Y. Rodriguez ◽  
Rui Tang ◽  
...  
Keyword(s):  
Sanger Sequencing ◽  
Limit Of Detection ◽  
High Sensitivity ◽  
Sequencing Errors ◽  
Whole Exome ◽  
Formalin Fixed Paraffin ◽  
Formalin Fixed Paraffin Embedded ◽  
Fresh Frozen ◽  
The Cost ◽  
Allelic Fraction

AbstractWhole exome sequencing (WES) is used to identify mutations in a patient’s tumor DNA that are predictive of tumor behavior, including the likelihood of response or resistance to cancer therapy. WES has a mutation limit of detection (LoD) at variant allele frequencies (VAF) of 5%. Putative mutations called at ≤ 5% VAF are frequently due to sequencing errors, therefore reporting these subclonal mutations incurs risk of significant false positives. Here we performed ~ 1000 × WES on fresh-frozen and formalin-fixed paraffin-embedded (FFPE) tissue biopsy samples from a non-small cell lung cancer patient, and identified 226 putative mutations at between 0.5 and 5% VAF. Each variant was then tested using NuProbe NGSure, to confirm the original WES calls. NGSure utilizes Blocker Displacement Amplification to first enrich the allelic fraction of the mutation and then uses Sanger sequencing to determine mutation identity. Results showed that 52% of the 226 (117) putative variants were disconfirmed, among which 2% (5) putative variants were found to be misidentified in WES. In the 66 cancer-related variants, the disconfirmed rate was 82% (54/66). This data demonstrates Blocker Displacement Amplification allelic enrichment coupled with Sanger sequencing can be used to confirm putative mutations ≤ 5% VAF. By implementing this method, next-generation sequencing can reliably report low-level variants at a high sensitivity, without the cost of high sequencing depth.

Three-dimensional analysis of displacement characteristics of dorsally angulated intra-articular distal radial fractures

2019 ◽  
Vol 45 (4) ◽  
pp. 339-347
Author(s):  
Atsuo Shigi ◽  
Kunihiro Oka ◽  
Kohji Kuriyama ◽  
Hiroyuki Tanaka ◽  
Hideki Yoshikawa ◽  
...  
Keyword(s):  
Dimensional Analysis ◽  
Articular Surface ◽  
Three Dimensional ◽  
Anatomical Reduction ◽  
Distal Radial Fractures ◽  
Level Of Evidence ◽  
Dorsal Wall ◽  
Wall Displacement ◽  
Sigmoid Notch ◽  
Displacement Patterns

Understanding the complex fragmentation of intra-articular distal radial fractures contributes to achieving anatomical reduction during surgery. This study aimed to clarify three-dimensional displacement patterns of intra-articular fragmentation in dorsally angulated, intra-articular distal radial fractures. We identified five characteristic intra-articular fragments: a key fragment, dorsal ulnar corner, dorsal wall, radial column and anterior radial column. The key fragment was displaced with radial deviation, pronation and extension and with dorsal, proximal and radial translations. The dorsal ulnar corner displacement resulted in a gap, a step-off and a deepened concavity for the lunate facet and sigmoid notch. The dorsal wall displacement resulted in a deepened concavity, a gap and a step-off of the dorsal scaphoid facet. The displacements of the radial column and anterior radial column caused a step-off between the scaphoid and lunate facets. The five characteristic intra-articular fragments each created a characteristic gap and step-off in the articular surface. Level of evidence: IV

scholarly journals The Relevant Hormonal Levels and Diagnostic Features of Polycystic Ovary Syndrome in Adolescents

2020 ◽  
Vol 9 (6) ◽  
pp. 1831
Author(s):  
Elena Khashchenko ◽  
Elena Uvarova ◽  
Mikhail Vysokikh ◽  
Tatyana Ivanets ◽  
Lyubov Krechetova ◽  
...  
Keyword(s):  
Logistic Regression ◽  
Polycystic Ovary Syndrome ◽  
Diagnostic Accuracy ◽  
Polycystic Ovary ◽  
Regression Function ◽  
High Sensitivity ◽  
Sex Hormone Binding Globulin ◽  
Control Group ◽  
Ovary Syndrome ◽  
Diagnostic Features

Relevance: The clinical picture of polycystic ovary syndrome (PCOS) is extremely polymorphic, especially in adolescence. At the same time, the diagnostic criteria of PCOS in adolescence are still under discussion, and the hormonal parameters, including anti-Mullerian hormone range and hyperandrogenism, are not determined. The aim of the present study was to characterize the pivotal clinical and hormonal features of PCOS in adolescents and to establish the age-specific thresholds of the most essential hormonal parameters. Design: A case-control study. Methods: The study included 130 girls with PCOS according to the complete Rotterdam criteria, aged 15 to 17 years. The control group consisted of 30 healthy girls with a regular menstrual cycle of the same age. A complete clinical and laboratory examination, hormonal assays, and ultrasound of the pelvic organs were performed. The serums anti-Mullerian hormone (AMH), follicle-stimulating hormone (FSH), luteinizing hormone (LH), LH/FSH, prolactin, estradiol, 17α-OH progesterone (17α-OHP), androstenedione, testosterone (T), dehydroepiandrosterone sulfate (DHEAS), sex hormone-binding globulin (SHBG), leptin, and free androgen index (FAI) were analyzed. The diagnostic accuracy of AMH, FAI, LH/FSH, T, and androstenedione levels in predicting PCOS in adolescents was established using a logistic regression model and calculating area under the receiver operator characteristic (ROC) curve (AUC). Results: The serum levels of LH (9.0 (5.4–13.8) vs. 3.7 (2.5–4.7) IU/L; p < 0.0001), LH/FSH (1.6 (1.0–2.3) vs. 0.7 (0.5–1.1); p < 0.0001), 17α–OHP (4.1 (3.2–5.1) vs. 3.4 (2.7–3.8) nmol/L; p = 0.0071), cortisol (464.0 ± 147.6 vs. 284.0 ± 129.7 nmol/L; p < 0.0001), prolactin (266.0 (175.0–405.0) vs. 189.0 (142.0–269.0) mIU/L; p = 0.0141), T (1.9 (1.2–2.5) vs. 0.8 (0.7–1.1) nmol/L; p < 0.0001), androstenedione (15.8 (11.6–23.2) vs. 8.3 (6.5–10.8) ng/mL; p < 0.0001), AMH (9.5 (7.5–14.9) vs. 5.8 (3.8–6.9) ng/mL; p < 0.0001), FAI (5.5 (2.8–7.0) vs. 1.6 (1.1–2.3); p < 0.0001), SHBG (37.0 (24.7–55.5) vs. 52.9 (39.0–67.6) nmol/L; p = 0.0136), DHEAS (6.8 ± 3.2 vs. 5.1 ± 1.5 μmol/L; p = 0.0039), and leptin (38.7 ± 27.1 vs. 23.7 ± 14.0 ng/mL; p = 0.0178) were significantly altered in the PCOS patients compared to the controls. Multivariate analysis of all studied hormonal and instrumental parameters of PCOS in adolescents revealed as the most essential: AMH level > 7.20 ng/mL, FAI > 2.75, androstenedione > 11.45 ng/mL, total T > 1.15 nmol/L, LH/FSH ratio > 1.23, and the volume of each ovary > 10.70 cm3 (for each criterion sensitivity ≥ 75.0–93.0%, specificity ≥ 83.0–93.0%). The diagnostic accuracy of PCOS determination was 90.2–91.6% with the combined use of either four detected indexes, which was significantly higher than the use of each index separately. The accuracy of PCOS diagnostics reached 92% using AMH and leptin concentrations when the value of the logistic regression function [85.73 − (1.73 × AMH) − (0.12 × Leptin)] was less than 70.72. Conclusions: The results of the study estimate the threshold for AMH, FAI, androstenedione, testosterone, LH/FSH, and ovarian volume, which could be suggested for use in the PCOS diagnostics in adolescents with a high sensitivity and specificity. Moreover, the combination of either four determined indexes improved the diagnostic accuracy for the PCOS detection in adolescents.

scholarly journals Diagnostic Accuracy of the InBios Scrub Typhus Detect™ ELISA for the Detection of IgM Antibodies in Chittagong, Bangladesh

2018 ◽  
Vol 3 (3) ◽  
pp. 95 ◽  
Author(s):  
Stuart Blacksell ◽  
Hugh Kingston ◽  
Ampai Tanganuchitcharnchai ◽  
Meghna Phanichkrivalkosil ◽  
Mosharraf Hossain ◽  
...  
Keyword(s):  
General Population ◽  
Diagnostic Accuracy ◽  
Diagnostic Tests ◽  
Scrub Typhus ◽  
Febrile Illness ◽  
High Sensitivity ◽  
Immunofluorescence Assay ◽  
Immunoglobulin M ◽  
Regional Assessment ◽  
Igm Elisa

Here we estimated the accuracy of the InBios Scrub Typhus Detect™ immunoglobulin M (IgM) ELISA to determine the optimal optical density (OD) cut-off values for the diagnosis of scrub typhus. Patients with undifferentiated febrile illness from Chittagong, Bangladesh, provided samples for reference testing using (i) qPCR using the Orientia spp. 47-kDa htra gene, (ii) IFA ≥1:3200 on admission, (iii) immunofluorescence assay (IFA) ≥1:3200 on admission or 4-fold rise to ≥3200, and (iv) combination of PCR and IFA positivity. For sero-epidemiological purposes (ELISA vs. IFA ≥1:3200 on admission or 4-fold rise to ≥3200), the OD cut-off for admission samples was ≥1.25, resulting in a sensitivity (Sn) of 91.5 (95% confidence interval (95% CI: 96.8–82.5) and a specificity (Sp) of 92.4 (95% CI: 95.0–89.0), while for convalescent samples the OD cut-off was ≥1.50 with Sn of 66.0 (95% CI: 78.5–51.7) and Sp of 96.0 (95% CI: 98.3–92.3). Comparisons against comparator reference tests (ELISA vs. all tests including PCR) indicated the most appropriate cut-off OD to be within the range of 0.75–1.25. For admission samples, the best Sn/Sp compromise was at 1.25 OD (Sn 91.5%, Sp 92.4%) and for convalescent samples at 0.75 OD (Sn 69.8%, Sp 89.5%). A relatively high (stringent) diagnostic cut-off value provides increased diagnostic accuracy with high sensitivity and specificity in the majority of cases, while lowering the cut-off runs the risk of false positivity. This study underlines the need for regional assessment of new diagnostic tests according to the level of endemicity of the disease given the high levels of residual or cross-reacting antibodies in the general population.

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