False-negative Results Research Articles

Chromatographic purification technology optimisation of immunoglobulin G (IgG) from horse serum for animal chlamydia diagnostics

The study aimed to develop and evaluate an antibody quality improvement method to improve the accuracy and efficiency of chlamydia diagnosis in horses. The study was conducted in Kazakhstan and included 100 horses of the Kazakh breed infected with chlamydia, which was divided into two groups: experimental and control. In the experimental group, affinity chromatography was used to purify immunoglobulin G (IgG), which allowed for a 95% purity of the antibodies. The control group used a traditional diagnostic method without preliminary purification, which ensured IgG purity of only 60-65%. The data showed that the purified antibodies demonstrated improved diagnostic performance, including an increase in sensitivity of up to 92% and specificity of up to 95%. The purified antibodies provided effective binding to chlamydial antigens even at low concentrations (0.2cμg/ml), which is 2.5 times better than in the control group. The time to obtain a stable diagnostic signal was reduced by 33% and amounted to 20 minutes in the experimental group versus 30 minutes in the control group. The frequency of false-positive results in the experimental group was reduced to 5% and false-negative results to 4%, which significantly increases the overall reliability of diagnostics. The purified antibodies retained their activity for 12 months, demonstrating high stability and durability. These results highlighted the importance of using chromatographic purification to improve the quality of antibodies used for diagnostic purposes and offer a reliable approach for the accurate detection of chlamydia as well as other infectious diseases in animals. The introduction of such methods can significantly improve the efficiency of veterinary diagnostics and contribute to more timely and adequate treatment of animals

Diagnostic performance of fine-needle aspiration in soft tissue tumors: Application of the World Health Organization System for Reporting Soft Tissue Cytopathology and risk of malignancy assessment.

Recently, a new World Health Organization Reporting System for Soft Tissue Cytopathology (WHO System) was introduced. To analyze the value of this system, routine fine-needle aspiration soft tissue tumor (STT) cases were reviewed. Cytology samples of STTs collected between 1954 and 2022 at the Institut Curie were used (2214 cases, including 1376 primary tumors). All specimens were classified according to the predominant cytomorphological pattern and the WHO System. The diagnostic accuracy and risk of malignancy (ROM) in each category were calculated. Final diagnoses revealed 1236 malignancies and 978 benign or low-risk tumors. The original cytological evaluation led to 21 false-negative results (0.85%) and 29 false-positive results (1.17%). Sensitivity, specificity, positive predictive value, and negative predictive value were 98.3%, 92.1%, 97.5%, and 94.2%, respectively. Overall diagnostic accuracy was 94.2%. The ROM calculated according to the WHO System was 29.87%, 2.49%, 39.62%, 51.43%, 68.42%, and 97.69% in the nondiagnostic, benign, atypical, soft tissue neoplasm of uncertain malignant potential, suspicious for malignancy, and malignant categories, respectively; however, it varied broadly depending on the morphological pattern (62.78% in spindle cell tumors, 84.58% in myxoid tumors, 3.00% in lipomatous tumors, 78.15% in epithelioid tumors, 94.26% in pleomorphic tumors, and 100% in round cell tumors). Cytology of STTs is a powerful diagnostic method. Some cytological patterns overlap in different morphological groups, and the possibility of false-negative and false-positive diagnoses may persist. This analysis evidenced utility of the WHO System, especially when combined with morphological pattern assessment. Subclassification in particular diagnostic categories allowed for calculation of the ROM, which is crucial for optimal patient management.

Nitazene test strips: a laboratory evaluation

Background2-Benzylbenzimidazole ‘nitazene’ opioids pose a growing threat to public health. Nitazene analogues are increasingly found mixed with or (mis)sold as heroin and in falsified (non-)opioid medications, posing a great risk of intoxication in users (un)knowingly exposed to these potent opioids. Lateral flow immunoassay nitazene test strips (NTS; BTNX Rapid Response™) became commercially available in Q1 2024, with the aim to enable rapid detection of nitazene analogues in drug samples. As only limited independent data is available on the performance of these strips, this lab-based study aimed at evaluating their potential for drug checking applications.MethodsFollowing dilution of drug standards in water, the NTS readouts were analyzed independently by two individuals and by ImageJ. The limit of detection for isotonitazene was determined using two manufacturing lots of NTS. Cross-reactivity with 32 other nitazene analogues was evaluated. Six sourced drug samples were tested to explore the ability of NTS to detect the presence of a nitazene analogue in authentic samples.ResultsThe limits of detection for isotonitazene were 2000 or 3000 ng/mL, depending on the lot. Twenty-four of the 33 tested nitazene analogues cross-reacted with the NTS at concentrations ≤ 9000 ng/mL. Structural analysis indicated that either substitution or removal of the 5-nitro group, or lengthening the linker between the two aromatic rings, generally hampered detection. All six authentic drug samples consistently tested positive, with no observed false negatives.ConclusionsThis study provides a better understanding of the potential of NTS for drug checking purposes. Our findings indicate that NTS can theoretically alert to the presence of most nitazene analogues that have emerged on recreational drug markets. However, ‘desnitazenes’ (lacking the 5-nitro group) may yield false negative results due to low cross-reactivity. Although factors like specificity, lot-to-lot variability, nitazene analogue content in drug samples, solubility, and different testing conditions should be considered, our study results indicate that, at least under the conditions evaluated here (using reference standards and sourced powders), NTS are capable of detecting the presence of a wide range of nitazene analogues. Hence, NTS may alert users of the presence of nitazene analogues in drug samples.

Development and evaluation of a TaqMan® real-time PCR assay for species-specific detection of Ehrlichia canis

The aim of this work was to develop a real-time PCR assay with a TaqMan® probe that detects a species-specific part of the 16S rDNA gene of Ehrlichia canis. Canine blood samples (n = 207), collected and tested by a conventional PCR assay within a study conducted by De Salvo et al., were simultaneously analyzed with the novel designed real-time PCR, and the results of both assays were compared. The agreement between the two methods was 97.6 % with a kappa value of 0.92186. Hereby, the standard error was 0.034416 and the 95 % confidence interval from 0.8544 to 0.98931. While the conventional PCR assay showed false negative results (2.42 %; 5/207), the real-time PCR assays showed a specificity of 100 %. The results of the current study showed that the developed assay presents sensitivity and specificity for the detection of E. canis in blood samples, adding a new tool for the diagnosis of this pathogen.

Forensic efficiency evaluation of a mtDNA whole genome sequencing system constructed with long fragment amplification strategy on DNA nanoball sequencing platform

Mitochondrial DNA (mtDNA) is an important genetic marker for degraded biological sample identification, maternal pedigree tracing, and population genetic structure study owing to its characteristics of high copy number, anti-degradable ring structure, and maternal inheritance. Whole mtDNA genome sequencing is an optimal method for the analysis of mtDNA polymorphism and heterogeneity because it allows for the comprehensive use of maternal genetic information. However, because of lacking quantitative evaluations for sequencing data, the scientific interpretation standards for mtDNA sequencing results of the previously used sequencing systems are often different, and false positive or false negative results are prone to occur when faced with the interference of nuclear genomic DNA, or the heterogeneities of mtDNA sequence and structure. In this study, we evaluated a novel mtDNA whole genome sequencing system using long fragment amplification strategy on the DNA nanoball (DNB) sequencing platform. This system demonstrated high sequencing quality and specific mtDNA sequencing efficiencies on positive control DNA and FTA bloodstain samples, as the average Q20 and Q30 values of the corresponding samples were 97.17 % and 91.93 %; 97.37 % and 92.48 %, respectively. The mean mapping percentages for the reference sequences of whole genome DNA (wgDNA), mtDNA, and nuclear genomic DNA (ngDNA) in the corresponding samples were 99.98 %, 99.97 %, 0.03 %, and 99.91 %, 99.40 %, 0.60 %; respectively. The average error calling rates for the bases A, C, G, and T of the whole mtDNA genome were 0.2519 %, 0.2550 %, 0.2906 %; and 0.2392 %, respectively. The efficacy of heteroplasmy identification was assessed using a set of theoretical sites with predetermined rates. These sites were created by combining the samples with known mtDNA haplotypes in certain proportions. The absolute errors between observed and theoretical heteroplasmy values were 89.59 %, 74.68 %, 50.20 %, 12.65 %, 8.31 %, and 4.85 %, while the theoretical heteroplasmy values were 5 %, 10 %, 20 %, 80 %, 90 %, and 95 %, respectively. The absolute error exhibited relative stability when the mtDNA sequencing depth exceeded 500×. Furthermore, the system sequencing efficiency was also confirmed among different kinds of samples, and these samples included natural samples (e.g., peripheral blood samples preserved on FTA cards for 2 and 11 years, and on filter paper for 6 and 9 years), degraded samples, sensitivity samples, samples derived from various bodily fluids, and maternal pedigree samples. In summary, the whole mtDNA genome sequencing system used for forensic identification demonstrated high performance in analyzing mtDNA sequence information, and showed significant prospects for forensic application and maternal genetic research.

Autoantibody testing in myositis: an update.

This review aims to provide an update on myositis autoantibody testing strategies. We have focussed on the reliability and usefulness of different myositis autoantibody detection methods, including commonly used solid phase immunoassays and newer discovery techniques. Several studies have highlighted the limitations of currently available immunoassays, particularly when used in populations with low pretest probability and without supporting clinical evidence. While many autoantibodies, such as anti-Jo1, are detected with high sensitivity and specificity, the low incidence of myositis autoantibodies in tested populations reduces their positive predictive value. The low sensitivity of line immunoassays to detect key myositis autoantibodies, including anti-TIF1γ and rarer antisynthetase autoantibodies, is a concern. Myositis autoantibodies are widely accepted as important clinical tools, and hence, there is a significant demand for reliable, accessible, and affordable detection methods. False positives and negative results have the potential to impact on patient care, particularly for malignancy and lung disease associated autoantibodies. Increased availability of myositis autoantibody testing has led to a rise in requests from a broader range of clinicians. It is critically important that clinicians are aware of specific limitations of tests and interpret results in the context of clinical findings.

The Analysis Study of Gender and Risk of Congenital Hypothyroidism : A Comprehensive Systematic Review

Background: Congenital hypothyroidism is defined as a deficiency of thyroid hormone at birth and is one of the most common endocrine disorders in newborns. Congenital hypothyroidism, with a prevalence of 1 in 3000-4000 live births, is the most common preventable cause of mental retardation in children. The aim: The aim of this study to show about gender and risk of congenital hypothyroidism. Methods: By the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) 2020, this study was able to show that it met all of the requirements. Result: Eight publications were found to be directly related to our ongoing systematic examination after a rigorous three-level screening approach. Subsequently, a comprehensive analysis of the complete text was conducted, and additional scrutiny was given to these articles. Conclusion: many risk factors are involved in the development of congenital hypothyroidism in children. It should be noted that the irreversible consequences of this disease for children including mental retardation is one of the cases which to control and remove it. Accordingly, awareness of the birth season could help policymakers who plan preventive programs to reduce the false negative results among neonates, especially girls.

Our Journey from Individual Efforts to Nationwide Support: Implementing Newborn Screening for Spinal Muscular Atrophy in Serbia.

Innovative treatments for spinal muscular atrophy (SMA) yield the utmost advantages only within the presymptomatic phase, underlining the significance of newborn screening (NBS). We aimed to establish statewide NBS for SMA in Serbia. Our stepwise implementation process involved technical validation of a screening assay, collaboration with patient organizations and medical professionals, a feasibility study, and negotiation with public health representatives. Over 12,000 newborns were tested during the 17-month feasibility study, revealing two unrelated SMA infants and one older sibling. All three children received therapeutic interventions during the presymptomatic phase and have shown no signs of SMA. No false-negative results were found among the negative test results. As frontrunners in this field in Serbia, we established screening and diagnostic algorithms and follow-up protocols and raised awareness among stakeholders about the importance of early disease detection, leading to the incorporation of NBS for SMA into the national program on 15 September 2023. Since then, 54,393 newborns have been tested, identifying six SMA cases and enabling timely treatment. Our study demonstrates that effective collaborations between academia, non-profit organizations, and industry are crucial in bringing innovative healthcare initiatives to fruition, and highlights the potential of NBS to revolutionize healthcare outcomes for presymptomatic SMA infants and their families.

Impact of Aphasia on Brain Activation to Motor Commands in Patients with Acute Intracerebral Hemorrhage.

Brain activation to motor commands is seen in 15% of clinically unresponsive patients with acute brain injury. This state called cognitive motor dissociation (CMD) is detectable by electroencephalogram (EEG) or functional magnetic resonance imaging, predicts long-term recovery, and is recommended by recent guidelines to support prognostication. However, false negative CMD results are a particular concern, and occult aphasia in clinically unresponsive patients may be a major factor. This study aimed to quantify the impact of aphasia on CMD testing. We prospectively studied 61 intensive care unit patients admitted with acute primary intracerebral hemorrhage (ICH) who had behavioral evidence of command following or were able to mimic motor commands. All patients underwent an EEG-based motor command paradigm used to detect CMD and comprehensive aphasia assessments. Logistic regression was used to identify predictors of brain activation, including aphasia types and associations with recovery of independence (Glasgow Outcome Scale-Extended score ≥ 4). Of 61 patients, 50 completed aphasia and the EEG-based motor command paradigm. A total of 72% (n = 36) were diagnosed with aphasia. Patients with impaired comprehension (i.e., receptive or global aphasia) were less likely to show brain activation than those with intact comprehension (odds ratio [OR] 0.23 [95% confidence interval 0.05-0.89], p = 0.04). Brain activation was independently associated with Glasgow Outcome Scale-Extended ≥ 4 by 12months (OR 2.4 [95% confidence interval 1.2-5.0], p = 0.01) accounting for the Functional Outcome in Patients with Primary ICH score (OR1.3 [95% confidence interval 1.0-1.8], p = 0.01). Brain activation to motor commands is four times less likely for patients with primary ICH with impaired comprehension. False negative results due to occult receptive aphasia need to be considered when interpreting CMD testing. Early detection of brain activation may help predict long-term recovery in conscious patients with ICH.

Ultrafast Gas Chromatography-Tandem Differential Mobility Spectrometry: Toward A New Generation of On-Site, Real-Time Trace-Explosives Detection.

In the defense and security sector, rapid detection of trace quantities of threat materials is paramount. Traditional instrumentation typically relies on standalone ion mobility techniques due to being inexpensive, portable, and highly sensitive. However, these techniques face limitations when handling complex samples, suffering from low resolving power (often less than 100) and ion-suppression effects, which can lead to false-positive and false-negative results. Here, we present a foundation to the solution through the hyphenation of the flow field thermal gradient gas chromatograph (FF-TG-GC) developed by HyperChrom with a tandem differential ion mobility spectrometer (DMS-DMS) developed in-house at New Mexico State University. The FF-TG-GC demonstrates the ability to separate a variety of nitroaromatic compounds of explosive significance in 20 s using a nitrogen carrier gas, highlighting the potential to offer selectivity advantages without substantially compromising high-throughput demands. These selectivity advantages are illustrated by the successful application of the FF-TG-GC-DMS-DMS to the detection and identification of single-nanogram loadings of 18 explosives and related substances in the presence of interfering materials, such as lactic acid, musk, and diesel. Furthermore, the system is capable of mitigating in-source ion-suppression effects by chromatographic separation of target analytes from background interference prior to ionization.

Subungual melanoma: molecular analysis of 31 cases from early stage to invasive melanoma.

The distinction between the benign subungual melanocytic lesions and an early lesion of subungual melanoma (SUM) remains a diagnostic challenge. We evaluated the routine diagnostic utility of array Comparative Genomic Hybridization (aCGH) to detect whole-genome copy number variations (CNV) as well as targeted next-generation sequencing (NGS) in SUM. This retrospective study included 20 cases of in situ SUM and 11 cases of invasive SUM. Analysis by aCGH detected common oncogene amplifications in all but one case of invasive SUM (n = 10) and in all cases of in situ SUM with a melanocyte count (MC) >45/mm (n = 4 true positive) and the average number of CNV was 8.5. Thirteen remaining cases of in situ SUM gave false negative results (n = 13), owing to a lack of sufficient melanocytes to analyse (median MC of 35.35; range: 10.16-39.5). Molecular analysis failed in four cases (three in situ SUM and one invasive SUM) due to insufficient amounts of DNA. Across the whole cohort, the sensitivity of aCGH was 52%, but when adjusting the cutoff to MC >45/mm, the sensitivity was 93%. Targeted NGS was less informative than aCGH analyses in our series of SUM. To distinguish malignant from benign lesions, especially in situ SUM versus atypical lentiginous melanocytic proliferations, aCGH analysis should be performed when the MC is above 45 melanocytes per linear millimetre. This pangenomic method can detect oncogene amplifications, as well as a number of CNV >3, which strongly support the diagnosis of malignancy.

HPTLC sequentially coupled to UV and SERS: A cost-effective tool for confirmative identification and quantitation of sildenafil in falsified herbal products

The detection of falsified drugs usually requires multi-disciplinary analysis for confirmative identification. Among hyphenated techniques with high specificity detection, thin-layer chromatography coupled with surface-enhanced Raman spectroscopy (TLC-SERS) is an efficient choice, especially for herbal products with diversified matrix. In this study, HPTLC was coupled to two detection techniques: UV absorption and Raman scattering with silver colloid enhancement for the analysis of sildenafil adulterated in herbal products. With this approach, orthogonal UV and SERS spectral data was collected, so that confirmative results could be obtained within a single TLC analysis. How this approach helped to reduce chances of false positive or false negative results was also discussed. The HPTLC sequentially coupled to UV and SERS (HPTLC-UV-SERS) method was developed and validated parallelly on the UV and SERS signals. To improve the repeatability of the SERS signal, several analytical conditions were optimized, so that direct quantitation with TLC-SERS was feasible without chemometric data extrapolation. The determination was done with UV scanning at 304 nm for HPTLC and with SERS signal at 1580 cm−1 (excitation 633 nm). The TLC-SERS method had a detection limit of 1.65 ng/spot, 95 times lower than HPTLC method (157 ng/spot). The HPTLC-UV-SERS method was applied on 24 real herbal samples collected from the market, among which 3 real samples were positive to sildenafil, and quantitation results by UV and SERS were in consistency. Not only this method was proved feasible for practical applications, but the recommendations for TLC-SERS procedures could also be useful in TLC-SERS method development for other compounds.

Quality control for serological testing

ObjectivesThe quality control of serological assays remains controversial. The aim of this project was to describe the problems associated with a working model for controlling these assays and solutions, including using a source of well-defined targets and acceptable limits, a process to identify lot-to-lot reagent variation and an interpretation of the result that accounted for the clinical situation. False-negative results are problematic but can be reduced by identifying and comparing reagent lot variation with previous results. MethodsThe components of the Quality Assurance strategy are the following: Lot-to-lot reagent and calibrator variation assessment; dynamic, big-data approach to determine accurate targets and acceptable limits for manufacturer-provided QC material; negative QC monitoring process; use of commutable EQA with a sufficient method subgroup size to assess bias; clinical assessment of any statistically flagged error; and provision of support to the clinician for the interpretation of results. ResultsThe model described has been used for twelve months, and acceptable variation has been maintained. ConclusionsThe paper presents a solution that emphasizes the early detection of reagent lot variation and patient risk rather than instrument control.Reducing the risk of a false result to patients requires optimal assay quality control and an effective mechanism to support the clinician’s use of these results in diagnosis and monitoring. The problems of serological assays are well-known, but there remain few integrated solutions in the literature.

Detection of soil-transmitted helminths and Schistosoma spp. by nucleic acid amplification test: Results of the first 5 years of the only international external quality assessment scheme.

Infections with soil-transmitted helminths (STH) and schistosomiasis (SCH) result in a significant global health burden, particularly in rural communities in low and middle-income countries. While microscopy remains the primary diagnostic method for STH and SCH in resource-limited settings, nucleic acid amplification tests (NAATs) are gaining prominence as tools for evaluation of public health control programs in endemic countries, and individual diagnosis in high-income countries. Despite the high sensitivity and specificity of NAATs, previous research has highlighted inter-laboratory variations, both in technical and clinical performance, justifying the need for continuous proficiency testing. Results from 5 rounds over a 5-year period of the so far only longitudinal international Helminth External Molecular Quality Assessment Scheme (HEMQAS), coordinated by the Dutch Foundation for Quality Assessment in Medical Laboratories (SKML), were examined in order to (i) assess the diagnostic proficiency of laboratories in detecting helminths in stool and (ii) identify potential factors contributing to variations in performance. Thirty-six laboratories, from 18 countries and 5 continents, participated in HEMQAS. The overall diagnostic performances were satisfying, with remarkably low numbers (<2%) of false-positive results. False-negative results were more often reported for stool (15%) than for DNA (5%) samples. False-negative results varied largely between targets (the highest number (29%) for Trichuris trichiura). Twenty-five laboratories provided a sufficient number of results for a robust comparison between participating laboratories, which confirmed substantial inter-laboratory variability in quantitative NAAT results (Cq-values). This variability likely arises from differences in pre-treatment, DNA isolation and DNA-target amplification procedures. This study emphasizes the complexity of molecular diagnosis for STH and SCH, highlighting the critical role of proper stool preparation and DNA isolation methods. The results underscore the necessity for laboratory professionals and public health decision-makers to recognize these complexities and continuously undertake external quality assessment schemes to ensure accurate and reliable performance in molecular diagnosis.

Deep Machine Learning for Automatic Segmentation of the Pancreatic Parenchyma and its hypo- and hypervascular lesions on CT Images

Objective of the study. To develop and evaluate the effectiveness of a technology for segmenting the pancreatic parenchyma and its hyper- and hypovascular lesions on abdominal computed tomography (CT) scans using deep machine learning.Materials and methods. CT scans from the database of the A.V. Vishnevsky National Medical Research Center of Surgery were used for training and testing the algorithms – a total number of approximately 150 studies (arterial and venous phases). A test dataset of 46 anonymized CT scans (arterial and venous phases) was prepared for validation of the obtained algorithms, independently assessed by expert physicians. The primary segmentation neural network used is nn-UNet (M. Antonelli et al., 2022).Results. The average accuracy of the test dataset for the model determining segmentation masks of the pancreas on CT images had an AUC of 0.8 for the venous phase and 0.85 for the arterial phase. The segmentation masks of pancreatic formations had an AUC of 0.6.Conclusion. Automated segmentation of the pancreatic parenchyma structure using deep machine learning technologies demonstrated high accuracy. However, the segmentation of hypo- and hypervascular pancreatic lesions requires improvement. The overlap of the masks showed a rather low result, but in all cases, the location of the pathological formation was correctly identified by the algorithm. Enhancing the training dataset and the algorithm used could increase the accuracy of the algorithm.No false negative results were obtained when detecting pancreatic formations; in all cases, the INS detected “suspicious” areas of the pancreatic parenchyma. This can help reduce the omission of pancreatic pathologies in CT scans, and their further assessment can be carried out by the radiologist himself.

The Investigation of the Effect of Electrolyte Disorder on Sweat Test in Newborns with Positive Cystic Fibrosis Screening

Background and objectives: The aim of this study is to investigate the effect of the electrolyte and acid-base status present at the time of admission to the hospital on the sweat test (ST) of the patients who were found to have a positive newborn screening test (NST) for Cystic Fibrosis (CF). Methods: The patients who referred to pediatric pulmonology clinic for ST with positive NST for CF and diagnosed as CF were analyzed retrospectively. From the medical records acid-base status measured simultaneously with the ST and with serum sodium, potassium, and chloride levels were included in the study. Results: The study completed with 37 patients who met the inclusion criteria. At the time of ST, the mean sodium, potassium and chlorine values were 134.83±4.25 (122.0-141.0), 4.94±0.95 (2.9-7.6) and 97.72±12.40 (64.0-116.0) mEq/L, respectively. Patients whose electrolytes were measured at the time of diagnosis, 27.0% (n=10) had hyponatremia, 8.1% (n=3) had hypokalemia, and 4.8% (n=1) had hypochloremia. There was a significant difference between serum chloride and bicarbonate levels according to the negative, borderline, positive ST groups (p=0,036). In addition, no significance detected between the sweat test values of patients with Pseudo-Bartter Syndrome (PBS) (38.7%) and without. Conclusion: The chloride level during ST is lower in patients with borderline and negative ST results. The mean potassium and chloride values of the patients with PBS are lower while the mean bicarbonate value is higher. This may cause false negative results in ST. So, it is important to check the serum electrolyte levels before the ST is performed in the newborn screening positive baby.

The use of vacuum fine needle aspiration biopsy of small formations in the diagnosis of thyroid cancer

Introduction. Diagnosis and treatment of lesional pathology of the thyroid are important problems in Russia and worldwide. Currently, fine-needle aspiration (FNA) is the main technique of differential diagnosis of benign and malignant tumors of the thyroid. In 2023, clinical guidelines of the European Thyroid Association (ETA) on thyroid lesion treatment were published noting possible minimally invasive treatment of benign and malignant tumors of the thyroid requiring repeat cytologic verification. Despite the proven effectiveness of FNA, its informativity and specificity vary between 60 and 100 %. Additionally, this method is associated with high risk of false negative and false positive results. Therefore, there is a need to improve FNA and minimize its disadvantages.Aim. To evaluate the capabilities of vacuum FNA of small lesions using multiparameter ultrasound in diagnosis of thyroid cancer.Materials and methods. At the scientific and practical problem laboratory Diagnostic Studies and Minimally Invasive Technologies of the Smolensk State Medical University, a device for vacuum FNA was developed. Between 2023 and 2024, patients with thyroid lesions of size &lt;10 mm underwent 25 vacuum FNAs. Correlation analysis with 51 FNAs performed between 2020 and 2023 was performed.Results. A decrease in the number of nondiagnostic (category I per the Bethesda system, 2017) and undetermined (category III per the Bethesda system, 2017) results was observed. Comparison of preoperative cytologic conclusions (category V per the Bethesda system, 2017) with the results of postoperative histological examination in patients of the control group showed benign lesions in 2 (50 %) cases which correspond to false negative results. Vacuum FNA did not show this discrepancy. These results demonstrate a decrease in the probability of false negative results and effectiveness of vacuum FNA.Conclusion. Use of vacuum FNA expedites ultrasound-guided biopsy for small thyroid lesions. Due to high negative pressure (up to –0.8 bar), single-step retrieval of cytologic material is performed which leads to a decrease in the number of nondiagnostic and undetermined cytologic conclusions by 11.7 and 1.9 %, respectively.

Matrix effects in ultra-high performance supercritical fluid chromatography-mass spectrometry analysis of vitamin E in plasma: The effect of sample preparation and data processing

The approaches to matrix effects determination and reduction in ultra-high performance supercritical fluid chromatography with mass spectrometry detection have been evaluated in this study using different sample preparation methods and investigation of different calibration models. Five sample preparation methods, including protein precipitation, liquid-liquid extraction, supported liquid extraction, and solid phase extraction based on both “bind and elute” and “interferent removal” modes, were optimized with an emphasis on the matrix effects and recovery of 8 forms of vitamin E, including α-, β-, γ-, and δ-tocopherols and tocotrienols, from plasma. The matrix effect evaluation included the use and comparison of external and internal calibration using three models, i.e., least square with no transformation and no weighting (1/x0), with 1/x2 weighting, and with logarithmic transformation. The calibration model with logarithmic transformation provided the lowest %-errors and the best fits. Moreover, the type of the calibration model significantly affected not only the fit of the data but also the matrix effects when evaluating them based on the comparison of calibration curve slopes. Indeed, based on the used calibration model, the matrix effects calculated from calibration slopes ranged from +92% to – 72% for α-tocopherol and from −77% to +19% in the case of δ-tocotrienol. Thus, it was crucial to calculate the matrix effect by Matuszewski's post-extraction approach at six concentration levels. Indeed, a strong concentration dependence was observed for all optimized sample preparation methods, even if the stable isotopically labelled internal standards (SIL-IS) were used for compensation. The significant differences between individual concentration levels and compounds were observed, even when the tested calibration range covered only one order of magnitude. In methods with wider calibration ranges, the inappropriate use of calibration slope comparison instead of the post-extraction addition approach could result in false negative results of matrix effects. In the selected example of vitamin E, solid-phase extraction was the least affected by matrix effects when used in interferent removal mode, but supported liquid extraction resulted in the highest recoveries. We showed that the calibration model, the use of a SIL-IS, and the analyte concentration level played a crucial role in the matrix effects. Moreover, the matrix effects can significantly differ for compounds with similar physicochemical properties and close retention times. Thus, in all bioanalytical applications, where different analytes are typically determined in one analytical run, it is necessary to carefully select the data processing in addition to the method for the sample preparation, SIL-IS, and chromatography.

Screening Strategies and Methodologies.

While glaucoma is a leading cause of irreversible vision loss, it presents technical challenges in the design and implementation of screening. New technologies such as PRS and AI offer potential improvements in our ability to identify people at high risk of sight loss from glaucoma and may improve the viability of screening for this important disease. To review the current evidence and concepts around screening for glaucoma. A group of glaucoma-focused clinician scientists drew on knowledge and experience around glaucoma, its etiology, and the options for screening. Glaucoma is a chronic progressive optic neuropathy affecting around 76 million individuals worldwide and is the leading cause of irreversible blindness globally. Early stages of the disease are asymptomatic meaning a substantial proportion of cases remain undiagnosed. Early detection and timely intervention reduce the risk of glaucoma-related visual morbidity. However, imperfect tests and a relatively low prevalence currently limit the viability of population-based screening approaches. The diagnostic yield of opportunistic screening strategies, relying on the identification of disease during unrelated health care encounters, such as cataract clinics and diabetic retinopathy screening programs, focusing on older people and/or those with a family history, are hindered by a large number of false-positive and false-negative results. Polygenic risk scores (PRS) offer personalized risk assessment for adult-onset glaucoma. In addition, artificial intelligence (AI) algorithms have shown impressive performance, comparable to expert humans, in discriminating between potentially glaucomatous and non-glaucomatous eyes. These emerging technologies may offer a meaningful improvement in diagnostic yield in glaucoma screening. While glaucoma is a leading cause of irreversible vision loss, it presents technical challenges in the design and implementation of screening. New technologies such as PRS and AI offer potential improvements in our ability to identify people at high risk of sight loss from glaucoma and may improve the viability of screening for this important disease.

Improved Detection of Small and Low-Density Plaques in Virtual Noncontrast Imaging-based Calcium Scoring at Photon-Counting Detector CT.

Purpose To investigate the impact of plaque size and density on virtual noncontrast (VNC)-based coronary artery calcium scoring (CACS) using photon-counting detector CT and to provide safety net reconstructions for improved detection of subtle plaques in patients whose VNC-based CACS would otherwise be erroneously zero when compared with true noncontrast (TNC)-based CACS. Materials and Methods In this prospective study, CACS was evaluated in a phantom containing calcifications with different diameters (5, 3, and 1 mm) and densities (800, 400, and 200 mg/cm3) and in participants who underwent TNC and contrast-enhanced cardiac photon-counting detector CT (July 2021-March 2022). VNC images were reconstructed at different virtual monoenergetic imaging (55-80 keV) and quantum iterative reconstruction (QIR) levels (QIR,1-4). TNC scans at 70 keV with QIR off served as the reference standard. In vitro CACS was analyzed using standard settings (3.0-mm sections, kernel Qr36, 130-HU threshold). Calcification detectability and CACS of small and low-density plaques were also evaluated using 1.0-mm sections, kernel Qr44, and 120- or 110-HU thresholds. Safety net reconstructions were defined based on background Agatston scores and evaluated in vivo in TNC plaques initially nondetectable using standard VNC reconstructions. Results The in vivo cohort included 63 participants (57.8 years ± 15.5 [SD]; 37 [59%] male, 26 [41%] female). Correlation and agreement between standard CACSVNC and CACSTNC were higher in large- and medium-sized and high- and medium-density than in low-density plaques (in vitro: intraclass correlation coefficient [ICC] ≥ 0.90; r > 0.9 vs ICC = 0.20-0.48; r = 0.5-0.6). Small plaques were not detectable using standard VNC reconstructions. Calcification detectability was highest using 1.0-mm sections, kernel Qr44, 120- and 110-HU thresholds, and QIR level of 2 or less VNC reconstructions. Compared with standard VNC, using safety net reconstructions (55 keV, QIR 2, 110-HU threshold) for in vivo subtle plaque detection led to higher detection (increased by 89% [50 of 56]) and improved correlation and agreement of CACSVNC with CACSTNC (in vivo: ICC = 0.51-0.61; r = 0.6). Conclusion Compared with TNC-based calcium scoring, VNC-based calcium scoring was limited for small and low-density plaques but improved using safety net reconstructions, which may be particularly useful in patients with low calcium scores who would otherwise be treated based on potentially false-negative results. Keywords: Coronary Artery Calcium CT, Photon-Counting Detector CT, Virtual Noncontrast, Plaque Size, Plaque Density Supplemental material is available for this article. © RSNA, 2024.