BackgroundThe 2022 consensus statement of the European Atherosclerosis Society (EAS) on lipoprotein(a) (Lp(a)) recognizes the role of Lp(a) as a relevant genetically determined risk factor and... Show moreBackgroundThe 2022 consensus statement of the European Atherosclerosis Society (EAS) on lipoprotein(a) (Lp(a)) recognizes the role of Lp(a) as a relevant genetically determined risk factor and recommends its measurement at least once in an individual's lifetime. It also strongly urges that Lp(a) test results are expressed as apolipoprotein (a) (apo(a)) amount of substance in molar units and no longer in confounded Lp(a) mass units (mg/dL or mg/L). Therefore, IVD manufacturers should transition to molar units. A prerequisite for this transition is the availability of an Lp(a) Reference Measurement Procedure (RMP) that allows unequivocal molecular detection and quantification of apo(a) in Lp(a). To that end an ISO 17511:2020 compliant LC-MS based and IFCC-endorsed RMP has been established that targets proteotypic peptides of apolipoprotein(a) (apo(a)) in Lp(a). The RMP is laborious and requires highly skilled operators. To guide IVD-manufacturers of immunoassay-based Lp(a) test kits in the transition from mass to molar units, a Designated Comparison Method (DCM) has been developed and evaluated.MethodsTo assess whether the DCM provides equivalent results compared to the RMP, the procedural designs were compared and the analytical performance of DCM and RMP were first evaluated in a head-to-head comparison. Subsequently, apo(a) was quantified in 153 human clinical serum samples. Both DCM and RMP were calibrated using external native calibrators that produce results traceable to SRM2B. Measurement uncertainty (MU) was checked against predefined allowable MU.ResultsThe major difference in the design of the DCM for apo(a) is the use of only one enzymatic digestion step. The analytical performance of the DCM and RMP for apo(a) is highly similar. In a direct method comparison, equivalent results were obtained with a median regression slope 0.997 of and a median bias of - 0.2 nmol/L (- 0.2%); the intermediate imprecision of the test results was within total allowable error (TEa) (CVa of 10.2% at 90 nmol/L).ConclusionsThe semi-automated, higher throughput, LC-MS-based method for Lp(a) meets the predefined analytical performance specifications and allowable MU and is hence applicable as a higher order Designated Comparison Method, which is ideally suited to guide IVD manufacturers in the transition from Lp(a) mass to molar units. Show less
Senjor, E.; Pirro, M.; Svajger, U.; Prunk, M.; Sabotic, J.; Jewett, A.; ... ; Kos, J. 2024
Cystatin F, a cysteine peptidase inhibitor, is a potent modulator of NK cytotoxicity. By inhibiting granule-mediated cytotoxicity pathway, cystatin F induces formation of non-functional NK cell... Show moreCystatin F, a cysteine peptidase inhibitor, is a potent modulator of NK cytotoxicity. By inhibiting granule-mediated cytotoxicity pathway, cystatin F induces formation of non-functional NK cell stage, called split-anergy. We show that N-glycosylation determines the localization and cellular function of cystatin F. Cystatin F mostly exhibited high-mannose glycosylation in U-937 cells, both high-mannose and complex glycosylation in NK-92 and primary NKs, and predominantly complex glycosylation in super-charged NKs. Manipulating N-glycosylation with kifunensine increased high-mannose glycosylation of cystatin F and lysosome localisation, which decreased cathepsin C activity and reduced NK cytotoxicity. Mannose-6-phosphate could significantly reduce the internalization of extracellular cystatin F. By comparing NK cells with different cytotoxic potentials, we found that high-mannose cystatin F was strongly associated with lysosomes and cathepsin C in NK-92 cell line. In contrast, in highly cytotoxic super-charged NKs, cystatin F with complex glycosylation was associated with the secretory pathway and less prone to inhibit cathepsin C. Modulating glycosylation to alter cystatin F localisation could increase the cytotoxicity of NK cells, thereby enhancing their therapeutic potential for treating cancer patients. Show less
Background: Measures against COVID-19 in nursing homes affected not only clients but also staff. However, staff perspectives on the importance of these measures remain underexplored. Objective: To... Show moreBackground: Measures against COVID-19 in nursing homes affected not only clients but also staff. However, staff perspectives on the importance of these measures remain underexplored. Objective: To investigate measures related to staff during the COVID-19 pandemic, staff perspectives of important measures and the involvement of staff in deciding on these measures. Design: A qualitative study. Setting(s): We analysed minutes of nursing home outbreak teams in the Netherlands and conducted group meetings with Dutch nursing home staff in different positions, prioritizing measures and discussing staff' involvement in deciding on the measures. Participants were recruited purposefully. Participants: The minutes of 41 nursing home organizations were collected during March-November, 2020. Four group meetings were organized in the same period, each with 5 to 7 participants, resulting in 23 participants. Methods: The meeting minutes were analysed using qualitative content analysis, whereas reflexive thematic analysis was used for the group meeting data. The group meetings were conducted online and structured by the Nominal Group Technique to discuss the importance of measures for staff. Results: Measures implemented for staff focused on prevention of COVID-19 transmission, (suspension of) educational activities, testing, additional tasks and staffing capacity, promoting wellbeing, and other means of support. The implemented measures overlapped with the measures considered important by staff. In addition, staff considered measures on decision-making support and communication to be important. Staff prioritized the measures in the group meetings because they affected their well-being, workforce scheduling, decision-making, or infection prevention. Furthermore, the group meetings revealed that decision-making shifted from mainly implementing national measures to more context-adjusted decision-making in the staff's or clients' situations. Conclusions: We showed that although nursing home staff were not always involved in decisionmaking during the first COVID-19 wave, there was overlap between the measures implemented by the organizations and measures considered important by staff. We suggest that organizations Show less
Rede uitgesproken door Prof. dr. Anton Jan van Zonneveld ter gelegenheid van zijn afscheid als hoogleraarNierziekten, in het bijzonder de experimentele vasculaire geneeskunde aan de Universiteit... Show moreRede uitgesproken door Prof. dr. Anton Jan van Zonneveld ter gelegenheid van zijn afscheid als hoogleraarNierziekten, in het bijzonder de experimentele vasculaire geneeskunde aan de Universiteit Leiden op vrijdag 31 mei 2024 Show less
Background: The risk of urinary tract infections (UTIs) is increased by unnecessary placement and prolonged use of urinary catheters. Aim: To assess whether inappropriate use of catheters and... Show moreBackground: The risk of urinary tract infections (UTIs) is increased by unnecessary placement and prolonged use of urinary catheters. Aim: To assess whether inappropriate use of catheters and catheter-associated UTI were reduced through patient participation. Methods: In this multicentre, interrupted time-series and before-and-after study, we implemented a patient-centred app which provides catheter advice for patients, together with clinical lessons, feedback via e-mails and support rounds for staff members. Data on catheter use and infections were collected during a six-month baseline and a six-month intervention period on 13 wards in four hospitals in the Netherlands. Dutch Trial Register: NL7178. Findings: Between June 25th, 2018 and August 1st, 2019, 6556 patients were included in 24 point-prevalence surveys, 3285 (50%) at baseline and 3271 (50%) during the intervention. During the intervention 249 app users and a median of seven new app users per week were registered (interquartile range: 5.5e13.0). At baseline, inappropriate catheter use was registered for 175 (21.9%) out of 798 catheters, compared to 55 (7.0%) out of 786 during the intervention. Time-series analysis showed a non-significant decrease of inappropriate use of 5.8% (95% confidence interval: e3.76 to 15.45; P ¼ 0.219), with an odds ratio of 0.27 (0.19e0.37; P < 0.001). Catheter-associated UTI decreased by 3.0% (1.3e4.6; P ¼ 0.001), with odds ratio 0.541 (0.408e0.716; P < 0.001). Show less
BackgroundWhen research evidence is limited, inconsistent, or absent, healthcare decisions and policies need to be based on consensus among interested stakeholders. In these processes, the... Show moreBackgroundWhen research evidence is limited, inconsistent, or absent, healthcare decisions and policies need to be based on consensus among interested stakeholders. In these processes, the knowledge, experience, and expertise of health professionals, researchers, policymakers, and the public are systematically collected and synthesised to reach agreed clinical recommendations and/or priorities. However, despite the influence of consensus exercises, the methods used to achieve agreement are often poorly reported. The ACCORD (ACcurate COnsensus Reporting Document) guideline was developed to help report any consensus methods used in biomedical research, regardless of the health field, techniques used, or application. This explanatory document facilitates the use of the ACCORD checklist.Methods and findingsThis paper was built collaboratively based on classic and contemporary literature on consensus methods and publications reporting their use. For each ACCORD checklist item, this explanation and elaboration document unpacks the pieces of information that should be reported and provides a rationale on why it is essential to describe them in detail. Furthermore, this document offers a glossary of terms used in consensus exercises to clarify the meaning of common terms used across consensus methods, to promote uniformity, and to support understanding for consumers who read consensus statements, position statements, or clinical practice guidelines (CPGs). The items are followed by examples of reporting items from the ACCORD guideline, in text, tables, and figures.ConclusionsThe ACCORD materials—including the reporting guideline and this explanation and elaboration document—can be used by anyone reporting a consensus exercise used in the context of health research. As a reporting guideline, ACCORD helps researchers to be transparent about the materials, resources (both human and financial), and procedures used in their investigations so readers can judge the trustworthiness and applicability of their results/recommendations. Show less
The global trade of plastic waste has raised environmental concerns, especially regarding pollution in waste-importing countries. However, the overall environmental contribution remains unclear due... Show moreThe global trade of plastic waste has raised environmental concerns, especially regarding pollution in waste-importing countries. However, the overall environmental contribution remains unclear due to uncertain treatment shares between handling plastic waste abroad and domestically. Here, we conduct a life cycle assessment of global plastic waste trade in 2022 across 18 countries and six plastic waste types, alongside three “nontrade” counterfactual scenarios. By considering the required cycling rate, which balances importers’ costs and recycling revenues, we find that the trade resulted in lower environmental impacts than treating domestically with the average treatment mix. The trade scenario alone reduced climate change impact by 2.85 million tonnes of CO2 equivalent and mitigated damages to ecosystem quality, human health, and resource availability by 12 species-years, 6200 disability-adjusted life years (DALYs), and 1.4 billion United States dollars (USD in 2013), respectively. These results underscore the significance of recognizing plastic waste trade as a pivotal factor in regulating global secondary plastic production when formulating a global plastics treaty. Show less
A group of bacterial proteases, the Pro-Pro endopeptidases (PPEPs), pos-sess the unique ability to hydrolyze proline-proline bonds in proteins. Sincea protease’s function is largely determined by... Show moreA group of bacterial proteases, the Pro-Pro endopeptidases (PPEPs), pos-sess the unique ability to hydrolyze proline-proline bonds in proteins. Sincea protease’s function is largely determined by its substrate specificity,methods that can extensively characterize substrate specificity are valuabletools for protease research. Previously, we achieved an in-depth characteri-zation of PPEP prime-side specificity. However, PPEP specificity is alsodetermined by the non-prime-side residues in the substrate. To gain a morecomplete insight into the determinants of PPEP specificity, we character-ized the non-prime- and prime-side specificity of various PPEPs using acombination of synthetic combinatorial peptide libraries and mass spec-trometry. With this approach, we deepened our understanding of the P3-P30 specificities of PPEP-1 and PPEP-2, while identifying the endogenoussubstrate of PPEP-2 as the most optimal substrate in our library data. Fur-thermore, by employing the library approach, we investigated the alteredspecificity of mutants of PPEP-1 and PPEP-2. Additionally, we character-ized a novel PPEP from Anoxybacillus tepidamans, which we termed PPEP-4. Based on structural comparisons, we hypothesized that PPEP-4 displaysa PPEP-1-like prime-side specificity, which was substantiated by the experi-mental data. Intriguingly, another putative PPEP from Clostridioides diffi-cile, CD1597, did not display Pro-Pro endoproteolytic activity.Collectively, we characterized PPEP specificity in detail using our robustpeptide library method and, together with additional structural informa-tion, provide more insight into the intricate mechanisms that govern prote-ase specificity. Show less
Honings, R.A.M.; Bosnak, J.E.; Veer, C.B. van 't 2024
High-grade osteosarcoma, a primary malignant bone tumour, is experiencing a global increase in reported incidence with varied prevalence. Despite advances in management, which include surgery and... Show moreHigh-grade osteosarcoma, a primary malignant bone tumour, is experiencing a global increase in reported incidence with varied prevalence. Despite advances in management, which include surgery and neoadjuvant chemotherapy often an unsatisfactory outcome is found due to poor or heterogeneous response to chemotherapy. Our study delved into chemotherapy responses in osteosarcoma patients and associated molecular expressions, focusing on CD95 receptor (CD95R), interferon (IFN)-γ, catalase, heat-shock protein (Hsp)70, and vascular endothelial growth factor (VEGF). Employing immunohistochemistry and Huvos grading of post-chemo specimens, we analysed formalin-fxed parafn-embedded (FFPE) osteosarcoma tissue of resected post-chemotherapy specimens from Dr. Soetomo General Academic Hospital in Surabaya, Indonesia (DSGAH), spanning from 2016 to 2020. Results revealed varied responses (poor 40.38%, moderate 48.08%, good 11.54%) and distinct patterns in CD95R, IFN-γ, catalase, Hsp70, and VEGF expression. Signifcant diferences among response groups were observed in CD95R and IFN-γ expression in tumour-infltrating lymphocytes. The trend of diminishing CD95R expression from poor to good responses, accompanied by an increase in IFN-γ, implied a reduction in the count of viable osteosarcoma cells with the progression of Huvos grading. Catalase expression in osteosarcoma cells was consistently elevated in the poor response group, while Hsp70 expression was highest. VEGF expression in macrophages was signifcantly higher in the good response group. In conclusion, this study enhances our understanding of immune-chemotherapy interactions in osteosarcoma and identifes potential biomarkers for targeted interventions. Show less
AimsCustom triflange acetabular components (CTACs) play an important role in reconstructive orthopaedic surgery, particularly in revision total hip arthroplasty (rTHA) and pelvic tumour resection... Show moreAimsCustom triflange acetabular components (CTACs) play an important role in reconstructive orthopaedic surgery, particularly in revision total hip arthroplasty (rTHA) and pelvic tumour resection procedures. Accurate CTAC positioning is essential to successful surgical outcomes. While prior studies have explored CTAC positioning in rTHA, research focusing on tumour cases and implant flange positioning precision remains limited. Additionally, the impact of intraoperative navigation on positioning accuracy warrants further investigation. This study assesses CTAC positioning accuracy in tumour resection and rTHA cases, focusing on the differences between preoperative planning and postoperative implant positions.MethodsA multicentre observational cohort study in Australia between February 2017 and March 2021 included consecutive patients undergoing acetabular reconstruction with CTACs in rTHA (Paprosky 3A/3B defects) or tumour resection (including Enneking P2 peri-acetabular area). Of 103 eligible patients (104 hips), 34 patients (35 hips) were analyzed.ResultsCTAC positioning was generally accurate, with minor deviations in cup inclination (mean 2.7°; SD 2.84°), anteversion (mean 3.6°; SD 5.04°), and rotation (mean 2.1°; SD 2.47°). Deviation of the hip centre of rotation (COR) showed a mean vector length of 5.9 mm (SD 7.24). Flange positions showed small deviations, with the ischial flange exhibiting the largest deviation (mean vector length of 7.0 mm; SD 8.65). Overall, 83% of the implants were accurately positioned, with 17% exceeding malpositioning thresholds. CTACs used in tumour resections exhibited higher positioning accuracy than rTHA cases, with significant differences in inclination (1.5° for tumour vs 3.4° for rTHA) and rotation (1.3° for tumour vs 2.4° for rTHA). The use of intraoperative navigation appeared to enhance positioning accuracy, but this did not reach statistical significance.ConclusionThis study demonstrates favourable CTAC positioning accuracy, with potential for improved accuracy through intraoperative navigation. Further research is needed to understand the implications of positioning accuracy on implant performance and long-term survival. Show less
Objectives To compare the effectiveness of longstanding (>52 weeks), supervised exercise therapy with usual care in adults with rheumatoid arthritis (RA) and severe functional limitations.Methods P... Show moreObjectives To compare the effectiveness of longstanding (>52 weeks), supervised exercise therapy with usual care in adults with rheumatoid arthritis (RA) and severe functional limitations.Methods Participants were randomised 1:1 to the intervention (individualised goal-setting, active exercises, education and self-management regarding physical activity) or usual care. Primary endpoint was the change in the Patient-Specific Complaints activity ranked 1 (PSC1, 0–10) at 52 weeks. Secondary endpoints included the PSC activities ranked 2 and 3 (PSC2, PSC3), Health Assessment Questionnaire-Disability Index (HAQ-DI), Rheumatoid Arthritis Quality of Life Questionnaire (RAQoL), 6-minute walk test (6MWT), Patient Reported Outcome Measurement Information System Physical Function-10 (PROMIS PF-10) and the Short Form-36 Physical and Mental Component Summary Scales (SF-36 PCS and MCS). (Serious) Adverse events (AEs) were recorded. Measurements were done by blinded assessors. Analyses at 52 weeks were based on the intention-to-treat principle.Results In total, 217 people (90% female, age 58.8 (SD 12.9) years) were randomised (n=104 intervention, n=98 usual care available for analyses). At 52 weeks, the improvement of the PSC1 was significantly larger in the intervention group (mean difference (95% CI) −1.7 (−2.4, –1.0)). Except for the SF-36 MCS, all secondary outcomes showed significantly greater improvements favouring the intervention (PSC2 −1.8 (−2.4, –1.1), PSC3 −1.7 (−2.4, −1.0), PROMIS PF-10 +3.09 (1.80, 4.38), HAQ-DI −0.17 (−0.29, –0.06), RAQoL −2.03 (−3.39, –0.69), SF-36 PCS +3.83 (1.49, 6.17) and 6MWT +56 (38, 75) m). One mild, transient AE occurred in the intervention group.Conclusion Longstanding, supervised exercise therapy was more effective than usual care in people with RA and severe functional limitations. Show less
Dijk, B.T. van; Boeren, A.M.P.; Khidir, S.J.H.; Hollander, N.K. den; Helm-van Mil, A.H.M. van der 2024
Objectives Rheumatoid arthritis (RA) mainly affects small joints. Despite the mechanical function of joints, the role of mechanical stress in the development of arthritis is insufficiently... Show moreObjectives Rheumatoid arthritis (RA) mainly affects small joints. Despite the mechanical function of joints, the role of mechanical stress in the development of arthritis is insufficiently understood. We hypothesised that mechanical stress/physical strain is a risk factor for joint inflammation in RA. Therefore, we studied work-related physical strain in subjects with clinically suspected arthralgia (CSA) as a risk factor for the presence of imaging-detected subclinical joint inflammation and the development of clinical arthritis/RA. Methods In 501 CSA patients and 155 symptom-free persons’ occupation-related physical strain was quantified using the International Standard Classification of Occupations. Contrastenhanced hand-MRIs were made and evaluated for joint inflammation (sum of synovitis/tenosynovitis/osteitis). CSA patients were followed on RA development. Age relationship was studied using an interaction term of physical strain with age. Results The degree of physical strain in CSA is associated with the severity of joint inflammation, independent of educational-level/BMI/smoking (interaction physical strain-age p=0.007; indicating a stronger association with increasing age). Physical strain is associated with higher tenosynovitis scores, in particular. In symptom-free persons, physical strain was not associated with imaging-detected joint inflammation. Higher degrees of physical strain also associated with higher risks for RA development in an age-dependent manner (HR=1.20 (1.06–1.37)/10-year increase in age), independent of educational-level/BMI/smoking. This association was partly mediated by an effect via subclinical joint inflammation. Conclusions Work-related physical strain increases the risk of subclinical joint inflammation and of developing RA. The age relationship suggests an effect of long-term stress or that tenosynovium is more sensitive to stress at older age. Together, the data indicate that mechanical stress contributes to the development of arthritis in RA. Show less
BackgroundThis was a cross-sectional study on the correlation between abdominal aortic calcification (AAC) and Modic changes (MC). Little is known regarding the etiology of MC in the lumbar spine.... Show moreBackgroundThis was a cross-sectional study on the correlation between abdominal aortic calcification (AAC) and Modic changes (MC). Little is known regarding the etiology of MC in the lumbar spine. Currently, insufficient vascularization of the endplate has been proposed to contribute to the appearance of MC. Our objective was to investigate whether AAC, a marker for a poor vascular status, is associated with MC in patients suffering from degenerative disc disease.MethodsRadiologic images of patients (n = 130) suffering from degenerative lumbar disc disease were reviewed. Type and severity of MC were assessed using magnetic resonance images, and severity of AAC was evaluated using computed tomography images or fluoroscopy. Both items were dichotomized into minimal and relevant grades. The correlation between them was studied using Spearman's correlation test, with age as a covariate.ResultsOf the patients, 113 (87%) demonstrated MC (31% type I, 63% type II, and 6% type III) (55% relevant grade), and 68% had AAC (44% relevant grade). Spearman statistical analysis revealed that AAC was correlated with age (P < 0.001), whereas MC were not (P = 0.142). AAC severity was significantly correlated with MC, remaining so after age adjustment (P < 0.05). While MC type I lacked correlation with AAC, MC type II were significantly correlated with AAC (0.288, P = 0.015); however, this association lost significance after adjusting for age (P = 0.057).ConclusionsAAC and MC (mainly MC type II) are associated, indicating that reduced blood supply or even a poor systemic vascularization status due to atherosclerotic disease may play a role in the formation of MC. Future studies focusing on the etiology of MC should pay more attention to patients' vascular status and determinants of abdominal aorta calcification. Show less
Introduction Diabetic foot ulcers are feared complications of diabetes mellitus (DM), requiring extensive treatment and hospital admissions, ultimately leading to amputation and increased mortality... Show moreIntroduction Diabetic foot ulcers are feared complications of diabetes mellitus (DM), requiring extensive treatment and hospital admissions, ultimately leading to amputation and increased mortality. Different factors contribute to the development of foot ulcers and related complications. Onychomycosis, being more prevalent in patients with diabetes, could be an important risk factor for developing ulcers and related infections. However, the association between onychomycosis and diabetic complications has not been well studied in primary care.Research design and methods To determine the impact of onychomycosis on ulcer development and related complications in patients with diabetes in primary care, a longitudinal cohort study was carried out using routine care data from the Extramural Leiden University Medical Center Academic Network. Survival analyses were performed through Cox proportional hazards models with time-dependent covariates.Results Data from 48 212 patients with a mean age of 58 at diagnosis of DM, predominantly type 2 (87.8%), were analysed over a median follow-up of 10.3 years. 5.7% of patients developed an ulcer. Onychomycosis significantly increased the risk of ulcer development (HR 1.37, 95% CI 1.13 to 1.66), not affected by antimycotic treatment, nor after adjusting for confounders (HR 1.23, 95% CI 1.01 to 1.49). The same was found for surgical interventions (HR 1.54, 95% CI 1.35 to 1.75) and skin infections (HR 1.48, CI 95% 1.28 to 1.72), again not affected by treatment and significant after adjusting for confounders (HR 1.32, 95% CI 1.16 to 1.51 and HR 1.27, 95% CI 1.10 to 1.48, respectively).Conclusions Onychomycosis significantly increased the risk of ulcer development in patients with DM in primary care, independently of other risk factors. In addition, onychomycosis increased the risk of surgeries and infectious complications. These results underscore the importance of giving sufficient attention to onychomycosis in primary care and corresponding guidelines. Early identification of onychomycosis during screening and routine care provides a good opportunity for timely recognition of increased ulcer risk. Show less
Calibration of prothrombin time (PT) in terms of international normalized ratio (INR) has been outlined in “Guidelines for thromboplastins and plasmas used to control oral anticoagulant therapy” ... Show moreCalibration of prothrombin time (PT) in terms of international normalized ratio (INR) has been outlined in “Guidelines for thromboplastins and plasmas used to control oral anticoagulant therapy” (World Health Organization, 2013). The international standard ISO 17511:2020 presents requirements for manufacturers of in vitro diagnostic (IVD) medical devices (MDs) for documenting the calibration hierarchy for a measured quantity in human samples using a specified IVD MD. The objective of this article is to define an unequivocal, metrologically traceable calibration hierarchy for the INR measured in plasma as well as in whole blood samples. Calibration of PT and INR for IVD MDs according to World Health Organization guidelines is similar to that in cases where there is a reference measurement procedure that defines the measurand for value assignment as described in ISO 17511:2020. We conclude that, for PT/INR standardization, the optimal calibration hierarchy includes a primary process to prepare an international reference reagent and measurement procedure that defines the measurand by a value assignment protocol conforming to clause 5.3 of ISO 17511:2020. A panel of freshly prepared human plasma samples from healthy adult individuals and patients on vitamin K antagonists is used as a commutable secondary calibrator as described in ISO 17511:2020. A sustainable metrologically traceable calibration hierarchy for INR should be based on an international protocol for value assignment with a single primary reference thromboplastin and the harmonized manual tilt tube technique for clotting time determination. The primary international reference thromboplastin reagent should be used only for calibration of successive batches of the secondary reference thromboplastin reagent Show less
