Clinical Chemistry Laboratory Automation in the 21st Century - Amat Victoria curam (Victory loves careful preparation)

The era of automation arrived with the introduction of the AutoAnalyzer using continuous flow analysis and the Robot Chemist that automated the traditional manual analytical steps. Successive generations of stand-alone analysers increased analytical speed, offered the ability to test high volumes of patient specimens, and provided large assay menus. A dichotomy developed, with a group of analysers devoted to performing routine clinical chemistry tests and another group dedicated to performing immunoassays using a variety of methodologies. Development of integrated systems greatly improved the analytical phase of clinical laboratory testing and further automation was developed for pre-analytical procedures, such as sample identification, sorting, and centrifugation, and post-analytical procedures, such as specimen storage and archiving. All phases of testing were ultimately combined in total laboratory automation (TLA) through which all modules involved are physically linked by some kind of track system, moving samples through the process from beginning-to-end. A newer and very powerful, analytical methodology is liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS). LC-MS/MS has been automated but a future automation challenge will be to incorporate LC-MS/MS into TLA configurations. Another important facet of automation is informatics, including middleware, which interfaces the analyser software to a laboratory information systems (LIS) and/or hospital information systems (HIS). This software includes control of the overall operation of a TLA configuration and combines analytical results with patient demographic information to provide additional clinically useful information. This review describes automation relevant to clinical chemistry, but it must be recognised that automation applies to other specialties in the laboratory, e.g. haematology, urinalysis, microbiology. It is a given that automation will continue to evolve in the clinical laboratory, limited only by the imagination and ingenuity of laboratory scientists.     

Considerations for Group Testing: A Practical Approach for the Clinical Laboratory

Group testing, also known as pooled sample testing, was first proposed by Robert Dorfman in 1943. While sample pooling has been widely practiced in blood-banking, it is traditionally seen as anathema for clinical laboratories. However, the ongoing COVID-19 pandemic has re-ignited interest for group testing among clinical laboratories to mitigate supply shortages. We propose five criteria to assess the suitability of an analyte for pooled sample testing in general and outline a practical approach that a clinical laboratory may use to implement pooled testing for SARS-CoV-2 PCR testing. The five criteria we propose are: (1) the analyte concentrations in the diseased persons should be at least one order of magnitude (10 times) higher than in healthy persons; (2) sample dilution should not overly reduce clinical sensitivity; (3) the current prevalence must be sufficiently low for the number of samples pooled for the specific protocol; (4) there is no requirement for a fast turnaround time; and (5) there is an imperative need for resource rationing to maximise public health outcomes. The five key steps we suggest for a successful implementation are: (1) determination of when pooling takes place (pre-pre analytical, pre-analytical, analytical); (2) validation of the pooling protocol; (3) ensuring an adequate infrastructure and archival system; (4) configuration of the laboratory information system; and (5) staff training. While pool testing is not a panacea to overcome reagent shortage, it may allow broader access to testing but at the cost of reduction in sensitivity and increased turnaround time.     

Pre-analytical factors affecting the results of laboratory blood analyses in farm animal veterinary diagnostics

The quality of the laboratory diagnostic approach in farm animals can be severely affected by pre-analytical factors of variation. They induce increase/decrease of biochemical and hematological analyte concentrations and, as a consequence, they may cause unsuitable conclusions and decisions for animal health management and research projects. The pre-analytical period covers the preparation of sampling, the sampling procedure itself, as well as all specimen handling until the beginning of the specific laboratory analysis. Pre-analytical factors may have either an animal-related or a technique-related background. Animal-related factors cover daytime/season, meals/fasting, age, gender, altitude, drugs/anesthesia, physical exercise/stress or coinfection. Technique-related factors are the choice of the tube including serum v. plasma, effects of anticoagulants/gel separators, the anticoagulant/blood ratio, the blood collection procedure itself, specimen handling, contamination, labeling, storage and serum/plasma separation, transportation of the specimen, as well as sample preparation before analysis in the laboratory. It is essential to have proper knowledge about the importance and source of pre-analytical factors to alter the entire diagnostic process. Utmost efforts should be made to minimize controllable factors. Analytical results have to be evaluated with care considering that pre-analytical factors of variation are possible causes of misinterpretation.     

Dried Blood Spots - Preparing and Processing for Use in Immunoassays and in Molecular Techniques

The idea of collecting blood on a paper card and subsequently using the dried blood spots (DBS) for diagnostic purposes originated a century ago. Since then, DBS testing for decades has remained predominantly focused on the diagnosis of infectious diseases especially in resource-limited settings or the systematic screening of newborns for inherited metabolic disorders and only recently have a variety of new and innovative DBS applications begun to emerge. For many years, pre-analytical variables were only inappropriately considered in the field of DBS testing and even today, with the exception of newborn screening, the entire pre-analytical phase, which comprises the preparation and processing of DBS for their final analysis has not been standardized. Given this background, a comprehensive step-by-step protocol, which covers al the essential phases, is proposed, i.e., collection of blood; preparation of blood spots; drying of blood spots; storage and transportation of DBS; elution of DBS, and finally analyses of DBS eluates. The effectiveness of this protocol was first evaluated with 1,762 coupled serum/DBS pairs for detecting markers of hepatitis B virus, hepatitis C virus, and human immunodeficiency virus infections on an automated analytical platform. In a second step, the protocol was utilized during a pilot study, which was conducted on active drug users in the German cities of Berlin and Essen.     

Standard operating procedures for pre-analytical handling of blood and urine for metabolomic studies and biobanks

(1)H NMR metabolic profiling of urine, serum and plasma has been used to monitor the impact of the pre-analytical steps on the sample quality and stability in order to propose standard operating procedures (SOPs) for deposition in biobanks. We analyzed the quality of serum and plasma samples as a function of the elapsed time (t?=?0-4?h) between blood collection and processing and of the time from processing to freezing (up to 24?h). The stability of the urine metabolic profile over time (up to 24?h) at various storage temperatures was monitored as a function of the different pre-analytical treatments like pre-storage centrifugation, filtration, and addition of the bacteriostatic preservative sodium azide. Appreciable changes in the profiles, reflecting changes in the concentration of a number of metabolites, were detected and discussed in terms of chemical and enzymatic reactions for both blood and urine samples. Appropriate procedures for blood derivatives collection and urine preservation/storage that allow maintaining as much as possible the original metabolic profile of the fresh samples emerge, and are proposed as SOPs for biobanking.     

Red cell PMVs, plasma membrane-derived vesicles calling out for standards

Plasma membrane-derived vesicles (PMVs) or microparticles are vesicles (0.1-1 μm in diameter) released from the plasma membrane of all blood cell types under a variety of biochemical and pathological conditions. PMVs contain cytoskeletal elements and some surface markers from the parent cell but lack a nucleus and are unable to synthesise macromolecules. They are also defined on the basis that in most cases PMVs express varying amounts of the cytosolic leaflet lipid phosphatidylserine, which is externalised during activation on their surface. This marks the PMV as a biologically distinct entity from that of its parent cell, despite containing surface markers from the original cell, and also explains its role in events such as phagocytosis and thrombosis. There is currently a large amount of variation between investigators with regard to the pre-analytical steps employed in isolating red cell PMVs or RPMVs (which are slightly smaller than most PMVs), with key differences being centrifugation and sample storage conditions, which often leads to result variability. Unfortunately, standardization of preparation and detection methods has not yet been achieved. This review highlights and critically discusses the variables contributing to differences in results obtained by investigators, bringing to light numerous studies of which RPMVs have been analysed but have not yet been the subject of a review.     

Use of ion trap gas chromatography-multiple mass spectrometry for the detection and confirmation of 3'hydroxystanozolol at trace levels in urine for doping control

Stanozolol, a synthetic anabolic androgenic steroid, is often abused in sports to enhance performance. Consequently, the anti-doping laboratories daily screen for its metabolites (3'hydroxystanozolol and 4beta hydroxystanozolol) in all urines, mainly by GC-MS, after enzymatic hydrolysis and TMS derivatization. A sensitive and specific method by GC-MS(3) has been developed for the identification in urine of 3'hydroxystanozolol at trace levels. Full mass spectra and diagnostic ions are presented and a case report is commented. In this case, it was possible to attest the presence of a low concentration of stanozolol metabolite in a sample obtained from a competition test. This would have not been possible with other analytical techniques used in the laboratory. Through this case report, it was also possible to demonstrate the importance of sampling and the difficulties that has to face the laboratory when the pre-analytical step is not correctly performed.     

HUPO Plasma Proteome Project specimen collection and handling: towards the standardization of parameters for plasma proteome samples

There is a substantial list of pre-analytical variables that can alter the analysis of blood-derived samples. We have undertaken studies on some of these issues including choice of sample type, stability during storage, use of protease inhibitors, and clinical standardization. As there is a wide range of sample variables and a broad spectrum of analytical techniques in the HUPO PPP effort, it is not possible to define a single list of pre-analytical standards for samples or their processing. We present here a compendium of observations, drawing on actual results and sound clinical theories and practices. Based on our data, we find that (1) platelet-depleted plasma is preferable to serum for certain peptidomic studies; (2) samples should be aliquoted and stored preferably in liquid nitrogen; (3) the addition of protease inhibitors is recommended, but should be incorporated early and used judiciously, as some form non specific protein adducts and others interfere with peptide studies. Further, (4) the diligent tracking of pre-analytical variables and (5) the use of reference materials for quality control and quality assurance, are recommended. These findings help provide guidance on sample handling issues, with the overall suggestion being to be conscious of all possible pre-analytical variables as a prerequisite of any proteomic study.     

Optimised Pre-Analytical Methods Improve KRAS Mutation Detection in Circulating Tumour DNA (ctDNA) from Patients with Non-Small Cell Lung Cancer (NSCLC)

Introduction

Non-invasive mutation testing using circulating tumour DNA (ctDNA) is an attractive premise. This could enable patients without available tumour sample to access more treatment options.

Materials & Methods

Peripheral blood and matched tumours were analysed from 45 NSCLC patients. We investigated the impact of pre-analytical variables on DNA yield and/or KRAS mutation detection: sample collection tube type, incubation time, centrifugation steps, plasma input volume and DNA extraction kits.

Results

2 hr incubation time and double plasma centrifugation (2000 x g) reduced overall DNA yield resulting in lowered levels of contaminating genomic DNA (gDNA). Reduced “contamination” and increased KRAS mutation detection was observed using cell-free DNA Blood Collection Tubes (cfDNA BCT) (Streck), after 72 hrs following blood draw compared to EDTA tubes. Plasma input volume and use of different DNA extraction kits impacted DNA yield.

Conclusion

This study demonstrated that successful ctDNA recovery for mutation detection in NSCLC is dependent on pre-analytical steps. Development of standardised methods for the detection of KRAS mutations from ctDNA specimens is recommended to minimise the impact of pre-analytical steps on mutation detection rates. Where rapid sample processing is not possible the use of cfDNA BCT tubes would be advantageous.     

Pre-analytical issues for testosterone and estradiol assays

In order to standardize and harmonize testosterone measurement, it is vital to identify and minimize pre-analytical error as well as standardize them when developing reference intervals. These pre-analytic issues can be separated into technical and biological factors. Technical factors to address are the type of sample (serum vs. plasma), the type of collection tube, and the processing, storage, and handling of the samples. Biological issues include addressing the age of the subject, the time of day and month the sample is drawn, and all of the possible interfering drugs the subject may be taking. We recommend that great attention be paid to these pre-analytical issues before the assay methodologies are harmonized.     

Renal cell carcinoma: handling and treatment

The quality of samples and of pre-analytical steps are crucial in all biological tests, this is dramatically true in proteomics analysis. In renal cell carcinoma preparation for two-dimensional gel electrophoresis the time elapsed between sample collection and treatment, and the heterogeneity of tissues are considered in order to obtain high quality and reproducibility of spots. The mechanical dissection and cell separation by magnetic beads coated with anti-Ber and EP4 antibodies to minimize the contamination of nonepithelial cells are described.     

Clinical biochemistry in sheep: A selected review

As in other species, the first point in sheep clinical biochemistry is the correct selection of the appropriate tests and, consequently, the optimal management of the pre-analytical phase from the collection of the samples to their management and possible transport or storage before analysis. There are so many different breeds and breeding systems in sheep, as well as laboratory techniques, that no universally acceptable reference values and ranges can be provided. Each laboratory should determine its own reference values and ranges, according to recommended methods. The main uses of clinical biochemistry in sheep health management are in the diagnosis of liver, muscle and nutritional disorders, for which selected examples are discussed in this paper.     

Portable cell-based biosensor system using integrated CMOS cell-cartridges.

The use of cell-based biosensors outside of the laboratory has been limited due to many issues including preparation of the sample, maintenance of the biological environment, and integration of the electronics for data collection and analysis. This paper describes a system that addresses several of these issues with the development of an integrated silicon-polydimethylsiloxane cell-cartridge. The cell-cartridge contains a CMOS silicon chip that incorporates a digital interface, temperature control system, microelectrode electrophysiology sensors, and analog signal buffering. Additionally, the cell-cartridge supports two separate cell populations in two 10 microl sealed chambers that have independent fluidic channels for sample injection. A portable, microcontroller-based electronics system capable of monitoring the action potential (AP) activity within the cell-cartridges was also developed. The AP activities of cardiomyocyte syncytia in the two chambers differentially responded to the flow of a control medium versus the flow of a biochemical agent. The cell-cartridges and portable electronics system were used to successfully record AP activity from cardiomyocytes outside of the laboratory under realistic application conditions.     

Quality control issues in point of care testing

* Quality Control (QC) in Point of Care Testing (PoCT) is often thought of as a complex issue; however intelligent system analysis can simplify matters and greatly increase the chances of a well controlled system. What we want to achieve is a QC program which adequately controls the PoCT system, but does not excessively contribute to the operating costs or complexity of maintaining a PoCT instrument, or network of instruments. * Don't neglect effective pre-analytical work: good documentation, operator training, monitoring, and analyser maintenance programs are essential, as for any analyser. * Look closely at your analyser: Is it a "laboratory type" instrument or cartridge or strip based? Can it perform multiple test types or a single test only? How is it calibrated? Does it have built in self-check capabilities or an electronic check cartridge? Is the sample in contact with the instrument? What are the cartridge/strip/reagent storage requirements? * Establish where the analysis is taking place and which system component is involved. * Tailor your QC program to target this component, but still check the system as a whole. * A common approach is to check cartridges/strips on delivery and run a QA sample at least monthly to check storage conditions and operator performance. If there is no independent electronic instrument check, daily QC checks are also recommended. * Don't be afraid to stray beyond conventional QC models if necessary. Some PoCT systems are not adequately controlled by the application of conventional QC alone.     

Unravelling in vitro variables of major importance for the outcome of mass spectrometry-based serum proteomics

The use of mass spectrometry (MS) for analysing low-molecular weight proteins and peptides from biological fluids has a great, yet not fully realized, potential for biomarker discovery. To prune MS-data as much as possible for non-relevant non-biological variation the development of standardized protocols for handling and processing the samples before MS and adjusting data after MS to compensate for method-induced variability are warranted. This calls for knowledge about how different variables contribute to MS-based proteome analyses. In addition, identification of the peptides involved in pre-analytical variation will be helpful in evaluating the clinical significance of predictive models derived from MS data. Using human sera, extraction by weak cation-exchange magnetic beads, and analysis by MALDI-TOF MS we here evaluated pre-analytical variation and identify peptides involved in this. The influences of humidity, temperature, and time for preparation of sera on spectral changes were evaluated. Also, the reproducibility of the methods and the effect of a baseline correction procedure were examined. Low temperatures, short handling times, and a baseline correction procedure minimize the contribution of artifacts to sample variability as observed by MS. The complement split product C3f and fragments thereof appear to be sensitive indicators of sample handling induced modifications. Other peptides that are indicative of such variability are fibrin and kininogen fragments. Using strict experimental guidelines as well as standardized sample collection procedures it is possible to obtain reproducible peak intensities and positions in serum mass profiling using magnetic bead-based fractionation and MALDI-TOF MS.     

From Benchtop to Desktop: Important Considerations when Designing Amplicon Sequencing Workflows

Amplicon sequencing has been the method of choice in many high-throughput DNA sequencing (HTS) applications. To date there has been a heavy focus on the means by which to analyse the burgeoning amount of data afforded by HTS. In contrast, there has been a distinct lack of attention paid to considerations surrounding the importance of sample preparation and the fidelity of library generation. No amount of high-end bioinformatics can compensate for poorly prepared samples and it is therefore imperative that careful attention is given to sample preparation and library generation within workflows, especially those involving multiple PCR steps. This paper redresses this imbalance by focusing on aspects pertaining to the benchtop within typical amplicon workflows: sample screening, the target region, and library generation. Empirical data is provided to illustrate the scope of the problem. Lastly, the impact of various data analysis parameters is also investigated in the context of how the data was initially generated. It is hoped this paper may serve to highlight the importance of pre-analysis workflows in achieving meaningful, future-proof data that can be analysed appropriately. As amplicon sequencing gains traction in a variety of diagnostic applications from forensics to environmental DNA (eDNA) it is paramount workflows and analytics are both fit for purpose.     

Pre-Analytical Sample Quality: Metabolite Ratios as an Intrinsic Marker for Prolonged Room Temperature Exposure of Serum Samples

Advances in the “omics” field bring about the need for a high number of good quality samples. Many omics studies take advantage of biobanked samples to meet this need. Most of the laboratory errors occur in the pre-analytical phase. Therefore evidence-based standard operating procedures for the pre-analytical phase as well as markers to distinguish between ‘good’ and ‘bad’ quality samples taking into account the desired downstream analysis are urgently needed. We studied concentration changes of metabolites in serum samples due to pre-storage handling conditions as well as due to repeated freeze-thaw cycles. We collected fasting serum samples and subjected aliquots to up to four freeze-thaw cycles and to pre-storage handling delays of 12, 24 and 36 hours at room temperature (RT) and on wet and dry ice. For each treated aliquot, we quantified 127 metabolites through a targeted metabolomics approach. We found a clear signature of degradation in samples kept at RT. Storage on wet ice led to less pronounced concentration changes. 24 metabolites showed significant concentration changes at RT. In 22 of these, changes were already visible after only 12 hours of storage delay. Especially pronounced were increases in lysophosphatidylcholines and decreases in phosphatidylcholines. We showed that the ratio between the concentrations of these molecule classes could serve as a measure to distinguish between ‘good’ and ‘bad’ quality samples in our study. In contrast, we found quite stable metabolite concentrations during up to four freeze-thaw cycles. We concluded that pre-analytical RT handling of serum samples should be strictly avoided and serum samples should always be handled on wet ice or in cooling devices after centrifugation. Moreover, serum samples should be frozen at or below -80°C as soon as possible after centrifugation.     

Direct quantification of dimethylsulfoniopropionate (DMSP) with hydrophilic interaction liquid chromatography/mass spectrometry

A simple, derivatization free method for the direct determination of dimethylsulfoniopropionate (DMSP) using hydrophilic interaction liquid chromatography (HILIC)/mass spectrometry is introduced. DMSP is a zwitterionic osmolyte which is produced from marine plankton, macro algae and higher plants. Due to its central role in climate relevant geochemical processes as well as in plant physiology and chemical ecology there is a great interest in methods for its quantification. Since DMSP is labile and difficult to extract currently most protocols for quantification are based on indirect methods. Here we show that ultra performance liquid chromatography/mass spectrometry using a HILIC stationary phase is suitable for the direct quantification of DMSP from aqueous samples and microalgal extracts. The protocol requires minimal sample preparation and phytoplankton samples can be investigated after filtration of small volumes. The limit of detection is 20nM and the calibration curve is linear in the range of 60nM to 50μM. The use of [(2)H(6)]-DMSP as internal standard allows prolonged sample storage since it is transformed with the same kinetics as natural DMSP. This makes the method suitable for both laboratory and field studies.     

Quantitative assessment of anthrax vaccine immunogenicity using the dried blood spot matrix

The collection, processing and transportation to a testing laboratory of large numbers of clinical samples during an emergency response situation present significant cost and logistical issues. Blood and serum are common clinical samples for diagnosis of disease. Serum preparation requires significant on-site equipment and facilities for immediate processing and cold storage, and significant costs for cold-chain transport to testing facilities. The dried blood spot (DBS) matrix offers an alternative to serum for rapid and efficient sample collection with fewer on-site equipment requirements and considerably lower storage and transport costs. We have developed and validated assay methods for using DBS in the quantitative anti-protective antigen IgG enzyme-linked immunosorbent assay (ELISA), one of the primary assays for assessing immunogenicity of anthrax vaccine and for confirmatory diagnosis of Bacillus anthracis infection in humans. We have also developed and validated high-throughput data analysis software to facilitate data handling for large clinical trials and emergency response.     

Carbamylation of proteins in 2-D electrophoresis--myth or reality?

Carbamylation is widely quoted as being a problem in 2-D gel analysis and the associated sample preparation steps. This modification occurs when iso-cyanate, a urea break-down product, covalently modifies lysine residues, thus inducing a change in isoelectric point. Urea is used at up to 9 M concentrations in sample preparation and 2-D gels because of its ability to disrupt protein structure and effect denaturation without the need for ionic surfactants such as SDS. We have studied carbamylation using 7 M urea and 2 M thiourea, under a range of experimental temperatures to establish when, and if, it occurs and what can be done to minimize the modification. The actual time required for protein extraction from a tissue is usually short compared to the time required for procedures such as reduction and alkylation and IPG rehydration and focusing. Therefore, it is the temperature during these post-extraction procedures that is the most critical factor. Our experiments have shown that carbamylation does not occur during electrophoresis in the presence of urea, even with prolonged run-times. However, under poorly controlled sample preparation and storage conditions, it can become a major event.