Triplex us in the diagnosis of asymptomatic deep venous thrombosis

Purpose: to evaluate the accuracy of triplex ultrasound (TUS) compared with venography as a screening test for deep venous thrombosis (DVT), and to evaluate interobserver variation in the interpretation of the venographic studies. Material and Methods: A total of 133 postoperative hip fracture patients, asymptomatic of DVT, were prospectively examined with TUS and venography. All venograms were reviewed blindly and in case of disagreement a consensus was arrived at. Results: the incidence of DVT was 20%, with isolated calf vein thrombi in 63% of the cases. There were 7 false-negative and one false-positive result/s at TUS, with a sensitivity of 74%, specificity of 99% and accuracy of 97%. the kappa values ranged from 0.58 to 0.82. the false-negative results were all caused by missed calf vein thrombi in technically inadequate examinations. at sonography 2% of vein segments were noninterpretable, compared to 29% at venography. Conclusion: Venous US is less sensitive as a test for DVT in this study of asymptomatic patients than in earlier studies on symptomatic patients. Still, sonographic screening of high-risk patients would be both effective and cost effective. Fresh thrombi may cause a false-negative compression test.

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Contact Thermography as a Screening Test for Deep Venous Thrombosis following Major Hip Surgery

Acta Radiologica ◽

10.1177/028418518802900607 ◽

1988 ◽

Vol 29 (6) ◽

pp. 649-652 ◽

Cited By ~ 1

Author(s):

L. Kjær ◽

S. Winter Christensen ◽

Aa. Vestergaard ◽

A. Bjerg-Nielsen ◽

P. Wille-Jørgensen

Keyword(s):

Venous Thrombosis ◽

Deep Venous Thrombosis ◽

No Value ◽

Screening Test ◽

False Negative ◽

Lower Limbs ◽

Hip Surgery ◽

Non Invasive ◽

Negative Results ◽

False Negative Results

Contact thermography is a non-invasive, easily handled, and inexpensive investigation for the diagnosis of deep venous thrombosis (DVT) in the lower limbs. In this study 56 patients with total hip replacement were screened for DVT by contact thermography, using bilateral ascending phlebography as reference procedure. Examinations were performed on the seventh postoperative day. All thermograms were evaluated blindly and independently at the end of the study. Phlebography revealed unilateral DVT in six patients. Only two had corresponding findings at thermography, giving four false negative results. Moreover, 14 false positive thermograms were found. Based on the number of legs investigated, the nosographic sensitivity and specificity thus were 33 and 87 per cent, respectively. It is concluded that contact thermography is of no value as a screening test for DVT following major hip surgery.

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Contact Thermography, 99mTc-Plasmin Scintimetry and 99mTc-Plasmin Scintigraphy as Screening Methods for Deep Venous Thrombosis Following Major Hip Surgery

Thrombosis and Haemostasis ◽

10.1055/s-0038-1645999 ◽

1987 ◽

Vol 58 (03) ◽

pp. 831-833 ◽

Cited By ~ 10

Author(s):

S Winter Christensen ◽

P Wille-Jørgensen ◽

L Kjær ◽

C Stadeager ◽

A Widding ◽

...

Keyword(s):

Venous Thrombosis ◽

Deep Venous Thrombosis ◽

No Value ◽

False Negative ◽

Hip Surgery ◽

Screening Methods ◽

Negative Results ◽

False Negative Results ◽

Screening Procedures ◽

Sensitivity Specificity

SummaryFifty-six patients scheduled for total hip alloplasty were screened for deep venous thrombosis by means of 99mTc-plasmin scintimetry, 99mTc-plasmin scintigraphy and contact thermography. Investigations were performed on the seventh postoperative day, and a total of 112 legs were examined. Bilateral ascending phlebography was used as reference procedure, and the criteria for deep venous thrombosis were intraluminal filling defects at phlebography. Six patients developed unilateral deep venous thrombosis. All three screening procedures revealed many false positive and several false negative results. The nosographic sensitivity/specificity was 33%/75% for scintimetry, 50%/91% for scintigraphy and 33%/87% for contact thermography, respectively. It is concluded that all three tests are of no value as screening methods for deep venous thrombosis following major elective hip surgery.

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Multiplex Target-Redundant RT-LAMP for Robust Detection of SARS-CoV-2 Using Fluorescent Universal Displacement Probes

10.1101/2021.08.13.21261995 ◽

2021 ◽

Author(s):

Enos C Kline ◽

Nuttada Panpradist ◽

Ian T Hull ◽

Qin Wang ◽

Amy K Oreskovic ◽

...

Keyword(s):

Molecular Diagnostics ◽

Detection System ◽

Point Of Care ◽

False Negative ◽

Cost Effective ◽

Internal Amplification Control ◽

Robust Detection ◽

Negative Results ◽

False Negative Results ◽

Target Redundancy

AbstractThe increasing prevalence of variant lineages during the COVID-19 pandemic has the potential to disrupt molecular diagnostics due to mismatches between primers and variant templates. Point-of-care molecular diagnostics, which often lack the complete functionality of their high throughput laboratory counterparts, are particularly susceptible to this type of disruption, which can result in false negative results. To address this challenge, we have developed a robust Loop Mediated Isothermal Amplification assay with single tube multiplexed multi-target redundancy and an internal amplification control. A convenient and cost-effective target specific fluorescence detection system allows amplifications to be grouped by signal using adaptable probes for pooled reporting of SARS-COV-2 target amplifications or differentiation of the Internal Amplification Control. Over the course of the pandemic, primer coverage of viral lineages by the three redundant sub-assays has varied from assay to assay as they have diverged from the Wuhan-Hu-1 isolate sequence, but aggregate coverage has remained high for all variant sequences analyzed, with a minimum of 97.4% (Variant of Interest: Eta). In three instances (Delta, Gamma, Eta), a high frequency mismatch with one of the three sub-assays was observed, but overall coverage remained high due to multi-target redundancy. When challenged with extracted human samples the multiplexed assay showed 100% sensitivity for samples containing greater than 30 copies of viral RNA per reaction, and 100% specificity. These results are further evidence that conventional laboratory methodologies can be leveraged at the point-of-care for robust performance and diagnostic stability over time.

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To Test, Perchance to Diagnose: Practical Strategies for SARS-CoV-2 Testing

Open Forum Infectious Diseases ◽

10.1093/ofid/ofab095 ◽

2021 ◽

Author(s):

Romney M Humphries ◽

Marwan M Azar ◽

Angela M Caliendo ◽

Andrew Chou ◽

Robert C Colgrove ◽

...

Keyword(s):

False Negative ◽

Virus Antigen ◽

Multifaceted Approach ◽

Negative Results ◽

Testing Strategies ◽

Asymptomatic Patients ◽

False Negative Results ◽

Different Populations ◽

Asymptomatic Individuals ◽

Professional Guidelines

Abstract Testing for SARS-CoV-2 in symptomatic and asymptomatic patients is an important component of the multifaceted approach of managing the COVID-19 pandemic. Determining how to best define testing strategies for different populations and incorporating these into broader infection prevention programs can be complex. Many circumstances are not addressed by federal, local or professional guidelines. This commentary describes various scenarios where testing of symptomatic or asymptomatic individuals for SARS-CoV-2 virus (antigen or RNA) can be of potential benefit. Consideration to pre-test probability, risks of testing (impact of false-positive or false-negative results), testing strategy as well as action based on test results are explored. Testing, regardless of setting, must be incorporated into overarching infection control plans which include use of personal protective equipment (e.g., masks), physically distancing, and isolation when exposure is suspected.

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Limited Chest Ultrasound to Replace CXR in Diagnosis of Pneumothorax Post Image-Guided Transthoracic Interventions

Canadian Association of Radiologists Journal ◽

10.1177/08465371211034016 ◽

2021 ◽

pp. 084653712110340

Author(s):

Hooman Hosseini-Nik ◽

Hamid Bayanati ◽

Carolina A. Souza ◽

Ashish Gupta ◽

Matthew D. F. McInnes ◽

...

Keyword(s):

False Positive ◽

False Negative ◽

Chest Ultrasound ◽

Negative Results ◽

Asymptomatic Patients ◽

False Negative Results ◽

Chest X Ray ◽

Grade 3 ◽

Needle Entry ◽

Needle Interventions

Purpose: To assess the diagnostic accuracy of limited chest ultrasound in detecting pneumothorax following percutaneous transthoracic needle interventions using chest X-ray (CXR) as the reference standard. Methods: With IRB approval, after providing consent, asymptomatic patients after percutaneous transthoracic needle interventions were enrolled to undergo limited chest ultrasound in addition to CXR. A chest Radiologist blinded to the patient’s prior imaging performed a bedside ultrasound, scanning only the first 3 anterior intercostal spaces. Pneumothorax diagnosed on CXR was categorized as small or large and on ultrasound as grades 1, 2, or 3 when detected in 1, 2, or 3 intercostal spaces, respectively. Results: 38 patients underwent 36 biopsies (34 lungs, 1 pleura, and 1 mediastinum) and 2 coil localizations. CXR showed pneumothorax in 13 patients. Ultrasound was positive in 10 patients, with 9 true-positives, 1 false-positive, 4 false-negatives, and 24 true-negatives. The false positive results were due to apical subpleural bullae. The false-negative results occurred in 2 small apical and 2 focal pneumothoraces at the needle entry sites. Four pneumothoraces were categorized as large on CXR, all of which were categorized as grade 3 on ultrasound. Sensitivity and specificity of US for detection of pneumothorax of any size were 69.23% (95%CI 38.6%, 90.1%) and 96.0% (95%CI 79.6%, 99.9%), and for detection of large pneumothorax were 100% (95%CI 39.8%, 100%) and 100% (95%CI 89.7%, 100%). Conclusions: Results of this prospective study is promising. Limited chest ultrasound could potentially replace CXR in the management of postpercutaneous transthoracic needle intervention patients.

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IGI-LuNER: single-well multiplexed RT-qPCR test for SARS-CoV-2

10.1101/2020.12.10.20247338 ◽

2020 ◽

Author(s):

Elizabeth C. Stahl ◽

Connor A. Tsuchida ◽

Jennifer R. Hamilton ◽

Enrique Lin-Shiao ◽

Shana L. McDevitt ◽

...

Keyword(s):

False Negative ◽

Cost Effective ◽

Detection Sensitivity ◽

N Gene ◽

Negative Results ◽

False Negative Results ◽

Single Well ◽

Sample Pooling ◽

One Step ◽

Viral Target

AbstractCommonly used RT-qPCR-based SARS-CoV-2 diagnostics require 2-3 separate reactions or rely on detection of a single viral target, adding time and cost or risk of false-negative results. Currently, no test combines detection of widely used SARS-CoV-2 E- and N-gene targets and a sample control in a single, multiplexed reaction. We developed the IGI-LuNER RT-qPCR assay using the Luna Probe Universal One-Step RT-qPCR master mix with publicly available primers and probes to detect SARS-CoV-2 N gene, E gene, and human RNase P (NER). This combined, cost-effective test can be performed in 384-well plates with detection sensitivity suitable for clinical reporting, and will aid in future sample pooling efforts, thus improving throughput of SARS-CoV-2 detection.Graphical Abstract

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68GA-PSMA — LABELED BIOMARKER FOR POSITRON EMISSION TOMOGRAPHY (LITERATURE REVIEW)

Translational Medicine ◽

10.18705/2311-4495-2018-5-5-46-52 ◽

2018 ◽

Vol 5 (5) ◽

pp. 46-52

Author(s):

M. D. Poyda ◽

D. V. Ryzhkova ◽

A. A. Stanzhevsky

Keyword(s):

False Negative ◽

Malignant Neoplasms ◽

Diagnostic Efficiency ◽

Negative Results ◽

Tumor Focus ◽

Positron Emission ◽

False Negative Results ◽

Pet Ct ◽

Risk Patients

The review is devoted to the analysis of the diagnostic efficiency of combined positron emission and computed tomography (PET / CT) with the radiopharmaceutical 68Ga-PSMA in the initial staging of prostate cancer in middle- and high-risk patients, the determination of the tumor focus in the biochemical recurrence of the disease, and monitoring the effectiveness of systemic and radionuclide therapy. The causes of false positive and false negative results of PET / CT are listed and indications for the procedure are presented as well. 68Ga-PSMA diagnostic possibilities as a labeled biomarker of neovascularization in malignant neoplasms of other localizations are briefly described.

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Performance of SARS-CoV-2 antigen testing in symptomatic and asymptomatic adults: a single-center evaluation

BMC Infectious Diseases ◽

10.1186/s12879-021-06716-1 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Stephanie L. Mitchell ◽

Steven Orris ◽

Tanner Freeman ◽

Megan C. Freeman ◽

Michelle Adam ◽

...

Keyword(s):

Symptom Onset ◽

Point Of Care ◽

False Negative ◽

Poor Performance ◽

Nasopharyngeal Swab ◽

Lower Sensitivity ◽

Negative Results ◽

Asymptomatic Patients ◽

False Negative Results ◽

Antigen Testing

Abstract Background Antigen testing offers rapid and inexpensive testing for SARS-CoV-2 but concerns regarding performance, especially sensitivity, remain. Limited data exists for use of antigen testing in asymptomatic patients; thus, performance and reliability of antigen testing remains unclear. Methods 148 symptomatic and 144 asymptomatic adults were included. A nasal swab was collected for testing by Quidel Sofia SARS IFA (Sofia) as point of care. A nasopharyngeal swab was also collected and transported to the laboratory for testing by Cepheid Xpert Xpress SARS-CoV-2/Flu/RSV RT-PCR (Cepheid). Results Overall, Sofia had good agreement with Cepheid (> 95%) in adults, however was less sensitive. Sofia had a sensitivity of 87.8% and 33.3% for symptomatic and asymptomatic patients, respectively. Among symptomatic patients, testing > 5 days post symptom onset resulted in lower sensitivity (82%) when compared with testing within 5 days of symptom onset (90%). Of the four Sofia false-negative results in the asymptomatic cohort, 50% went on to develop COVID-19 disease within 5 days of testing. Specificity in both symptomatic and asymptomatic cohorts was 100%. Conclusions Sofia has acceptable performance in symptomatic adults when tested < 5 days of symptom onset. Caution should be taken when testing patients with ≥ 5 days of symptoms. The combination of low prevalence and reduced sensitivity results in relatively poor performance of in asymptomatic patients. NAAT-based diagnostic assays should be considered in when antigen testing is unreliable, particularly in symptomatic patients with > 5 days of symptom onset and asymptomatic patients.

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The Value of Doppler Ultrasound in Patients with a Clinical Diagnosis of Deep Venous Thrombosis

10.1055/s-0039-1689349 ◽

1975 ◽

Author(s):

J. Meadway ◽

A. N. Nicolaides

Keyword(s):

Venous Thrombosis ◽

Deep Venous Thrombosis ◽

Doppler Ultrasound ◽

False Negative ◽

Clinical Signs ◽

Ultra Sound ◽

Negative Results ◽

Long Saphenous Vein ◽

Before And After ◽

Calf Compression

It has been suggested that Doppler ultrasound examination is useful in the diagnosis of deep venous thrombosis (DVT). The present study was undertaken to compare ultra sound with venography in 120 limbs of 106 patients who presented with clinical DVT or pulmonary embolism. A Parks 801 ultrasonic detector was used over the femoral and popliteal veins with calf compression before and after occlusion of the long saphenous vein at the knee.DVT was confirmed by venography in 44 limbs and was confined to the calf in 10 of these. Ultrasound detected 3 calf thromboses and 29 of 34 more extensive thromboses. The five failures with thrombus proximal to the calf were associated with partial occlusion (1) or extensive collateral circulation (4). Of the 76 limbs normal on venography 21 were thought to have DVT by ultrasound: these false positives could be attributed to oedema (11), haematoma (4), lymphocyst (1), injured muscle (1), cellulitis (1) or excessive tenderness (2) and were unexplained in 1. The results indicate that this test is more accurate than clinical signs alone, but users must be aware of its limitations, particularly the causes of false positive and false negative results.

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