Comparative Analysis of Droplet-Based Ultra-High-Throughput Single-Cell RNA-Seq Systems.

Since its establishment in 2009, single-cell RNA sequencing (RNA-seq) has been a major driver behind progress in biomedical research. In developmental biology and stem cell studies, the ability to profile single cells confers particular benefits. Although most studies still focus on individual tissues or organs, the recent development of ultra-high-throughput single-cell RNA-seq has demonstrated potential power in characterizing more complex systems or even the entire body. However, although multiple ultra-high-throughput single-cell RNA-seq systems have attracted attention, no systematic comparison of these systems has been performed. Here, with the same cell line and bioinformatics pipeline, we developed directly comparable datasets for each of three widely used droplet-based ultra-high-throughput single-cell RNA-seq systems, inDrop, Drop-seq, and 10X Genomics Chromium. Although each system is capable of profiling single-cell transcriptomes, their detailed comparison revealed the distinguishing features and suitable applications for each system.

Precision oncology: a review to assess interpretability in several explainable methods.

Great efforts have been made to develop precision medicine-based treatments using machine learning. In this field, where the goal is to provide the optimal treatment for each patient based on his/her medical history and genomic characteristics, it is not sufficient to make excellent predictions. The challenge is to understand and trust the model's decisions while also being able to easily implement it. However, one of the issues with machine learning algorithms-particularly deep learning-is their lack of interpretability. This review compares six different machine learning methods to provide guidance for defining interpretability by focusing on accuracy, multi-omics capability, explainability and implementability. Our selection of algorithms includes tree-, regression- and kernel-based methods, which we selected for their ease of interpretation for the clinician. We also included two novel explainable methods in the comparison. No significant differences in accuracy were observed when comparing the methods, but an improvement was observed when using gene expression instead of mutational status as input for these methods. We concentrated on the current intriguing challenge: model comprehension and ease of use. Our comparison suggests that the tree-based methods are the most interpretable of those tested.

Comparative Analysis of Single-Cell RNA Sequencing Methods.

Single-cell RNA sequencing (scRNA-seq) offers new possibilities to address biological and medical questions. However, systematic comparisons of the performance of diverse scRNA-seq protocols are lacking. We generated data from 583 mouse embryonic stem cells to evaluate six prominent scRNA-seq methods: CEL-seq2, Drop-seq, MARS-seq, SCRB-seq, Smart-seq, and Smart-seq2. While Smart-seq2 detected the most genes per cell and across cells, CEL-seq2, Drop-seq, MARS-seq, and SCRB-seq quantified mRNA levels with less amplification noise due to the use of unique molecular identifiers (UMIs). Power simulations at different sequencing depths showed that Drop-seq is more cost-efficient for transcriptome quantification of large numbers of cells, while MARS-seq, SCRB-seq, and Smart-seq2 are more efficient when analyzing fewer cells. Our quantitative comparison offers the basis for an informed choice among six prominent scRNA-seq methods, and it provides a framework for benchmarking further improvements of scRNA-seq protocols.

Comparison of colorimetric, fluorometric, and liquid chromatography-mass spectrometry assays for acetyl-coenzyme A.

Acetyl-Coenzyme A is a central metabolite in catabolic and anabolic pathways as well as the acyl donor for acetylation reactions. Multiple quantitative measurement techniques for acetyl-CoA have been reported, including commercially available kits. Comparisons between techniques for acetyl-CoA measurement have not been reported. This lack of comparability between assays makes context-specific assay selection and interpretation of results reporting changes in acetyl-CoA metabolism difficult. We compared commercially available colorimetric ELISA and fluorometric enzymatic-based kits to liquid chromatography-mass spectrometry-based assays using tandem mass spectrometry (LC-MS/MS) and high-resolution mass spectrometry (LC-HRMS). The colorimetric ELISA kit did not produce interpretable results even with commercially available pure standards. The fluorometric enzymatic kit produced comparable results to the LC-MS-based assays depending on matrix and extraction. LC-MS/MS and LC-HRMS assays produced well-aligned results, especially when incorporating stable isotope-labeled internal standards. In addition, we demonstrated the multiplexing capability of the LC-HRMS assay by measuring a suite of short-chain acyl-CoAs in a variety of acute myeloid leukemia cell lines and patient cells.

Evaluation of effects from hemoglobin variants on HbA1c measurements by different methods.

OBJECTIVES: The impact of seven hemoglobin variants (Hb Q-Thailand, Hb G-Honolulu, Hb Ube-2, Hb New York, Hb J-Bangkok, Hb G-Coushatta, and Hb E) on the outcome of HbA1c was investigated for six methods by comparing with liquid chromatography-tandem mass spectrometry (LC/MS/MS) reference method. METHODS: Twenty-nine normal and 112 variant samples were measured by LC/MS/MS, Sebia Capillarys 3 TERA, Intelligene Biosystems QuanTOF, Premier Hb9210, Arkray HA-8190V, Bio-Rad D-100, and Tosoh G11, then evaluated for correlation, consistency, and mean relative bias among six methods. The lowest biological variation bias of ±2.8 % was an acceptable standard. RESULTS: All methods showed poor correlation and consistency with LC/MS/MS for Hb E. The unacceptable biases were observed for Capillarys 3 TERA (-14.4 to -3.7 % for Hb Q-Thailand, Hb Ube-2, Hb New York, Hb J-Bangkok and Hb E), QuanTOF (-8.3 to -2.9 % for Hb Ube-2, Hb New York and Hb G-Coushatta), Premier Hb9210 (-18.3 to -3.6 % for Hb Q-Thailand, Hb Ube-2, Hb New York, Hb J-Bangkok and Hb E), HA-8190V variant mode (-17.3 to 6.6 % for Hb G-Honolulu, Hb Ube-2, Hb New York, Hb G-Coushatta and Hb E). All variant samples showed larger biases than ±2.8 % comparing HA-8190V fast mode, D-100, and G11 with LC/MS/MS. CONCLUSIONS: The accuracy of different HbA1c methods was influenced by some Hb variants, especially Hb Ube-2 and Hb New York. Thus, laboratories need to choose appropriate methods to measure HbA1c with different Hb variants.

Evaluation of five multisteroid LC‒MS/MS methods used for routine clinical analysis: comparable performance was obtained for nine analytes.

OBJECTIVES: A mass spectrometry (LC‒MS/MS)-based interlaboratory comparison study was performed for nine steroid analytes with five participating laboratories. The sample set contained 40 pooled samples of human serum generated from preanalyzed leftovers. To obtain a well-balanced distribution across reference intervals of each steroid, the leftovers first underwent a targeted mixing step. METHODS: All participants measured a sample set once using their own multianalyte protocols and calibrators. Four participants used in-house developed measurement platforms, including IVD-CE certified calibrators, which were used by three participants; the 5th lab used the whole LC‒MS kit from an IVD manufacturer. All labs reported results for 17-hydroxyprogesterone, androstenedione, cortisol, and testosterone, and four labs reported results for 11-deoxycortisol, corticosterone, cortisone, dehydroepiandrosterone sulfate (DHEAS), and progesterone. RESULTS: Good or acceptable overall comparability was found in Bland‒Altman and Passing‒Bablok analyses. Mean bias against the overall mean remained less than ±10 % except for DHEAS, androstenedione, and progesterone at one site and for cortisol and corticosterone at two sites (max. -18.9 % for androstenedione). The main analytical problems unraveled by this study included a bias not previously identified in proficiency testing, operator errors, non-supported matrix types and higher inaccuracy and imprecision at lower ends of measuring intervals. CONCLUSIONS: This study shows that intermethod comparison is essential for monitoring the validity of an assay and should serve as an example of how external quality assessment could work in addition to organized proficiency testing schemes.

Clinical specificity of two assays for immunoglobulin kappa and lambda free light chains.

OBJECTIVES: Free light chain (FLC) assays and the ratio of κ/λ are recommended for diagnosis, prognosis and monitoring of plasma cell dyscrasias (PCD). Limited data exists on FLC clinical specificity in patients diagnosed with other conditions. METHODS: We assessed the κ, λ, and κ/λ FLC ratio using the FreeLite assay and the Sebia FLC ELISA assay in 176 patients with clinical presentations of fatigue, anemia, polyclonal hypergammaglobulinemia, joint disorders, kidney disease and non PCD-cancers with no monoclonal protein observed on serum protein electrophoresis or MASS-FIX immunoglobulin isotyping. Manufacturer defined reference intervals (RI) and glomerular filtration rate (GFR) specific RI (renal RI) were utilized. RESULTS: For the κ/λ ratio, 68.7 % (121/176) of specimens on the FreeLite and 87.5 % (154/176) of specimens on the Sebia assay were within RI. For κ, 68.2 % (120/176) and 72.2 % (127/176) of results were outside RI for FreeLite and Sebia respectively. For λ, 37.5 % (66/176) and 84.1 % (148/176) of FreeLite and Sebia results were outside RI. With FreeLite and Sebia, patients with kidney disease (n=25) had the highest κ/λ ratios. 44 patients (25.0 %) had GFR <60 mL/min/BSA. When renal RI were applied, 13.6 % had a FLCr outside the renal RI with FreeLite, and 4.5 % with Sebia. CONCLUSIONS: In a cohort of patients with signs and symptoms suggestive of PCDs, but ultimately diagnosed with other conditions, Sebia FLC had improved clinical specificity relative to FreeLite, if one was using an abnormal κ/λ ratio as a surrogate for monoclonality.

Mouse Model of Fragile X Syndrome Analyzed by Quantitative Proteomics: A Comparison of Methods.

Multiple methods for quantitative proteomics are available for proteome profiling. It is unclear which methods are most useful in situations involving deep proteome profiling and the detection of subtle distortions in the proteome. Here, we compared the performance of seven different strategies in the analysis of a mouse model of Fragile X Syndrome, involving the knockout of the fmr1 gene that is the leading cause of autism spectrum disorder. Focusing on the cerebellum, we show that data-independent acquisition (DIA) and the tandem mass tag (TMT)-based real-time search method (RTS) generated the most informative profiles, generating 334 and 329 significantly altered proteins, respectively, although the latter still suffered from ratio compression. Label-free methods such as BoxCar and a conventional data-dependent acquisition were too noisy to generate a reliable profile, while TMT methods that do not invoke RTS showed a suppressed dynamic range. The TMT method using the TMTpro reagents together with complementary ion quantification (ProC) overcomes ratio compression, but current limitations in ion detection reduce sensitivity. Overall, both DIA and RTS uncovered known regulators of the syndrome and detected alterations in calcium signaling pathways that are consistent with calcium deregulation recently observed in imaging studies. Data are available via ProteomeXchange with the identifier PXD039885.

Within-Person and Between-Sensor Variability in Continuous Glucose Monitoring Metrics.

BACKGROUND: The within-person and between-sensor variability of metrics from different interstitial continuous glucose monitoring (CGM) sensors in adults with type 2 diabetes not taking insulin is unclear. METHODS: Secondary analysis of data from 172 participants from the Hyperglycemic Profiles in Obstructive Sleep Apnea randomized clinical trial. Participants simultaneously wore Dexcom G4 and Abbott Libre Pro CGM sensors for up to 2 weeks at baseline and again at the 3-month follow-up visit. RESULTS: At baseline (up to 2 weeks of CGM), mean glucose for both the Abbott and Dexcom sensors was approximately 150 mg/dL (8.3 mmol/L) and time in range (70180 mg/dL [3.910.0 mmol/L]) was just below 80. When comparing the same sensor at 2 different time points (two 2-week periods, 3 months apart), the within-person coefficient of variation (CVw) in mean glucose was 17.4 (Abbott) and 14.2 (Dexcom). CVw for percent time in range: 20.1 (Abbott) and 18.6 (Dexcom). At baseline, the Pearson correlation of mean glucose from the 2 sensors worn simultaneously was r 0.86, root mean squared error (RMSE), 13 mg/dL (0.7 mmol/L); for time in range, r 0.88, RMSE, 8 percentage points. CONCLUSIONS: Substantial variation was observed within sensors over time and across 2 different sensors worn simultaneously on the same individuals. Clinicians should be aware of this variability when using CGM technology to make clinical decisions.ClinicalTrials.gov Identifier: NCT02454153.

Tracing plant source water dynamics during drought by continuous transpiration measurements: An in-situ stable isotope approach.

The isotopic composition of xylem water (δX ) is of considerable interest for plant source water studies. In-situ monitored isotopic composition of transpired water (δT ) could provide a nondestructive proxy for δX -values. Using flow-through leaf chambers, we monitored 2-hourly δT -dynamics in two tropical plant species, one canopy-forming tree and one understory herbaceous species. In an enclosed rainforest (Biosphere 2), we observed δT -dynamics in response to an experimental severe drought, followed by a 2 H deep-water pulse applied belowground before starting regular rain. We also sampled branches to obtain δX -values from cryogenic vacuum extraction (CVE). Daily flux-weighted δ18 OT -values were a good proxy for δ18 OX -values under well-watered and drought conditions that matched the rainforest's water source. Transpiration-derived δ18 OX -values were mostly lower than CVE-derived values. Transpiration-derived δ2 HX -values were relatively high compared to source water and consistently higher than CVE-derived values during drought. Tracing the 2 H deep-water pulse in real-time showed distinct water uptake and transport responses: a fast and strong contribution of deep water to canopy tree transpiration contrasting with a slow and limited contribution to understory species transpiration. Thus, the in-situ transpiration method is a promising tool to capture rapid dynamics in plant water uptake and use by both woody and nonwoody species.

The Preventiometer - reliability of a cardiovascular multi-device measurement platform and its measurement agreement with a cohort study.

BACKGROUND: Multimedia multi-device measurement platforms may make the assessment of prevention-related medical variables with a focus on cardiovascular outcomes more attractive and time-efficient. The aim of the studies was to evaluate the reliability (Study 1) and the measurement agreement with a cohort study (Study 2) of selected measures of such a device, the Preventiometer. METHODS: In Study 1 (N = 75), we conducted repeated measurements in two Preventiometers for four examinations (blood pressure measurement, pulse oximetry, body fat measurement, and spirometry) to analyze their agreement and derive (retest-)reliability estimates. In Study 2 (N = 150), we compared somatometry, blood pressure, pulse oximetry, body fat, and spirometry measurements in the Preventiometer with corresponding measurements used in the population-based Study of Health in Pomerania (SHIP) to evaluate measurement agreement. RESULTS: Intraclass correlations coefficients (ICCs) ranged from .84 to .99 for all examinations in Study 1. Whereas bias was not an issue for most examinations in Study 2, limits of agreement for most examinations were very large compared to results of similar method comparison studies. CONCLUSION: We observed a high retest-reliability of the assessed clinical examinations in the Preventiometer. Some disagreements between Preventiometer and SHIP examinations can be attributed to procedural differences in the examinations. Methodological and technical improvements are recommended before using the Preventiometer in population-based research.

Albumin determined by bromocresol green leads to erroneous results in routine evaluation of patients with chronic kidney disease.

OBJECTIVES: Measurement of plasma albumin is pivotal for clinical decision-making in patients with chronic kidney disease (CKD). Routinely used methods as bromocresol green (BCG) and bromocresol purple (BCP) can suffer from aselectivity, but the impact of aselectivity on the accuracy of plasma albumin results of CKD-patients is still unknown. Therefore, we evaluated the performance of BCG-, BCP- and JCTLM-endorsed immunological methods in patients with various stages of CKD. METHODS: We evaluated the performance of commonly used albumin methods in patients with CKD stages G1 through G5, the latter divided in two groups based on whether they received hemodialysis treatment. In total, 163 patient plasma samples were measured at 14 laboratories, on six different BCG and BCP-platforms, and four different immunological platforms. The results were compared with an ERM-DA-470k-corrected nephelometric assay. The implications on outcome is evaluated by the proportion of patient results <38 g/L for the diagnosis of protein energy wasting. RESULTS: Albumin results determined with BCP- and immunological methods showed the best agreement with the target value (92.7 and 86.2 %, respectively vs. 66.7 % for BCG, namely due to overestimation). The relative agreement of each method with the target value was platform-dependent, with larger variability in agreement between platforms noted for BCG and immunological methods (3.2-4.6 and 2.6-5.3 %) as opposed to BCP (0.7-1.5 %). The stage of CKD had similar effects on the variability in agreement for the three method-groups (0.6-1.8 % vs. 0.7-1.5 % vs. 0.4-1.6 %). The differences between methods cause discrepancies in clinical decision-making, as structurally fewer patients were diagnosed with protein energy wasting upon using BCG-based albumin results. CONCLUSIONS: Our study shows that BCP is fit for the intended use to measure plasma albumin levels in CKD patients from all stages, including patients on hemodialysis. In contrast, most BCG-based platforms falsely overestimate the plasma albumin concentration.

Salivary cortisol and cortisone in diagnosis of Cushing's syndrome - a comparison of six different analytical methods.

OBJECTIVES: Salivary cortisol and cortisone at late night and after dexamethasone suppression test (DST) are increasingly used for screening of Cushing's syndrome (CS). We aimed to establish reference intervals for salivary cortisol and cortisone with three liquid chromatography-tandem mass spectrometry (LC-MS/MS) techniques and for salivary cortisol with three immunoassays (IAs), and evaluate their diagnostic accuracy for CS. METHODS: Salivary samples at 08:00 h, 23:00 h and 08:00 h after a 1-mg DST were collected from a reference population (n=155) and patients with CS (n=22). Sample aliquots were analyzed by three LC-MS/MS and three IA methods. After establishing reference intervals, the upper reference limit (URL) for each method was used to calculate sensitivity and specificity for CS. Diagnostic accuracy was evaluated by comparing ROC curves. RESULTS: URLs for salivary cortisol at 23:00 h were similar for the LC-MS/MS methods (3.4-3.9 nmol/L), but varied between IAs: Roche (5.8 nmol/L), Salimetrics (4.3 nmol/L), Cisbio (21.6 nmol/L). Corresponding URLs after DST were 0.7-1.0, and 2.4, 4.0 and 5.4 nmol/L, respectively. Salivary cortisone URLs were 13.5-16.6 nmol/L at 23:00 h and 3.0-3.5 nmol/L at 08:00 h after DST. All methods had ROC AUCs ≥0.96. CONCLUSIONS: We present robust reference intervals for salivary cortisol and cortisone at 08:00 h, 23:00 h and 08:00 h after DST for several clinically used methods. The similarities between LC-MS/MS methods allows for direct comparison of absolute values. Diagnostic accuracy for CS was high for all salivary cortisol and cortisone LC-MS/MS methods and salivary cortisol IAs evaluated.

Poor comparability of plasma renin activity measurement in determining patient samples: the status quo and recommendations for harmonization.

OBJECTIVES: This study aims to investigate and update the consistency and comparability of plasma renin activity (PRA) assays in measuring clinical samples. The contributions of recalibration, blank subtraction, and incubation strategies to interchangeability were also explored. METHODS: Five different laboratories were evaluated using forty-six individual plasma samples, including four liquid chromatography-tandem mass spectrometry (LC‒MS/MS) assays and one chemiluminescence immunoassay (CLIA). Spearman correlation coefficient (R), Passing-Bablok regression, and Bland‒Altman plot analyses were used to evaluate the consistency among assays. Consistency before and after recalibration, blank subtraction, and incubation strategy unification was compared. RESULTS: A good correlation was observed among all assays (R>0.93). None of the samples measured by all assays showed coefficient variation (CV) <10 %, and 37 % of samples showed overall CVs >20 %. The 95 % confidence intervals (CIs) for slopes did not contain 1 for most assay pairs. Large relative biases (-85.1-104.2 %) were found, and 76 % (52-93 %) of samples had unacceptable biases. Recalibration reduced the calibration bias. Ignoring blank subtraction improved the comparability across all assays while unifying incubation did not. CONCLUSIONS: The interchangeability of PRA measurement was unsatisfying. Harmonization on calibrator and ignoring blank were recommended. Unifying incubation strategy was unnecessary.

Report from the HarmoSter study: inter-laboratory comparison of LC-MS/MS measurements of corticosterone, 11-deoxycortisol and cortisone.

OBJECTIVES: Liquid chromatography-tandem mass spectrometry (LC-MS/MS) panels that include glucocorticoid-related steroids are increasingly used to characterize and diagnose adrenal cortical diseases. Limited information is currently available about reproducibility of these measurements among laboratories. The aim of the study was to compare LC-MS/MS measurements of corticosterone, 11-deoxycortisol and cortisone at eight European centers and assess the performance after unification of calibration. METHODS: Seventy-eight patient samples and commercial calibrators were measured twice by laboratory-specific procedures. Results were obtained according to in-house and external calibration. We evaluated intra-laboratory and inter-laboratory imprecision, regression and agreement against performance specifications derived from 11-deoxycortisol biological variation. RESULTS: Intra-laboratory CVs ranged between 3.3 and 7.7%, 3.3 and 11.8% and 2.7 and 12.8% for corticosterone, 11-deoxycortisol and cortisone, with 1, 4 and 3 laboratories often exceeding the maximum allowable imprecision (MAI), respectively. Median inter-laboratory CVs were 10.0, 10.7 and 6.2%, with 38.5, 50.7 and 2.6% cases exceeding the MAI for corticosterone, 11-deoxycortisol and cortisone, respectively. Median laboratory bias vs. all laboratory-medians ranged from -5.6 to 12.3% for corticosterone, -14.6 to 12.4% for 11-deoxycortisol and -4.0 to 6.5% for cortisone, with few cases exceeding the total allowable error. Modest deviations were found in regression equations among most laboratories. External calibration did not improve 11-deoxycortisol and worsened corticosterone and cortisone inter-laboratory comparability. CONCLUSIONS: Method imprecision was variable. Inter-laboratory performance was reasonably good. However, cases with imprecision and total error above the acceptable limits were apparent for corticosterone and 11-deoxycortisol. Variability did not depend on calibration but apparently on imprecision, accuracy and specificity of individual methods. Tools for improving selectivity and accuracy are required to improve harmonization.

Comparing the results from a Swedish pregnancy cohort using data from three automated placental growth factor immunoassay platforms intended for first-trimester preeclampsia prediction.

INTRODUCTION: Risk evaluation for preeclampsia in early pregnancy allows identification of women at high risk. Prediction models for preeclampsia often include circulating concentrations of placental growth factor (PlGF); however, the models are usually limited to a specific PlGF method of analysis. The aim of this study was to compare three different PlGF methods of analysis in a Swedish cohort to assess their convergent validity and appropriateness for use in preeclampsia risk prediction models in the first trimester of pregnancy. MATERIAL AND METHODS: First-trimester blood samples were collected in gestational week 11+0 to 13+6 from 150 pregnant women at Uppsala University Hospital during November 2018 until November 2020. These samples were analyzed using the different PlGF methods from Perkin Elmer, Roche Diagnostics, and Thermo Fisher Scientific. RESULTS: There were strong correlations between the PlGF results obtained with the three methods, but the slopes of the correlations clearly differed from 1.0: PlGFPerkinElmer = 0.553 (95% confidence interval [CI] 0.518-0.588) * PlGFRoche -1.112 (95% CI -2.773 to 0.550); r = 0.966, mean difference -24.6 (95% CI -26.4 to -22.8). PlGFPerkinElmer = 0.673 (95% CI 0.618-0.729) * PlGFThermoFisher -0.199 (95% CI -2.292 to 1.894); r = 0.945, mean difference -13.8 (95% CI -15.1 to -12.6). PlGFRoche = 1.809 (95% CI 1.694-1.923) * PlGFPerkinElmer +2.010 (95% CI -0.877 to 4.897); r = 0.966, mean difference 24.6 (95% CI 22.8-26.4). PlGFRoche = 1.237 (95% CI 1.113-1.361) * PlGFThermoFisher +0.840 (95% CI -3.684 to 5.363); r = 0.937, mean difference 10.8 (95% CI 9.4-12.1). PlGFThermoFisher = 1.485 (95% CI 1.363-1.607) * PlGFPerkinElmer +0.296 (95% CI -2.784 to 3.375); r = 0.945, mean difference 13.8 (95% CI 12.6-15.1). PlGFThermoFisher = 0.808 (95% CI 0.726-0.891) * PlGFRoche -0.679 (95% CI -4.456 to 3.099); r = 0.937, mean difference -10.8 (95% CI -12.1 to -9.4). CONCLUSION: The three PlGF methods have different calibrations. This is most likely due to the lack of an internationally accepted reference material for PlGF. Despite different calibrations, the Deming regression analysis indicated good agreement between the three methods, which suggests that results from one method may be converted to the others and hence used in first-trimester prediction models for preeclampsia.

Validation of the Hem-Col capillary blood collection system for routine laboratory analyses.

At home collection of capillary blood using Hem-Col tubes (Labonovum) could offer a solution to patients with chronic conditions, who require frequent laboratory analyses. The collection tubes contain a conservation buffer to stabilize analytes for up to 5 days. In this validation study it was investigated whether analytes are measured accurately in Hem-Col tubes 5 days after collection. Forty-six healthy volunteers donated blood via venepuncture as well as capillary blood by finger prick using Hem-Col tubes. The analytes were measured within 2 h for the venepuncture and after 120 h for the Hem-Col method. The results of each analyte were analysed using Passing-Bablok regression analyses. The analytes that met the predefined acceptance criteria were total cholesterol, LDL-cholesterol, thyroid stimulating hormone (TSH) and glycated haemoglobin (HbA1c). HDL-cholesterol, C-reactive protein (CRP), ferritin, bilirubin total, creatinine, gGT and triglycerides met two out of three acceptance criteria. All other analytes did not meet the predefined criteria. The Hem-Col method is suitable for the measurement of total cholesterol, LDL-cholesterol, thyroid stimulating hormone (TSH) and glycated haemoglobin (HbA1c). However, due to this limited set of valid tests and practical limitations, routine application of this novel collection system in daily practice is limited.

Non-lethal sampling method for the analysis of white muscle fatty acid profiles in European sea bass (Dicentrarchus labrax).

This study presents a novel non-lethal sampling method for assessing fatty acid (FA) composition in juvenile European sea bass (Dicentrarchus labrax) using subcutaneous white muscle biopsies. This research aimed to evaluate the suitability of the biopsy for FA analysis using two lipid extraction protocols and comparing them to a lethal routine method. The results showed that a mass of fresh tissue as low as 1.4 mg provided good quality FA chromatograms for both reserve and membrane lipids. Although the biopsy method displayed high variability in terms of FA quantity among intra-individual replicates, it showed good FA profile repeatability in both reserve and membrane lipids. The study highlights the potential of this non-lethal approach for studying FA dynamics in fish, with its application being particularly promising for ecological and experimental studies. However, careful biopsy implementation is recommended to account for potential lipid droplet and lipid distribution variability within the tissue.

A comparative study of different methods for the determination of cadmium in various tissues of ramie (Boehmeria nivea L.).

Remediation of cadmium (Cd) pollution is one of the priorities of global environmental governance and accurate detection of Cd content is a key link in remediation of Cd pollution. This study aimed to compare three methods (inductively coupled plasma optical emission spectrometry (ICP-OES), inductively coupled plasma mass spectrometry (ICP-MS), and graphite furnace-atomic absorption spectrometry (GF-AAS)) for the determination of Cd with different tissues of various ramie varieties, and distinguish the advantage and disadvantage of each method. In total, 162 samples of ramie (Boehmeria nivea L.), which is an ideal plant for heavy metal remediation, were detected and the results showed that the three methods were all suitable for the de-termination of Cd content in ramie. ICP-OES and ICP-MS were simpler, faster, and more sensitive than GF-AAS. ICP-MS could be recommended for the determination of samples with various concentrations of Cd. ICP-OES could be used for measurement of samples with > 100 mg/kg Cd content, while GF-AAS was suitable for the detection of samples with very high (> 550 mg/kg) or very low (< 10 mg/kg) Cd content. Overall, considering the accuracy, stability, and the cost of measurement, ICP-MS was the most suitable method for determination of Cd content. This study provides significant reference information for the research in the field of Cd pollution remediation.

Analytical Variation Between Two Different TSH Reagents from the Same Manufacturer.

Thyroid stimulating hormone (TSH) immunoassays are known for giving varying results based on the platform of testing and the generation of kit used. It is generally expected that the results should not vary to affect clinical diagnosis and management. We aimed to perform method comparison study between two TSH assays by the same manufacturer Siemens Healthineers. Results show that there is a large proportional error between the assays with a bias of -3.71mIu/L indicating that TSH assay gives higher values for TSH for the same patient as measured against the TSH3-Ultra kit. This can affect interpretation of results leading to false increase in patients categorized under hypothyroidism and subclinical hypothyroidism. We strongly suggest, to prevent errors in clinical evaluation of a patient with thyroid dysfunction, validation of the performance of the assay and method comparison should be performed in-house.