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Publications (345)
The main stakeholders in external quality assessment (EQA) programs are the participants, in whose interests these challenges are ultimately organised. EQA schemes in the medical field contribute to improving the quality of patient care by evaluating the analytical and diagnostic quality of laboratory and point-of-care tests (POCT) by independent t...
External quality assessment (EQA) cycles are the smallest complete units within EQA programs that laboratories can use to obtain external assessments of their performance. In each cycle, several samples are distributed to the laboratories registered for participation, and ideally, EQA programs not only cover the examination procedures but also the...
Providers of external quality assessment (EQA) programs evaluate data or information obtained and reported by participant laboratories using their routine procedures to examine properties or measurands in samples provided for this purpose. EQA samples must offer participants an equal chance to obtain accurate results, while being designed to provid...
Zusammenfassung
Hintergrund und Ziele
Die zeitgerechte Bestimmung und Bewertung von Laborparametern bei Patienten mit akuten lebens- oder organbedrohlichen Erkrankungen und Erkrankungszuständen in der Notaufnahme oder auf Intensivstationen kann für die Diagnosestellung, den Therapiebeginn und das Ergebnis essenziell sein. Ziel des Positionspapiers...
Purpose
A host-protein signature score, consisting of serum-concentrations of C-reactive protein, tumour necrosis factor-related apoptosis-inducing ligand, and interferon gamma-induced protein 10, was validated for distinguishing between bacterial and viral infections as an antimicrobial stewardship measure for routine clinical practice among adult...
Point-of-care testing (POCT) is becoming an increasingly popular way to perform laboratory tests closer to the patient. This option has several recognized advantages, such as accessibility, portability, speed, convenience, ease of use, ever-growing test panels, lower cumulative healthcare costs when used within appropriate clinical pathways, better...
Background: Epstein-Barr virus-associated Infectious Mononucleosis (EBV-IM) is a common disease following primary EBV infection in children and adolescents. While EBV-IM is mostly self-limiting, symptoms like fatigue may persist over several months or even result in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). This large clinical ob...
Objectives
This study aimed to evaluate discrepancies in potassium measurements between point-of-care testing (POCT) and central laboratory (CL) methods, focusing on the impact of hemolysis on these measurements and its impact in the clinical practice in the emergency department (ED).
Methods
A retrospective analysis was conducted using data from...
Background
During the last decade, Germany has seen an increased prevalence and a redistribution from undetected to diagnosed diabetes mellitus. Due to this substantial epidemiological development, the number of people with documented type 2 diabetes was 8.7 million in 2022. An estimated two million undiagnosed subjects are to be added. Beyond that...
The programme of the German Congress for Laboratory Medicine 2022 was essentially designed by the divisions of the German Society for Clinical Chemistry and Laboratory Medicine (DGKL). Almost all chairpersons of the divisions organised a 90-min symposium on current topics, i.e. conceptualised the symposia and invited speakers. For this article all...
As hormonal disorders are linked to several diseases, the accurate quantitation of steroid hormone levels in serum is crucial in order to provide patients with a reliable diagnosis. Mass spectrometry-based methods are regarded as having the highest level of specificity and sensitivity. However, immunoassays are more commonly used in routine diagnos...
Objective:
To investigate whether goal-directed albumin substitution during surgery and postanesthesia care to maintain a serum albumin concentration >30 g/L can reduce postoperative complications.
Summary background data:
Hypoalbuminemia is associated with numerous postoperative complications. Since albumin has important physiological functions...
Personalized assessment of vitamin levels in point-of-care (POC) devices is urgently needed to advance the recognition of diseases associated with malnutrition and unbalanced diets. We here introduce a diagnostic platform, which showcases an easy and rapid readout of vitamin B6 (pyridoxal phosphate, PLP) levels in erythrocytes as a first step towar...
Background:
European legislation defines as "near-patient testing" (NPT) what is popularly and in other legislations specified as "point-of-care testing" (POCT). Systems intended for NPT/POCT use must be characterized by independence from operator activities during the analytic procedure. However, tools for evaluating this are lacking. We hypothes...
Objectives
The therapeutic antibody infliximab (IFX) has improved the life quality of numerous autoinflammatory disease patients. However, IFX can trigger the generation of anti-drug antibodies (ADA), whose optimal evaluation and management are currently subject of controversial discussions. We present two novel surface plasmon resonance (SPR) bios...
The interaction between programmed death-1 receptor PD-1 and its ligands PD-L1 and PD-L2 is involved in self-tolerance, immune escape of cancer, cardiovascular diseases, and COVID-19. As blood-based protein markers they bear great potential to improve oncoimmunology research and monitoring of anti-cancer immunotherapy. A variety of preanalytical co...
Extended cut-off filtration by medium cut-off membranes (MCO) has been shown to be safe in maintenance hemodialysis (HD). The notion of using them for the control of chronic low-grade inflammation and positively influencing cellular immune aberrations seems tempting. We conducted an open label, multicenter, randomized, 90 day 2-phase cross over cli...
Programmed death-1 receptor PD-1(CD279) and its corresponding ligands PD-L1(CD274, B7-H1) and PD-L2(CD273, B7-DC) play important roles in physiological immune tolerance and for immune escape in cancer disease. Hence, the establishment and analytical validation of a novel enzyme-linked immunosorbent assay (ELISA) to measure soluble PD-1, PD-L1 and P...
Objectives
Proposal of a risk analysis model to diminish negative impact on patient care by preanalytical errors in blood gas analysis (BGA).
Methods
Here we designed a Failure Mode and Effects Analysis (FMEA) risk assessment template for BGA, based on literature references and expertise of an international team of laboratory and clinical health c...
The relationship between SARS-CoV-2 quantitative viral load and risk of disease progression, morbidity such as long-COVID or mortality in immunosuppressed, remains largely undefined in COVID-19 patients. Critically ill immunosuppressed patients potentially benefit from remdesivir treatment because of the prolonged course of their infection. Four cr...
Zusammenfassung
Die Messung von spezifischen Autoantikörpern gegen beta-Zellproteine (beta-AAK) hat in den letzten Jahren das diagnostische Repertoire in der Diabetologie erweitert. Das Vorliegen von beta-AAK kann als erstes Stadium in der Entwicklung eines Typ-1-Diabetes mellitus (DM) gewertet werden, ohne dass Symptome bzw. metabolische Veränderu...
The present paper describes a compact point of care (POC) optical device for therapeutic drug monitoring (TDM). The core of the device is a disposable plastic chip where an immunoassay for the determination of immunosuppressants takes place. The chip is designed in order to have ten parallel microchannels allowing the simultaneous detection of more...
Ein patientennaher molekularer Nachweis von akuten viralen Atemwegsin- fektionen ermöglicht eine Identifizierung von Betroffenen im Frühstadium der Infektion durch den direkten Nachweis der Viruslast ohne zeitaufwen- dige Viruskultur. Die SARS-CoV-2-Pandemie hat die Geräteentwicklung in diesem Bereich revolutioniert.
Background: The inflammation modulator infliximab (IFX), a therapeutic antibody for therapy of inflammatory bowel disease (IBD) and rheumatic disorders, has proven to be a powerful tool to achieve remission and improve life quality. However, about a third of IFX-treated IBD patients develop anti-drug antibodies (ADA) that are associated with second...
Blood gas analysis at or near the patient’s bedside is a common practice in acute medicine and plays a crucial role in the diagnosis and management of patient’s respiratory status, metabolites, electrolytes, co-oximetry and acid–base balance. Pre-analytical quality aspects of the specimens are getting more and more attention, including the presence...
Objective:
To investigate the effect of convalescent plasma therapy (CPT) on clinical courses of B-cell-sufficient and B-cell-depleted patients with life-threatening COVID-19.
Patients and methods:
In this case series, we retrospectively analysed clinical, laboratory and cardiopulmonary parameters of six patients with life-threatening COVID-19 r...
Aim: This 12-month study was conducted to evaluate the skeletal effects of two monophasic oral contraceptives containing 20 Ag of ethinylestradiol and 100 Ag of levonorgestrel (LEVO) or 150 Ag of desogestrel (DESO).
Methods: Fifty-two women (18–24 years) were randomized into the DESO group or the LEVO group; 36 women served as controls. The areal b...
Background
Antibodies to infliximab (ATI) in serum are associated with secondary loss of response (LOR) to infliximab (IFX) therapy in patients with inflammatory bowel disease (IBD). However, feasible ATI-related predictors of therapy success are lacking and knowledge about individual ATI dynamics is limited. Therefore, this study analyzed whether...
Background
Tests for diagnosing infectious diseases (ID-POCT) play a special role among the available point-of-care testing (POCT) methods.
Methods
A systematic literature search was performed in PubMed. Based on this literature review and our own experience, aspects associated with using molecular biological methods in the diagnostic amplificatio...
Objectives
Therapeutic drug monitoring (TDM) plays a crucial role in personalized medicine. It helps clinicians to tailor drug dosage for optimized therapy through understanding the underlying complex pharmacokinetics and pharmacodynamics. Conventional, non-continuous TDM fails to provide real-time information, which is particularly important for t...
Background
Hypalbuminemia is associated with numerous postoperative complications, so a perioperative albumin substitution is often considered. The objective of SuperAdd is to investigate whether substitution of human albumin, aiming to maintain a serum concentration > 30 g/l, can reduce postoperative complications in normovolemic surgical patients...
The extent of the involvement of platelets in venous thromboembolisms (VTE) is still not fully understood. Immature platelets are large, RNA-rich, prothrombotic platelets. They are involved in arterial thromboembolisms and are associated with adverse cardiovascular events. Their role in VTE has not been investigated before. The aim of this study wa...
Background
Quality assurance (QA) in point-of-care testing (POCT) is an important issue for organizing POCT structures within the healthcare sector. In Germany, only one device needs to participate in an external QA program, if the responsible core laboratory is supervising internal quality controls of all other identical POCT devices. This flexibl...
Background:
Point-of-care tests (POCT) measure analytes close to the patients and are a complementary supplement to the test menu of medical laboratories. However, the involvement of many different stakeholders makes it challenging to ensure reliable results.
Methods:
In a survey, we asked experienced POCT users how they control their total POCT...
Tumor necrosis factor (TNF) acts as a proinflammatory messenger in autoimmune diseases and hence serves as drug target for symptomatic disease management. Even though widely prescribed, treatment of patients with biologic TNF antagonists, e.g. infliximab (IFX), results in broadly diverging outcomes. Emergence of anti-drug antibodies (ADAs) is a maj...
Background
Persistent antiphospholipid antibodies (aPL) constitute the serological hallmark of the antiphospholipid syndrome (APS). Recently, various new assay technologies for the detection of aPL better suited to multiplex reaction environments than ELISAs emerged. We evaluated the diagnostic performance of such a novel line immunoassay (LIA) for...
Immunodiagnostic tests performed at the point of care (POC) today usually employ antibodies for biorecognition and are read out either visually or with specialized equipment. Availability of alternative biorecognition elements with promising features as well as smartphone-based approaches for signal readout, however, challenge the described establi...
Immunological methods are widely applied in medical diagnostics for the detection and quantification of a plethora of analytes. Associated analytical challenges usually require these assays to be performed in a central laboratory. During the last several years, however, the clinical demand for rapid immunodiagnostics to be performed in the immediat...
Background:
Dilated cardiomyopathy (DCM) is a common cause of heart failure with high morbidity and mortality rates. The association of anti-β1 adrenergic receptor (β1AR) autoantibodies with disease progression was shown by various studies and in vivo animal experiments. The prevalence of these disease-driving autoantibodies was estimated as 25% t...
Die Labormedizin hat die Aufgabe, durch Messung physikalischer, hämatologischer, molekularbiologischer und (bio)chemischer Eigenschaften von menschlichem Untersuchungsmaterial gezielt gestellte ärztliche Fragen im Hinblick auf Diagnostik, Therapieverlauf, Prävention und Prognose von Krankheiten zu beantworten. Relevante Kenngrößen werden in dem Kap...
In diesem Kapitel werden die Referenzwerte der wichtigsten Laborparameter – in Serum und Urin – sowie die Umrechenfaktoren von konventionellen zu SI-Einheiten tabellarisch aufgeführt.
Point-of-care tests (POCT) measure analytes close to the patients and complementary supplement the test menu of medical laboratories. However, the involvement of many different stakeholders makes it challenging to ensure reliable results. In a survey, we asked experienced POCT users how they control their total POCT process and what factors they co...
The underlying technology and the range of test parameters available are evolving rapidly. The primary advantage of POCT is the convenience of performing the test close to the patient and the speed at which test results can be obtained, compared to sending a sample to a laboratory and waiting for results to be returned. Thus, a series of clinical a...
The exceptional toxicity of botulinum neurotoxins (BoNTs) is mediated by high avidity binding to complex polysialogangliosides and intraluminal segments of synaptic vesicle proteins embedded in the presynaptic membrane. One peculiarity is an exposed hydrophobic loop in the toxin’s cell binding domain HC, which is located between the ganglioside- an...
Representative SDS-PAGE of GST pull down of wild-type and ΔHC loop-mutants of HCB, HCDC, and HCG by GST-synaptotagmin-II with or without gangliosides in Triton X-100 micelles.
Binding of 100 pmol of the wild-type or ΔHC loop HC fragments to 150 pmol GST, GST-rSyt-II 1–61, GST-rSyt-II 1–90 in 20 mM Tris pH 8, 80 mM NaCl, 0.5% Triton X-100 in the pre...
Correlation between binding affinity determined by the indicated receptor molecules incorporated in Triton X-100 micelles by pull-down assay (given as Mol% binding) and incorporated in nanodiscs by SPR (given as Affinity in M).
Highly significant (p < 0.0001) and close (Spearman r = -0.91) correlation between binding affinities determined by SPR an...
Additional purification of GST-rSyt-II containing nanodiscs via GST-pull down.
Batch purification via the GST-tag using glutathione-agarose was used to separate receptor-bearing nanodiscs from empty nanodiscs. A. Colloidal Coomassie-stained gels for pooled nanodiscs containing fractions after SEC (input), supernatant (SN) of GST-pull-down material,...
Binding kinetics and affinity data used to deduct thermodynamic binding parameters.
Different values for same conditions indicate repeated measurements.
(DOCX)
A Alignment of BoNT/B subtypes 1–8, BoNT/DC, and BoNT/G amino acid sequences covering the region of the hydrophobic HC loop (marked by boxes based on superimposition of crystal structures). Multiple sequence alignments were performed using Geneious 10.0.5 (global alignment with free end gaps employing the Blosum62 cost matrix) and the NCBI-Protein...
Van’t Hoff plots for deduction of thermodynamic binding parameters.
The natural logarithm (ln) of the binding affinities KD was plotted over 1 divided by the measurement temperature for binding of HCB to isolated Syt-II (A), Syt-II incorporated into nanodiscs (B), and HCB ΔG1247-F1250 and HCB binding to dual-receptor nanodisc (C and D, respectively...
Binding specificity of the antibodies used in this study.
Either 5 μL of rat brain extract or 562.5 ng of the indicated proteins were loaded on 12% PAA gels which were subsequently stained by colloidal Coomassie (A) or transferred to PVDF-membranes and probed with a mouse anti-His (1:10,000; B) or a rabbit anti-synaptotagmin 2 (1:5,000; C) antibody...
Background
Determination of blood glucose concentration is one of the most important measurements in clinical chemistry worldwide. Analyzers in central laboratories (CL) and point-of-care tests (POCT) are both frequently used. In Germany, regular participation in external quality assessment (EQA) schemes is mandatory for laboratories performing glu...
Therapeutic drug monitoring (TDM) of the immunosuppressive drug tacrolimus is essential to avoid side effects and rejection of the allograft after transplantation. In the blood circulation, tacrolimus is largely located inside erythrocytes or bound to plasma proteins and less than 0.1% is protein-unbound (free). One basic principle of clinical phar...
Background:
Amino acid co-infusion for renal protection in endoradiotherapy (ERT) applied as prostate-specific membrane antigen (PSMA)-targeted radioligand therapy (RLT) or peptide receptor radionuclide therapy (PRRT) has been shown to cause severe hyperkalemia. The pathophysiology behind the rapid development of hyperkalemia is not well understoo...
This chapter shows how important comprehensive electronic networks linking POCT devices in hospitals are to coordinate POCT activities centrally. It also details the fundamentals of data processing and data management for decentralized POCT measurements from the networking perspective.
The market for POCT devices can be called labyrinthine – its intricate spectrum of methods spanning from simple test strips to complex immunochemical assays. It therefore makes sense to align a categorization of this technology along the following system characteristics: Sensor characteristics, system complexity, measurement principles, sample matr...
Near-patient laboratory diagnostics has a long history and is now an indispensable part of clinical medicine. On the one hand, devices incorporating POCT fulfill the medical rationale of shortening the time from blood draw to treatment decision. On the other, POCT analyzers can also be provided for organizational reasons, rendering feasible options...
The cardiac specific troponins (cTn) are the preferred biomarkers for the diagnosis of myocardial infarction. They are measured quantitatively in the serum. The use of highly sensitive cTn assays made the measurement of other markers (such as myoglobin, CK-MB mass, fatty acid binding protein) redundant, because they confer no added diagnostic benef...
This chapter outlines a series of analytical developments trending in POCT systems like miniaturization and parallelization. Focus will also be placed on the importance of smartphones for future applications, primarily in the personalized mHealth sector.
The implementation of POCT methods in the hospital is not solely a matter of negotiations between the clinical departments and the central laboratory. Over the long term, satisfactory solutions can only emerge when all participants in the POCT process also take part in the decision-making and in solving the problems and conflicts that occur. In ord...
The exclusion or early diagnosis of incipient nephropathy and urinary tract infections using qualitative test strip procedures are recognized as a domain of POCT. These and other procedures will be described in detail in this chapter. In contrast, the detection of fecal occult blood for colorectal cancer (CRC) screening will no longer be recommende...
The specificity of antibodies for their molecular antigen counterparts is the basis for immunoassay technology, which is also employed in POCT devices, enabling the synthesis of qualitative and quantitative results. Immunological POCT systems generally rely on electrochemical (potentiometric, amperometric, conductometric, capacitive) or optic senso...
This chapter defines the term “Point-of-Care Testing” (POCT) and explains its extensive areas of application.
This chapter explains the principles and applications of blood gas analysis methods that have been used successfully for many years at the point of care, while discussing the fundamentals and interpretation of disorders of acid-base balance.
This chapter systematically presents the non-invasive POCT methods currently available to date. Furthermore, it explains why long-demanded non-invasive analysis nevertheless rarely provides clinically evaluable results.
In the Third World, POCT plays an extremely important role in supplying the populations with laboratory medical tests. This chapter describes the preeminent problems within third-world healthcare systems and demonstrates how POCT can also be implemented sensibly within the scope of international development alliances.
This chapter explains the analytical principles incorporated into the POCT devices on the market. Furthermore, continuous monitoring methods are introduced that are already being used in patient care.
Zusammenfassung
Die Arbeitsgruppe POCT der Deutschen Gesellschaft für Klinische Chemie und Laboratoriumsmedizin (DGKL) hat vom 13. bis 15. März 2017 das dritte Münchner Symposium zum Thema „Weiterentwicklung der patientennahen Sofortdiagnostik in unterschiedlichen klinischen Anwendungsbereichen“ organisiert. Unter der Kongressleitung von Prof. Dr....
Chronic inflammation contributes to increased mortality in hemodialysis (HD) patients. YKL-40 is a novel marker of inflammation, tissue remodeling, and highly expressed in macrophages inside vascular lesions. Elevated levels of YKL-40 have been reported for HD patients but how it integrates into the proinflammatory mediator network as a predictor o...
Background:
In clinical chemistry, quality control (QC) often relies on measurements of control samples, and limitations, such as a lack of commutability, compromise the ability of such measurements to detect out-of-control situations. Medians of patient results have also been used for QC purposes, but it may be difficult to distinguish changes ob...
A novel therapeutic drug monitoring point of care testing (POCT) optical device for the detection of immunosuppressants in transplanted patients was designed and tested, with the body interface constituted by an intravascular microdialysis catheter (MicroEye®) which provides the dialysate as clinical sample. An optical biochip with 10 microchannels...
Background Some studies have already proposed an inverse association between vitamin D levels and breast density. As breast density is already considered an established risk factor for breast cancer, such a connection could offer a new starting point for the prevention of breast cancer.
Material and Methods To investigate this suggested connection,...
Background:
Therapeutic drug monitoring (TDM) of immunosuppressants is essential to optimize patient care after organ transplantation. In blood, most immunosuppressive drugs are bound to plasma proteins or located inside blood cells. However, it is generally assumed that only protein-unbound (free) drug concentrations are pharmacologically active...
Analysis of membrane proteins is still inadequately represented in diagnostics despite their importance as drug targets and biomarkers. One main reason is the difficult handling caused by their insolubility in aqueous buffer solutions. The nanodisc technology was developed to circumvent this challenge and enables analysis of membrane proteins with...
Die Labordiagnostik direkt am Krankenbett ist eine leistungsfähige Variante der Labormedizin, deren Entwicklung wesentlich durch die Miniaturisierung von Messgeräten und -verfahren sowie durch die Nutzung integrierter Informationstechniken begünstigt wird. Die gelegentlich zu beobachtende Polarisierung der Organisationsstruktur Zentrallabor vs. POC...
Nichtinvasive Analysemethoden werden schon seit langer Zeit für eine effektive Glukoseüberwachung beim Diabetiker gefordert. Eine schmerzfreie Analytik würde den diabetischen Menschen helfen, seine Glukosekonzentration häufiger oder sogar quasi kontinuierlich zu messen.
Auf dem IVD-Markt (IVD: In-vitro-Diagnostika) finden sich die unterschiedlichsten Geräte, von den kompakten »Handhelds« bis zu den Tischgeräten, die komplizierte Analysensysteme für Küvettentests oder trägergebundene Verfahren darstellen. Das Methodenspektrum reicht von einfachen Teststreifen bis hin zu komplexen immunchemischen Analysen. Die POCT-...
In den meisten Entwicklungsländern ist der Zugang der Bevölkerung zu einer besseren medizinischen Versorgung ein extrem dringliches Problem. Dabei sind die Strukturen der westlichen Gesundheitssysteme, z. B. mit großen Zentralkrankenhäusern, oft wenig hilfreich, sondern eine dezentrale Gesundheitsversorgung stellt meist einen effektiveren Ansatz da...
POCT wird bereits seit langem im Krankenhaus praktiziert. In Ermangelung von klaren Qualitätssicherungsvorgaben und in den Zeiten vor der DRGFallpauschalierung war die Art und Weise der Implementierung von POCT-Verfahren zunächst den klinischen Nutzern alleinig überlassen. Es wurden bei gleichzeitigem Bestehen eines Zentrallabors weder die verwende...
