Clinical Laboratory Practice Research Articles

N-Acetylated Monosaccharides and Derived Glycan Structures Occurring in N- and O-Glycans During Prostate Cancer Development

Post-translational modifications of proteins play an important role in their stability, solubility and in vivo function. Also, for several reasons, such as the Golgi fragmentation during cancerogenesis, glycosylation as the most common modification is especially promising in offering high cancer specificity which, in combination with tissue-specific biomarkers available in the case of prostate diseases (PSA, PSMA, PAP), may lead to the development of novel oncodiagnostic approaches. In this review, we present the importance of subterminal glycan structures based on the N-acetylated monosaccharides GlcNAc and GalNAc in N- and also O-glycans, structures of which they are a component (LacNAc, LacdiNAc, branched structures). We also discuss the importance and clinical performance of these structures in cases of prostate cancer diagnostics using lectin-based affinity methods, which could be implemented in clinical laboratory practice in the future.

Strengthening the Application of the DAIDS GCLP Guidelines: The Implementation of an Integrated Laboratory Oversight Framework.

The Division of AIDS (DAIDS) Good Clinical Laboratory Practice (GCLP) Guidelines establish a framework to guide the oversight of laboratories supporting DAIDS-sponsored clinical research or trials. Compliance with these guidelines promotes data reliability, validity, and safety of the clinical research or trial participants and laboratory staff and ensures adherence to regulatory requirements. Acknowledgment and adoption of the DAIDS GCLP Guidelines are critical in building laboratory capacity and preparedness for conducting clinical trials. In collaboration with DAIDS, laboratory experts support the implementation of the DAIDS Integrated Laboratory Oversight Framework (Framework) activities. This article describes the implementation of the GCLP Guidelines, the Framework activities, and the coordinated efforts to strengthen laboratory performance. The Framework activities include four components: Quality Assurance Oversight, GCLP Audits, GCLP Training, and Laboratory Quality Improvement. Comparison of GCLP Guidelines with other regulations or standards, including U.S. Clinical Laboratory Improvement Amendments regulation 42 CFR 493, College of American Pathologists, World Health Organization GCLP, and International Organization for Standardization, ISO 15189:2012 standards, highlighted the differences and similarities to guide integration and harmonization efforts. Processes related to the Framework activities are outlined in detail, including key data derived from the managed activities of over 175 laboratories worldwide. Via the evolution of the DAIDS GCLP Guidelines and laboratory oversight workflows, the laboratories participating in DAIDS-sponsored clinical research and trials have successfully participated in internal and external regulatory audits. The collaborative and integrated oversight approach promotes knowledge-sharing and accountability to support the implementation of the DAIDS GCLP Guidelines and compliance monitoring. Lessons learned have helped with the implementation of the DAIDS integrated laboratory oversight approach and quality oversight programs at multiple laboratories worldwide.

Organisation of the Work of Bioanalytical Laboratories according to the Principles of Good Clinical Laboratory Practice (Review)

INTRODUCTION. Bioanalytical laboratories in the Russian Federation should follow the requirements of both the Good Laboratory Practices (GLP), when performing tests for non-clinical studies, and the Good Clinical Practices (GCP), when analysing samples from clinical studies. The work of such laboratories requires a separate GxP system, the Good Clinical Laboratory Practices (GCLP). However, the GCLP system has not yet been created in the Russian Federation and the Eurasian Economic Union (EAEU).АIM. This study aimed to compare the current Russian and EAEU principles regulating the work of bioanalytical laboratories with the international GCLP principles and formulate general requirements for national laboratories.DISCUSSION. The author analysed the current regulation of the work of bioanalytical laboratories, as well as the EAEU regulatory standards for the development and validation of analytical procedures. In addition, the study covered the international GCLP principles that govern the management of human resources, process record keeping, the development of standard operating procedures, the validation of analytical procedures, and the management of biological samples and reference standards in a laboratory. The author considered the key functions of a bioanalytical laboratory and suggested tools to manage them in compliance with the international GCLP principles and the EAEU requirements. It should be noted that scientific publications describe the international practice of applying the GCLP principles fairly well, and the experience of its implementation could be of use to Russian laboratories.CONCLUSION. A bioanalytical laboratory that implements the GCLP principles will increase its competitiveness in the EAEU market for bioanalytical testing services and mitigate its risks of obtaining invalid data.

Potential roles for artificial intelligence in clinical microbiology from improved diagnostic accuracy to solving the staffing crisis.

This review summarizes the current and potential uses of artificial intelligence (AI) in the current state of clinical microbiology with a focus on replacement of labor-intensive tasks. A search was conducted on PubMed using the key terms clinical microbiology and artificial intelligence. Studies were reviewed for relevance to clinical microbiology, current diagnostic techniques, and potential advantages of AI in routine microbiology workflows. Numerous studies highlight potential labor, as well as diagnostic accuracy, benefits to the implementation of AI for slide-based and macroscopic digital image analyses. These range from Gram stain interpretation to categorization and quantitation of culture growth. Artificial intelligence applications in clinical microbiology significantly enhance diagnostic accuracy and efficiency, offering promising solutions to labor-intensive tasks and staffing shortages. More research efforts and US Food and Drug Administration clearance are still required to fully incorporate these AI applications into routine clinical laboratory practices.

An Integrated DAIDS Laboratory Oversight Framework: Application of the DAIDS GCLP Guidelines.

The Division of AIDS (DAIDS) Good Clinical Laboratory Practice (GCLP) Guidelines establish a framework to guide the oversight of laboratories supporting DAIDS-sponsored clinical research or trials. Compliance with these guidelines promotes data reliability, consistency, and validity, and the safety of the clinical research or trial participants and laboratory staff, as well as ensures adherence to regulatory requirements. This article describes the application of the DAIDS GCLP Guidelines, the DAIDS Integrated Laboratory Oversight Framework, and the coordinated efforts of the collaborative oversight team of laboratory experts to support and monitor the performance of over 175 participating laboratories worldwide. Data from two self-administered online surveys conducted in 2017 and 2023 assessed the laboratory staff's experience implementing the GCLP Guidelines. The results of the 2017 survey were instrumental in informing changes to GCLP audit activities and promoting harmonization in the approach to laboratory oversight. A key finding from the 2023 survey results is the preference for hybrid GCLP training, encompassing face-to-face and online modules. Overall, both surveys acknowledged satisfaction with applying and implementing GCLP Guidelines. The need to effectively disseminate information about DAIDS laboratory oversight requirements to support the improved implementation of GCLP Guidelines was notable from both survey results. The collaborative team of laboratory experts and the integrated oversight approach promote knowledge-sharing and accountability to support the application of the GCLP Guidelines and compliance monitoring. The systematic implementation of the integrated laboratory oversight activities helped identify valuable lessons for improving laboratory performance and opportunities to strengthen quality oversight for laboratories participating in clinical research or trials.

TitrationAnalysis: a tool for high throughput binding kinetics data analysis for multiple label-free platforms

Label-free techniques including Surface Plasmon Resonance (SPR) and Biolayer Interferometry (BLI) are biophysical tools widely used to collect binding kinetics data of bimolecular interactions. To efficiently analyze SPR and BLI binding kinetics data, we have built a new high throughput analysis tool named the TitrationAnalysis. It can be used as a package in the Mathematica scripting environment and ultilize the non-linear curve-fitting module of Mathematica for its core function. This tool can fit the binding time course data and estimate association and dissociation rate constants (ka and kd respectively) for determining apparent dissociation constant (KD ) values. The high throughput fitting process is automatic, requires minimal knowledge on Mathematica scripting and can be applied to data from multiple label-free platforms. We demonstrate that the TitrationAnalysis is optimal to analyze antibody-antigen binding data acquired on Biacore T200 (SPR), Carterra LSA (SPR imaging) and ForteBio Octet Red384 (BLI) platforms. The ka , kd and KD values derived using TitrationAnalysis very closely matched the results from the commercial analysis software provided specifically for these instruments. Additionally, the TitrationAnalysis tool generates user-directed customizable results output that can be readily used in downstream Data Quality Control associated with Good Clinical Laboratory Practice operations. With the versatility in source of data input source and options of analysis result output, the TitrationAnalysis high throughput analysis tool offers investigators a powerful alternative in biomolecular interaction characterization.

Analytical performance evaluation of the Mindray enzymatic assay for hemoglobin A1c measurement

Hemoglobin A1c (HbA1c) plays a crucial role in diabetes management. We aimed to evaluate the analytical performance of a new enzymatic method kit for HbA1c measurement. The performance of the enzymatic method, including precision, accuracy, and linearity, was evaluated. Moreover, the interference effect from conventional interferents, Hb derivatives, Hb variants, and common drugs were assessed. In addition, the agreement of HbA1c results was compared between enzymatic methods, cation-exchange high-performance liquid chromatography (HPLC), and immunoassays. The intra-assay, between-assay, and total precision of HbA1c were all lower than 2%. HbA1c showed good linearity within the range of 3.96–20.23%. The enzymatic assay yielded results consistent with the external quality control samples, with a bias of less than ± 6% from the target values. The enzymatic method showed no interference from bilirubin, intralipid, vitamin C, Hb derivatives, common Hb variants, as well as antipyretic analgesics and hypoglycemic drugs. The HbA1c results of the enzymatic assay showed good agreement and accuracy compared to those obtained from the HPLC method and the immunoassay. The enzymatic method kit performed on the BS-600M chemistry analyzer is a reliable and robust method for measuring HbA1c. It is suitable for routine practice in clinical chemistry laboratories.

An up-conversion fluorescence lateral-flow immunoassay for rapid detection of Daratumumab in serum protein electrophoresis clinical samples

BackgroundDaratumumab (DARA) is a commonly used monoclonal antibody (mAb) drug for the treatment of multiple myeloma (MM). Its appearance as a visible abnormal band in the γ-region of a serum protein electrophoresis (SPEP) gel may interfere with the SPEP result interpretation. With the advantages of portability and rapid testing capabilities, up-conversion fluorescence lateral-flow immunoassay (LFA) can be an ideal solution to detect DARA interference. MethodsAn up-conversion fluorescence LFA strip was designed and constructed to perform semi-quantitative DARA testing in clinical samples. The LFA strip test was evaluated for limit of detection (LOD), dynamic range, and analytical interference. ResultsTo demonstrate the clinical utility of the LFA strip, 43 SPEP-positive patient serum samples were tested for the presence of DARA, and the results exactly matched the DARA usage history in patient medical records. ConclusionsThe performance of the up-conversion fluorescence LFA strip meets the purpose of clarifying DARA interference in SPEP results. It may be used as an independent and objective confirmation of the presence of DARA in clinical samples. The LFA strip offers a cost-effective rapid on-site test to check for DARA interference alongside standard SPEP equipment, which significantly improves the interpretation of ambiguous SPEP results involving DARA, and does not intervene the current SPEP workflow in clinical laboratory practice.

Simultaneous HPLC determination of remdesivir and dexamethasone in the presence of metformin, sitagliptin, and glimepiride in a synthetic mixture and spiked human plasma

The COVID-19 pandemic has raised many questions regarding the control and therapy of type 2 diabetes and the higher risk of severe disease progression. One of the therapeutic regimens used in moderate and severe cases of COVID-19, endorsed by the World Health Organization, involves the administration of an antiviral medicinal product and a corticosteroid. The present study describes the development of a liquid chromatographic method for the simultaneous separation and quantification of Remdesivir and Dexamethasone in the presence of Metformin, Sitagliptin, and Glimepiride in a synthetic mixture. The developed method also allows determination of Remdesivir, Dexamethasone, and Glimepiride in spiked plasma samples, using Sitagliptin as internal standard. A mixture of acetonitrile and potassium dihydrogen phosphate buffer (pH 3) in a ratio of 45:55 v/v was used as а mobile phase on a C18 column. The recovery percentages from plasma ranged from 85.1 to 108.5%. The developed method can serve in routine quality control and clinical laboratory practice.

Insights from semi-structured interviews on integrating artificial intelligence in clinical chemistry laboratory practices

BackgroundArtificial intelligence (AI) is gradually transforming the practises of healthcare providers. Over the last two decades, the advent of AI into numerous aspects of pathology has opened transformative possibilities in how we practise laboratory medicine. Objectives of this study were to explore how AI could impact the clinical practices of professionals working in Clinical Chemistry laboratories, while also identifying effective strategies in medical education to facilitate the required changes.MethodsFrom March to August 2022, an exploratory qualitative study was conducted at the Section of Clinical Chemistry, Department of Pathology and Laboratory Medicine, Aga Khan University, Karachi, Pakistan, in collaboration with Keele University, Newcastle, United Kingdom. Semi-structured interviews were conducted to collect information from diverse group of professionals working in Clinical Chemistry laboratories. All interviews were audio recorded and transcribed verbatim. They were asked what changes AI would involve in the laboratory, what resources would be necessary, and how medical education would assist them in adapting to the change. A content analysis was conducted, resulting in the development of codes and themes based on the analyzed data.ResultsThe interviews were analysed to identify three primary themes: perspectives and considerations for AI adoption, educational and curriculum adjustments, and implementation techniques. Although the use of diagnostic algorithms is currently limited in Pakistani Clinical Chemistry laboratories, the application of AI is expanding. All thirteen participants stated their reasons for being hesitant to use AI. Participants stressed the importance of critical aspects for effective AI deployment, the need of a collaborative integrative approach, and the need for constant horizon scanning to keep up with AI developments.ConclusionsThree primary themes related to AI adoption were identified: perspectives and considerations, educational and curriculum adjustments, and implementation techniques. The study’s findings give a sound foundation for making suggestions to clinical laboratories, scientific bodies, and national and international Clinical Chemistry and laboratory medicine organisations on how to manage pathologists’ shifting practises because of AI.

Evaluating the TaqMan Jra-Genotyping Method for Rapidly Predicting the Presence of Anti-Jra Antibodies.

The Jra antigen is a high-prevalence red blood cell (RBC) antigen. Reports on cases of fatal hemolytic disease of the fetus and newborn and acute hemolytic transfusion reactions suggest that antibodies against Jra (anti-Jra) have potential clinical significance. Identifying anti-Jra is challenging owing to a lack of commercially available antisera. We developed an alternative approach to rapidly predict the presence of anti-Jra using the TaqMan single-nucleotide polymorphism (SNP)-genotyping method. Residual peripheral blood samples from 10 patients suspected of having the anti-Jra were collected. Two samples with confirmed Jr(a-) RBCs and anti-Jra were used to validate the TaqMan genotyping assay by comparing the genotyping results with direct sequencing. The accuracy of the assay in predicting the presence of anti-Jra was verified through crossmatching with in-house Jr(a-) O+ RBCs. The TaqMan-genotyping method was validated with two Jr(a-) RBC- and anti-Jra-confirmed samples that showed concordant Jra genotyping and direct sequencing results. Jra genotyping for the remaining samples and crossmatching the serum samples with inhouse Jr(a-) O+ RBCs showed consistent results. We validated a rapid, simple, accurate, and cost-effective method for predicting the presence of anti-Jra using a TaqMan-based SNP-genotyping assay. Implementing this method in routine practice in clinical laboratories will assist in solving difficult problems regarding alloantibodies to high-prevalence RBC antigens and ultimately aid in providing safe and timely transfusions and proper patient care.

Kanamycin treated-ethylenediamine tetraacetic acid (EDTA)-dependent pseudothrombocytopenia in blood specimen of cats

Background: Pseudothrombocytopenia is a commonly obtained false negative result when analyzing feline platelet count by automated machine. It is related to ethylenediamine tetra-acetic acid (EDTA), a widely utilized anticoagulant in blood collection tube, resulting in EDTA-dependent pseudothrombocytopenia (EDTA-PTCP). Aim: To investigate whether treated with kanamycin enhanced the quantity of platelet aggregations in feline blood specimens collected using EDTA-PTCP. Methods: Thirty-one blood samples were obtained using EDTA tubes. The complete blood count was analyzed using automated Mindray-BC-5000Vet. Both Manual cell counts and thin blood smears were performed to estimate the amount of RBC, WBC and platelets as well as to evaluate the severity scores of platelet clumping, respectively. Comparisons were made between those pre-treated and treated with kanamycin in EDTA tube. Results: There were significantly different mean platelet counts in the samples before and after they were treated with kanamycin, both on automated (156.6  76.4 vs 260.3  115.5; p < 0.001) and manual (168.5  92.1 vs 262.8  119.6; p < 0.001) readings, with a 95% confidence interval (CI) of 0.19 (0.022–0.365). Conclusion: This study suggests that in clinical laboratory practice, kanamycin should be added to feline blood specimens with EDTA-PTCP.

HIV Infection and Potential Predisposing Risk Factors Among Brothel-Based and Non-Brothel-Based Female Sex Workers in Port Harcourt

The study comparatively evaluated the epidemiological distribution of HIV infection among brothel-based and non-brothelbased female sex workers in Port Harcourt. This cross-sectional study design employed venue/facility-based profiling and obtained unequal sample distribution, with more brothel-based, 108 (54%), compared to non-brothel-based, 92 (46%). Recruitment was through a multi-stage sampling with strict adherence to ethical guidelines and diagnostic protocol. The study followed standard clinical laboratory practices for HIV screening using HIV screening kit protocol. The study reported a general prevalence of 29 (14.5%), greater than the venue-specific prevalence among brothel FSWs (13.0%) but less than the prevalence among non-brothel-based FSWs (16.3%). Risk assessment showed no significance with an odd ratio of 1.308 (95% Confidence Interval = 0.595 to 2.877). There was also a relative risk of 1.139 (95% confidence interval = 0.763 to 1.699) and 0.871 (95% confidence interval = 0.590 to 1.284) for brothel-based female sex workers and non-brothel-based female sex workers, respectively. Despite the reported decline in HIV prevalence among FSWs in this study, the prevalence is still higher than the national prevalence in Nigeria. An enhanced expansion of HIV prevention intervention programs is crucial, even as the measure would help to curtail the trend among these high-risk populations.

VISCERAL MIGRATING LARVA. CLINICAL CASES. UKRAINIAN BURDEN

Introduction. The work highlights the problematic issues of diagnosis and treatment of toxocariasis infection in people in Ukraine, which become even more acute and urgent due to the migration of the population and animals, and the destruction of the country's infrastructure as a result of the war unleashed by Russia.
 The aim of the study. Improvement of aspects of clinical, laboratory and instrumental diagnostics, as well as treatment of VML in humans
 Materials and methods. A literature research of the state of the problem of primary and differential diagnosis of the migrating larva in Ukraine and the world has been conducted. 2 clinical cases of diagnosis and treatment of migrating larva in are described.
 Results. The article describes two clinical cases of visceral migrating larva. The differences of these cases, in addition to the migrating formations in the lungs, were the asymptomatic course, the absence of eosinophilia, and the simultaneous determination of blood class G antibodies by ELISA to Toxocar and human roundworm (A. lumbricoide), which persisted even after treatment. Patients at the stage of diagnosis were examined in an oncology hospital, were consulted by thoracic surgeons and oncologists to exclude lung cancer. Both women were immunocompetent, one patient had a history of cervical cancer. From the epidemiological anamnesis, both women kept cats, and one of them, during chemotherapy for the treatment of a tumor, had a propensity for carnivorous raw-eating. Before prescribing systemic antiparasitic chemotherapy, the patients were examined by an ophthalmologist to exclude parasitic chorioretinitis. The patients were prescribed a 20-day course of albendazal 800 mg/day in two doses. Support therapy consisted of a 5-day course of prednisolone at a dose of 30 mg/day orally in two doses, which started one day before the appointment of albendazole. A control CT scan of the lungs after therapy did not reveal any formations, fibrosis, or calcifications.
 Discussion. This case proves that tocoscarosis in humans is a multidisciplinary medical and social problem. Conclusions were made on the need to restore the national registration of the disease, adopt national consensuses on treatment and diagnosis, and implement into clinical practice modern methods of verification of specific antibodies to nematodes based on immunoblotting.
 Conclusions. The registration of cases of VML and T. in the system of control and prevention of infectious diseases in Ukraine should be resumed. It is expedient to introduce specific studies on nematodes in clinical laboratory practice.

Development of Simple HPLC-UV Method for the Simultaneous Determination of Repaglinide, Dexamethasone, and Remdesivir, and its Application to Synthetic Mixture and Human Plasma

Background:: The onset of the COVID-19 pandemic caused numerous difficulties in the treatment of cardiovascular diseases and diabetes mellitus. A persistent risk of developing severe complications and increased mortality from the COVID-19 infection has been reported. In the clinical studies, patients receiving remdesivir and dexamethasone as COVID-19 combination therapy simultaneously with some type II diabetes therapeutic regimens had been reported to have a considerably better state and recover faster. Unfortunately, there is not enough information on the combination of meglitinides, remdesivir, and dexamethasone, and therefore, careful monitoring of the patients' everyday health condition is needed. Objectives:: The present study aimed to describe a high-performance liquid chromatographic method for the determination of repaglinide, dexamethasone, and remdesivir in laboratoryprepared mixtures and human plasma by UV detection. Methods:: Isocratic elution of the mobile phase (consisting of 0.1% trifluoroacetic acid in water and acetonitrile in the ratio 70:30 v/v) was set at a flow rate of 1.0 ml/min, and the developed analytical procedure has been found to be fast and simple. Chromatographic determination was performed on a Purospher® RP – 18 column at room temperature and a UV detector was set at 235 nm. result: The developed method was validated for linearity in the range 2-32 μg/ml. Calibration curves were linear over the selected range with correlation coefficients (R2) greater than 0.996. The coefficients of variation for intraday and interday assay were <2% and the recovery percentages from plasma ranged from 93.83 to 106.49%. Conclusion:: The developed effective and specific method can be applied in routine quality control and clinical laboratory practice.

The history and evolution of HLA typing external proficiency testing schemes in UK NEQAS for H&I.

The UK National External Quality Assessment Service (NEQAS) provide an external proficiency testing (EPT) service for clinical laboratories. UK NEQAS for Histocompatibility and Immunogenetics (H&I) has been providing EPT schemes for over 45years and has grown during this time to provide 19 EPT schemes. Accurate human leucocyte antigen (HLA) typing is critical to support safe clinical services, including transplantation, therefore high quality, relevant EPT schemes are required as part of a laboratory's quality assurance. This article reviews the development of the HLA typing EPT schemes, from the first HLA phenotyping scheme in 1975, via the first HLA genotyping scheme in 1992, through to the introduction in 2017 of HLA third field assessment results from next-generation sequencing technology. In addition, the introduction of EPT schemes to cover HLA associated diseases and pharmacogenetic reactions, including HLA-B27, HLA*B*57:01 and HLA-DQ for coeliac disease are discussed. The accuracy of laboratory EPT results for HLA phenotyping are >96% (2018-2022), HLA genotyping >99% (2020-2022), HLA-B27 testing >99% (2018-2022) and B*57:01 testing >99% (2017-2022). However, for HLA genotyping for coeliac disease 22%-46% of laboratories made errors in 2020-2022. On investigation, the high rate of unsatisfactory performance was attributed to laboratories lacking specific knowledge to interpret HLA genotyping results and accurately report HLA types for coeliac disease. A misleading commercial kit insert was also identified. The assessment of scheme results has uncovered several issues which have been addressed with the intention of educating participants and improving clinical services. The UK NEQAS for H&I EPT schemes have evolved over the past four decades to reflect changes in HLA typing technology, laboratory clinical practice and to cover post-analytical interpretative elements of HLA typing.

Antimicrobial susceptibility testing and reporting practices of public hospital microbiology laboratories in Greece, 2022: A national observational survey and call for action.

Antimicrobial resistance (AMR) in Greece is among the highest across the European Union/European Economic Area (EU/EEA), with high AMR rates even to last-line antibiotics. To better understand the clinical microbiology laboratory practices and capacities in species identification and antimicrobial susceptibility testing (AST) across public healthcare establishments in Greece, we sent a questionnaire to 98 of 128 public hospital microbiology laboratories between 1 February and 1 April 2022. Of the 73.5% (72/98) that responded, 51.4% (37/72) reported using EUCAST guidelines. Two of three laboratories used an automated instrument for species identification and AST for all laboratory samples. Broth microdilution for colistin susceptibility testing was used by 46 of the laboratories, more frequently in larger (> 400 beds) versus smaller (< 400 beds) hospitals (90.5% (19/21) vs 52.9% (27/51) respectively, p = 0.011). MALDI-TOF mass spectrometry was available in one of 10 laboratories, and more often in larger compared to smaller hospitals (p = 0.035). Although the majority of laboratories had a laboratory information system (LIS) in place, only half had the capacity to extract data directly from the LIS for the purpose of AMR surveillance; 73.6% (53/72) used restrictive antibiograms. Public microbiology laboratory AMR capacities in Greece require improvement, prioritising interventions for EUCAST guidelines implementation.

Methods to Discover and Validate Biofluid-Based Biomarkers in Neurodegenerative Dementias

Neurodegenerative dementias are progressive diseases that cause neuronal network breakdown in different brain regions often because of accumulation of misfolded proteins in the brain extracellular matrix, such as amyloids or inside neurons or other cell types of the brain. Several diagnostic protein biomarkers in body fluids are being used and implemented, such as for Alzheimer’s disease. However, there is still a lack of biomarkers for co-pathologies and other causes of dementia. Such biofluid-based biomarkers enable precision medicine approaches for diagnosis and treatment, allow to learn more about underlying disease processes, and facilitate the development of patient inclusion and evaluation tools in clinical trials. When designing studies to discover novel biofluid-based biomarkers, choice of technology is an important starting point. But there are so many technologies to choose among. To address this, we here review the technologies that are currently available in research settings and, in some cases, in clinical laboratory practice. This presents a form of lexicon on each technology addressing its use in research and clinics, its strengths and limitations, and a future perspective.

Analytical and clinical validation of a blood progranulin ELISA in frontotemporal dementias.

Heterozygous mutations in the granulin (GRN) gene may result in haploinsufficiency of progranulin (PGRN), which might lead to frontotemporal dementia (FTD). In this study, we aimed to perform analytical and clinical validation of a commercial progranulin kit for clinical use. Analytical validation parameters including assay precision, selectivity, measurement range, dilution linearity, interferences and sample stability were tested according to previously described procedures. For clinical validation, PGRN levels were measured in plasma from 32 cognitively healthy individuals, 52 confirmed GRN mutation carriers, 25 C9orf72 mutation carriers and 216 patients with different neurodegenerative diseases of which 70 were confirmed as non-mutation carriers. Among the analytical validation parameters, assay precision and repeatability were very stable (coefficients of variation <7 %). Spike recovery was 96 %, the measurement range was 6.25-400 μg/L and dilution linearity ranged from 1:50-1:200. Hemolysis did not interfere with progranulin levels, and these were resistant to freeze/thaw cycles and storage at different temperatures. For the clinical validation, the assay was capable of distinguishing GRN mutation carriers from controls and non-GRN mutation carriers with very good sensitivity and specificity at a cut-off of 57 μg/L (97 %, 100 %, respectively). In this study, we demonstrate robust analytical and diagnostic performance of this commercial progranulin kit for implementation in clinical laboratory practice. This easy-to-use test allows identification of potential GRN mutation carriers, which may guide further evaluation of the patient. This assay might also be used to evaluate the effect of novel PGRN-targeting drugs and therapies.

TitrationAnalysis: a tool for high throughput binding kinetics data analysis for multiple label-free platforms.

Label-free techniques including Surface Plasmon Resonance (SPR) and Biolayer Interferometry (BLI) are biophysical tools widely used to collect binding kinetics data of bimolecular interactions. To efficiently analyze SPR and BLI binding kinetics data, we have built a new high throughput analysis tool named the TitrationAnalysis. It can be used as a package in the Mathematica scripting environment and ultilize the non-linear curve-fitting module of Mathematica for its core function. This tool can fit the binding time course data and estimate association and dissociation rate constants ( k a and k d respectively) for determining apparent dissociation constant ( K D) values. The high throughput fitting process is automatic, requires minimal knowledge on Mathematica scripting and can be applied to data from multiple label-free platforms. We demonstrate that the TitrationAnalysis is optimal to analyze antibody-antigen binding data acquired on Biacore T200 (SPR), Carterra LSA (SPR imaging) and ForteBio Octet Red384 (BLI) platforms. The k a, k d and K D values derived using TitrationAnalysis very closely matched the results from the commercial analysis software provided specifically for these instruments. Additionally, the TitrationAnalysis tool generates user-directed customizable results output that can be readily used in downstream Data Quality Control associated with Good Clinical Laboratory Practice operations. With the versatility in source of data input source and options of analysis result output, the TitrationAnalysis high throughput analysis tool offers investigators a powerful alternative in biomolecular interaction characterization.