A high-throughput technique to map cell images to cell positions using a 3D imaging flow cytometer.

We develop a high-throughput technique to relate positions of individual cells to their three-dimensional (3D) imaging features with single-cell resolution. The technique is particularly suitable for nonadherent cells where existing spatial biology methodologies relating cell properties to their positions in a solid tissue do not apply. Our design consists of two parts, as follows: recording 3D cell images at high throughput (500 to 1,000 cells/s) using a custom 3D imaging flow cytometer (3D-IFC) and dispensing cells in a first-in-first-out (FIFO) manner using a robotic cell placement platform (CPP). To prevent errors due to violations of the FIFO principle, we invented a method that uses marker beads and DNA sequencing software to detect errors. Experiments with human cancer cell lines demonstrate the feasibility of mapping 3D side scattering and fluorescent images, as well as two-dimensional (2D) transmission images of cells to their locations on the membrane filter for around 100,000 cells in less than 10 min. While the current work uses our specially designed 3D imaging flow cytometer to produce 3D cell images, our methodology can support other imaging modalities. The technology and method form a bridge between single-cell image analysis and single-cell molecular analysis.

Evaluation of analytical performance of AQUIOS CL flow cytometer and method comparison with bead-based flow cytometry methods.

OBJECTIVES: Given that method validation is mandatory for compliance with the International Organization for Standardization (ISO) 15,189 standard requirements, we evaluated the analytical performance of the AQUIOS CL system (Beckman Coulter) and compared it with two bead-based flow cytometry (FCM) protocols (BD FACSCAntoTM-II and Beckman Coulter DxFLEX). There are no comparative literature data on standardized protocols for counting lymphocyte subsets on the new-generation cytometer DxFLEX. METHODS: We evaluated the AQUIOS CL's performance with regard to accuracy, linearity and stability by using dedicated control cell samples and patient samples. We also compared the lymphocyte counts measured on the AQUIOS CL (n=69 samples) with those measured on the BD FACSCAntoTM-II and DxFLEX FCM systems. For 61 samples, FCM results were compared with those measured on the XN-3000 Sysmex hematology analyzer. RESULTS: AQUIOS CL showed acceptable performance - even outside the manufacturer's quantification ranges- and strong correlations with bead-based FCM methods. The FCM techniques and the XN-3000 gave similar absolute lymphocyte counts, although values in samples with intense lymphocytosis (B cell lymphoma/leukemia) were underestimated. CONCLUSIONS: The AQUIOS CL flow cytometer is a time-saving, single-platform system with good performance, especially when the manufacturer's instructions for use are followed. However, AQUIOS CL's possible limitations and pitfalls impose validation of a bead-based FCM method for immunophenotyping verification or as a back-up system. Although the DxFLEX flow cytometer is more time-consuming to use, it can provide standardized lymphocyte subset counts in case of aberrant results on AQUIOS CL or in the event of equipment failure.

Risk awareness during operation of analytical flow cytometers and implications throughout the COVID-19 pandemic.

The COVID-19 pandemic has brought biosafety to the forefront of many life sciences. The outbreak has compelled research institutions to re-evaluate biosafety practices and potential at-risk areas within research laboratories and more specifically within Shared Resource Laboratories (SRLs). In flow cytometry facilities, biological safety assessment encompasses known hazards based on the biological sample and associated risk group, as well as potential or unknown hazards, such as aerosol generation and instrument "failure modes." Cell sorting procedures undergo clearly defined biological safety assessments and adhere to well-established biosafety guidelines that help to protect SRL staff and users against aerosol exposure. Conversely, benchtop analyzers are considered low risk due to their low sample pressure and enclosed fluidic systems, although there is little empirical evidence to support this assumption of low risk. To investigate this, we evaluated several regions on analyzers using the Cyclex-d microsphere assay, a recently established method for cell sorter aerosol containment testing. We found that aerosol and/or droplet hazards were detected on all benchtop analyzers predominantly during operation in "failure modes." These results indicate that benchtop analytical cytometers present a more complicated set of risks than are commonly appreciated.

Solutions for Shared Resource Lab Remote Quality Control and Instrument Troubleshooting during a Pandemic.

The COVID-19 pandemic has dramatically affected shared resource lab (SRL) staff in-person availability at institutions globally. This article discusses the challenges of ensuring reliable instrument performance and quality data output while facility staff and external service provider on-site presence is severely limited. Solutions revolve around the adoption of remote monitoring and troubleshooting platforms, provision of self-service troubleshooting resources specific to facility instruments and workflows, development of an assistance contact policy, and ensuring efficiency of limited in-person staff time. These solutions employ software and hardware tools that are already in use or readily available in the SRL community, such as remote instrument access tools, video hosting and conferencing platforms, and ISAC shared resources. © 2020 International Society for Advancement of Cytometry.

Sub-micron picoplankton shape, orientation, and internal structure combined to preferentially amplify the forward scatter.

Compelling evidence is presented that sub-micron picoplankton shape, internal structure and orientation in combination leads to a disproportionate enhancement of differential forward scatter compared with differential side scatter when analyzed with a flow cytometer. Theoretical evidence is provided which results in an order of magnitude amplification in the forward scatter direction, with little or no change in the side scatter: this discounts the possibility of "doublets" caused by multiple particles simultaneously present in the laser beam. Observational evidence from progressively finer filtered seawater samples shows up to three orders of magnitude enhancement in the forward scatter direction and sizes of Prochlorococcus close to that reported in the literature (0.61 ± 0.17 µm). It therefore seems likely that flow cytometrically observed "bi-modal size distributions" of Prochlorococcus are instead the manifestation of intra-population differences in shape (spherical - prolate with preferential alignment) and internal structure (homogenous - heterogenous).

Residual red cells in blood components: A multisite study of fully automated enumeration using a hematology analyzer.

BACKGROUND: Manufacture of platelet concentrates (PCs) and plasma may fail to remove all residual red blood cells (rRBCs). Measuring rRBCs for compliance to guidelines has proven challenging, leading to an absence of a consensus methodology. Sysmex hematology analyzers with the Blood Bank mode (BB mode) analysis option offer the potential for automated rRBC counting. We therefore performed a two-site appraisal of the system. STUDY DESIGN AND METHODS: Performance characteristics were determined using platelet and plasma samples spiked with RBCs. Sample stability (n = 47) and the impact of sample type were also assessed. Components (platelets, n = 1474; plasma, n = 77) prepared using different routine manufacturing methods were tested to assess variation in rRBC concentration. RESULTS: Linearity studies up to 19 000 RBCs/µL demonstrated good correlation between expected and observed results (R2 ≥ 0.9731), and flow cytometric results also correlated well with BB mode (R2 = 0.9400). Precision analysis gave a limit of quantitation of 6 to 7 RBCs/µL, and carryover was 0.03%. Ethylenediaminetetraacetic acid and plain tube results were not significantly different (P ≥ 0.10), and samples were stable up to 24 hours. Apheresis PCs produced at two sites had lower rRBC concentrations (medians, 17 and 13 RBCs/µL) than those produced with the buffy coat method either manually (median, 681 RBCs/µL) or with the automated Terumo Automated Centrifuge and Separator Integration process (median, 81 RBCs/µL). All PCs failing visual inspection as having RBCs ≥4000 RBCs/µL were also detected by the BB mode. CONCLUSION: The BB mode had acceptable performance characteristics and has the potential for integration into a fully automated process control system for rRBC enumeration in plasma and PCs.

Comparative study of coelomocytes from Arbacia lixula and Lythechinus variegatus: Cell characterization and in vivo evidence of the physiological function of vibratile cells.

The knowledge on echinoderm coelomocytes has increased in recent years, but researchers still face a complex problem: how to obtain purified cells. Even flow cytometry being useful to address coelomocytes in suspension, the need for a method able to provide isolated cells is still noteworthy. Here, we use Imaging Flow Cytometry (IFC) to characterize the coelomocytes of two sea urchin species - Arbacia lixula and Lytechinus variegatus - and obtain gates to isolate cell populations. Then, we used these gates to study the physiological response of A. lixula coelomocytes during an induced immune challenge with Escherichia coli. An analysis of area and aspect ratio parameters of the flow cytometer allowed the identification of two main cell populations in the coelomic fluid: circular and elongated cells. A combination of this method with nucleus labeling using propidium iodide allowed the determination of gates containing isolated subpopulations of vibratile cells, red spherulocytes, and two phagocytes subpopulations in both species. We observed that during an induced bacterial immune challenge, A. lixula was able to modulate coelomocyte frequencies, increasing the phagocytes and decreasing red spherulocytes and vibratile cells. These results indicate that vibratile cells and red spherulocytes act by immobilizing and stoping bacterial growth, respectively, cooperating with phagocytes in the immune response. The use of IFC was fundamental not only to identify specific gates for the main coelomic subpopulations but also allowed the investigation on how echinoids modulate their physiological responses during immune challenges. Furthermore, we provide the first experimental evidence about the role of vibratile cells, corroborating its involvement with the immune system.

Cutting edge approaches for rapid characterization of airway exosomes.

Exosomes have been described as promising biomarkers for understanding disease progression and prognosis. These lipid membrane nanoparticles derived from airway cells have been shown to have immunomodulatory effects, such as driving inflammatory responses in asthma. These emerging evidences demonstrating an important pathophysiological role of exosomes warrants the development of novel approaches for isolation and rapid characterization of exosomes, which would be applicable for both translational and clinical studies. In this review article, we describe two methods of rapid exosomes characterization: (1) imaging flow cytometry using ImageStream; and (2) conventional flow cytometry using the BD Symphony A5 platform. We also explore sorting of exosomes using the BD Aria.

Evaluation of the sysmex UF-5000 fluorescence flow cytometer as a screening platform for ruling out urinary tract infections in elderly patients presenting at the Emergency Department.

In this study, we evaluated the performance of the flow cytometer-based Sysmex UF-5000 automated urine analyzer as a screening tool for ruling out urinary tract infections in elderly patients presenting at the emergency department. A total of 1119 unselected patient samples (including 544 samples from elderly patients) submitted for urine culture were included in this study. Samples were measured on UF-5000 and dipsticks and the results were compared with interpretation of culture results, which is the gold standard. We obtained a diagnostic sensitivity of 99% and specificity of 51% with a low rate of false negatives (0.2%) and a negative predictive value of 99% at 108 colony forming bacteria/L (CFB/L). A bacterial count ≥ 50x106/L or yeast like cells ≥ 25x106/L was used as the cutoff value. At this cutoff value, 30% of the urine cultures would have been redundant. This resulted in 35% false positive samples, mainly due to particle contamination or nongrowing bacteria. In comparison, at best, the dipsticks have a diagnostic sensitivity of 89%, a specificity of 52% and a negative predictive value of 92% at 108 CFB/L.

A performance comparison of the fully automated urine particle analyzer UF-5000 with UF-1000i and Gram staining in predicting bacterial growth patterns in women with uncomplicated urinary tract infections.

BACKGROUND: The aim of this study was to compare the performance of the new flow cytometer UF-5000 with the UF-1000i and Gram staining for determining bacterial patterns in urine samples. METHODS: Women who attended our clinic with symptoms suggestive of urinary tract infection were enrolled in the study. Mid-stream urine samples were collected for gram staining, urine analysis and urine cultures. Bacterial patterns were classified using the UF-1000i (none, cocci bacteria or rods/mixed growth), the UF-5000 (none, cocci, rods or mixed growth) and Gram staining. RESULTS: Among the 102 included samples, there were 10 g-positive cocci, 2 g-positive bacilli, 66 g-negative rods, and 24 mixed growth. The sensitivity/specificity of the UF-1000i was 81.8/91.1% for gram-negative rods and 23.5/96.9% for cocci/mixed. The sensitivity/specificity of the UF-5000 was 80.0/88.2% for gram negative rods and 70.0/86.5% for gram-positive cocci. CONCLUSIONS: The UF-5000 demonstrated good sensitivity and specificity for Gram-negative bacilli and demonstrated an improved sensitivity for detecting Gram-positive cocci compared with the UF-1000i.

Performance evaluation of leukocyte differential on the hematology analyzer Celltac G compared with two hematology analyzers, reference flow cytometry method, and two manual methods.

BACKGROUND: The automated hematology analyzer Celltac G (Nihon Kohden) was designed to improve leukocyte differential performance. Comparison with analyzers using different leukocyte detection principles and differential leukocyte count on wedge film (Wedge-Diff) shows its clinical utility, and comparison with immunophenotypic leukocyte differential reference method (FCM-Ref) shows its accuracy performance. METHODS: For method comparison, 598 clinical samples and 46 healthy volunteer samples were selected. The two comparative hematology analyzers (CAAs) used were XN-9000 (Sysmex) and CELL-DYN Sapphire (Abbott). The FCM-Ref provided by the Japanese Society for Laboratory Hematology was selected, and a flow cytometer Navios (Beckman-Coulter) was used. In manual differential, two kinds of automated slide makers were used: SP-10 (Sysmex) for wedge technique and SPINNER-2000 (Lion-Power) for spinner technique. The spinner technique avoids the issue of Wedge-Diff smudge cells by removing the risk of breaking cells and non-uniformity of blood cell distribution on films (Spinner-Diff). RESULTS: The Celltac G showed sufficient comparability (r = 0.67-1.00) with the CAAs for each leukocyte differential counting value at 0.00-40.87(109 /L), and sufficient comparability (r = 0.73-0.97) with FCM-Ref for each leukocyte differential percentage at 0.4-78.5. The identification ratio of the FCM-Ref in CD45-positive cells was 99.7% (99.4% to 99.8%). Differences were found between FCM-Ref/Celltac G/XN-9000/Spinner-Diff and Wedge-Diff for monocytes and neutrophils. The appearance ratio of smudge cells on wedge and spinner film was 12.5% and 0.5%. CONCLUSION: The Celltac G hematology analyzer's leukocyte differential showed adequate accuracy compared with the CAAs, FCM-Ref, and two manual methods and was considered suitable for clinical use.

Label-Free and Simultaneous Mechanical and Electrical Characterization of Single Plant Cells Using Microfluidic Impedance Flow Cytometry.

Despite that single-cell-type-level analyses have been extensively conducted on animal models to gain new insights into complex biological processes; the unique biological and physiological properties of plant cells have not been widely studied at single-cell resolution. In this work, an electrical impedance flow cytometry was fabricated based on microfluidics with constriction microchannel to simultaneously characterize the mechanical and electrical properties of single plant cells. Protoplasts from two model plant species, the herbaceous Arabidopsis thaliana and the woody Populus trichocarpa, could be readily discriminated by their respective mechanical traits, but not by electrical impedance. On the contrary, overexpression of a red fluorescent protein on plasma membrane resulted in changes in cell electrical impedance instead of cell deformability. During primary cell wall (PCW) regeneration, this extracellular layer outside of protoplasts introduced dramatic variations in both mechanical and electrical properties of single plant cells. Furthermore, the effects of auxin, an essential phytohormone regulating PCW reformation, were validated on this platform. Taken together, our results revealed a novel application of microfluidic impedance flow cytometry in the field of plant science to simultaneously characterize dual biophysical properties at single-cell resolution, which could be further developed as a powerful and reliable tool for plant cell phenotyping and cell fate specification.

Laborless, Automated Microfluidic Tandem Cell Processor for Visualizing Intracellular Molecules of Mammalian Cells.

Visualization and quantification of intracellular molecules of mammalian cells are crucial steps in clinical diagnosis, drug development, and basic biological research. However, conventional methods rely mostly on labor-intensive, centrifugation-based manual operations for exchanging the cell carrier medium and have limited reproducibility and recovery efficiency. Here we present a microfluidic cell processor that can perform four-step exchange of carrier medium, simply by introducing a cell suspension and fluid reagents into the device. The reaction time period for each reaction step, including fixation, membrane permeabilization, and staining, was tunable in the range of 2 to 15 min by adjusting the volume of the reaction tube connecting the neighboring exchanger modules. We double-stained the cell nucleus and cytoskeleton (F-actin) using the presented device with an overall reaction period of ∼30 min, achieving a high recovery ratio and high staining efficiency. Additionally, intracellular cytokine (IL-2) was visualized for T cells to demonstrate the feasibility of the device as a pretreatment system for downstream flow-cytometric analysis. The presented approach would facilitate the development of laborless, automated microfluidic systems that integrate cell processing and analysis operations and would pave a new path to high-throughput biological experiments.

Parallel single-cell optical transit dielectrophoresis cytometer.

In this work, we present an optical transit DEP flow cytometer for parallel single-cell analysis. Each cell's dielectric property is inferred from velocity perturbations due to DEP actuation in a microfluidic channel. Dual LED sources facilitate velocity measurement by producing two transit shadows for each cell passing through the channel. These shadows are detected using a 256-pixel linear optical array detector. Massively parallel analysis is possible as each pixel of the detector can independently analyze the passing cells. A wide channel (∼18 mm) was employed to carry many particles simultaneously, and the system was capable of detecting the velocity of over 200 cells simultaneously. We have achieved analysis rates for 10 µm diameter polystyrene spheres response exceeding 250 per second. With appropriate calibration, this DEP cytometer can quantitatively measure the dielectric response. The dielectric response (Clausius-Mossotti factor) of viable CHO cells was measured over the frequency range of 100 kHz to 6 MHz, and the obtained response matches the previously measured values by our group. The DEP cytometer uses simple modular components to achieve high throughput label-free single-cell dielectric analysis and can begin analyzing particles within 10 s after starting to pump the sample into the channel.

The use of a hematology analyzer with a new generation of software as an alternative to flow cytometry for enumerating residual white blood cells in blood components.

BACKGROUND: Leukoreduction of blood components was implemented to reduce transfusion-associated risks. The detection level for residual white blood cells (rWBCs) required to demonstrate leukoreduction was originally considered too low for hematology analyzers. Developments enabling cell counts in body fluids have, however, renewed interest in rWBC counting. An assessment of Sysmex XN hematology analyzers with software offering automated rWBC enumeration intended for use on blood components was performed. STUDY DESIGN AND METHODS: Performance characteristics were determined using platelet, red blood cell (RBC), and plasma samples spiked with WBCs. Subsequently, components (platelets, n = 1367; and plasma, n = 80) were tested and results compared with flow cytometry, to monitor leukoreduction efficiency to a level of less than 1 × 106 /unit. Components identified by flow cytometry as having poor leukoreduction, exceeding this limit, were also tested (platelets, n = 3; and RBCs, n = 10). RESULTS: Linearity studies up to 32 WBCs/µL showed good correlation between observed and expected results (R2 > 0.9996). Precision analysis gave an average limit of quantitation of 2 WBCs/µL with coefficients of variation less than 20%. Average carryover was 0.1%. Plain sample tubes were a source of aberrant results with routine components. Using ethylenediaminetetraacetic acid tubes the analyzer gave results greater than 1 × 106 /unit in 2.7% of cases compared with 1.4% by flow cytometry, but overall results were within specification, with more than 90% of components having rWBC values below the limit. All incidences of poor leukoreduction, with flow cytometry results greater than 13 rWBCs/µL were correctly identified, with an excellent correlation between results (R2 = 0.9818). CONCLUSION: The analyzer demonstrated acceptable performance characteristics for enumeration of rWBCs; consequently, additional multisite evaluations are warranted.

Development of a flow standard to enable highly reproducible measurements of deformability of stored red blood cells in a microfluidic device.

BACKGROUND: Great deformability allows red blood cells (RBCs) to flow through narrow capillaries in tissues. A number of microfluidic devices with capillary-like microchannels have been developed to monitor storage-related impairment of RBC deformability during blood banking operations. This proof-of-concept study describes a new method to standardize and improve reproducibility of the RBC deformability measurements using one of these devices. STUDY DESIGN AND METHODS: The rate of RBC flow through the microfluidic capillary network of the microvascular analyzer (MVA) device made of polydimethylsiloxane was measured to assess RBC deformability. A suspension of microbeads in a solution of glycerol in phosphate-buffered saline was developed to be used as an internal flow rate reference alongside RBC samples in the same device. RBC deformability and other in vitro quality markers were assessed weekly in six leukoreduced RBC concentrates (RCCs) dispersed in saline-adenine-glucose-mannitol additive solution and stored over 42 days at 4°C. RESULTS: The use of flow reference reduced device-to-device measurement variability from 10% to 2%. Repeated-measure analysis using the generalized estimating equation (GEE) method showed a significant monotonic decrease in relative RBC flow rate with storage from Week 0. By the end of storage, relative RBC flow rate decreased by 22 ± 6% on average. CONCLUSIONS: The suspension of microbeads was successfully used as a flow reference to increase reproducibility of RBC deformability measurements using the MVA. Deformability results suggest an early and late aging phase for stored RCCs, with significant decreases between successive weeks suggesting a highly sensitive measurement method.

Hydrodynamic flow cytometer performance enhancement by two-dimensional acoustic focusing.

Conventional flow cytometers employ hydrodynamic focusing method to insure detection accuracy by forcing cells go through detected position. However, an increased flow velocity will significantly reduce detection precision due to a fact that cells will deviate center position and are easily silted in choke point. In an effort to overcome this limitation, a two-dimension ultrasonic particle focusing method are presented in this work to enhance the performance of flow cytometer. Two piezoelectric transducers are used to attach to a 250 µm × 250 µm rectangular fused silica flow channel to realize the modification. Finite element model simulation is performed for parametrical analysis and simplifying experiment design. 3 µm polystyrene fluorescent particles are adopted to test focusing effect. One dimension acoustic focusing is achieved at 2.95 MHz with single focusing node as well as 2, 3, 4 nodes focusing near 6, 9, 12 MHz respectively. The 2D focusing particle stream width in two dimensions is less than 10 µm. Results verified that this method is applicable for Jurkat cells. Sample flow maintains its stability without clogging up even at high sample concentration. Focusing still works at flow velocity over 100 µl/min. All these results certify this acoustic particles focusing method can enhance the performance of hydrodynamic flow cytometer by minor modification.

Biosensing extracellular vesicles: contribution of biomolecules in affinity-based methods for detection and isolation.

Extracellular Vesicles (EVs) are lipid vesicles secreted by cells that allow intercellular communication. They are decorated with surface proteins, which are membrane proteins that can be targeted by biochemical techniques to isolate EVs from background particles. EVs have recently attracted attention for their potential applications as biomarkers for numerous diseases. This review focuses on the contribution of biomolecules used as ligands in affinity-based biosensors for the detection and isolation of EVs. Capturing biological objects like EVs with antibodies is well described in the literature through different biosensing techniques. However, since handling proteins can be challenging due to stability issues, sensors using non-denaturable biomolecules are emerging. DNA aptamers, short DNA fragments that mimic antibody action, are currently being developed and considered as the future of antibody-like ligands. These molecules offer undeniable advantages: unparalleled ease of production, very high stability in air, similar affinity constants to antibodies, and compatibility with many organic solvents. The use of peptides specific to EVs is also an exciting biochemical solution to target EV membrane proteins and complement other probes. These different ligands have been used in several types of biosensors: electrochemical, optical, microfluidic using both generic probes (targeting widely expressed membrane proteins such as the tetraspanins) and specific probes (targeting disease biomarkers such as proteins overexpressed in cancer).

A Beginner's Guide to Analyzing and Visualizing Mass Cytometry Data.

Mass cytometry has revolutionized the study of cellular and phenotypic diversity, significantly expanding the number of phenotypic and functional characteristics that can be measured at the single-cell level. This high-dimensional analysis platform has necessitated the development of new data analysis approaches. Many of these algorithms circumvent traditional approaches used in flow cytometric analysis, fundamentally changing the way these data are analyzed and interpreted. For the beginner, however, the large number of algorithms that have been developed, as well as the lack of consensus on best practices for analyzing these data, raise multiple questions: Which algorithm is the best for analyzing a dataset? How do different algorithms compare? How can one move beyond data visualization to gain new biological insights? In this article, we describe our experiences as recent adopters of mass cytometry. By analyzing a single dataset using five cytometry by time-of-flight analysis platforms (viSNE, SPADE, X-shift, PhenoGraph, and Citrus), we identify important considerations and challenges that users should be aware of when using these different methods and common and unique insights that can be revealed by these different methods. By providing annotated workflow and figures, these analyses present a practical guide for investigators analyzing high-dimensional datasets. In total, these analyses emphasize the benefits of integrating multiple cytometry by time-of-flight analysis algorithms to gain complementary insights into these high-dimensional datasets.

The genesis and evolution of bead-based multiplexing.

Multiplexed analysis has the advantage of allowing for simultaneous detection of multiple analytes in a single reaction vessel which reduces time, labor, and cost as compared to single-reaction-based detection methods. Microsphere-based suspension array technologies, such as the Luminex® xMAP® system, offer high-throughput detection of both protein and nucleic acid targets in multiple assay chemistries. After Luminex's founding in 1995, it quickly became the leader in bead-based multiplexing solutions. Today, xMAP Technology is the most widely adopted bead-based multiplexing platform with over 35,000 peer-reviewed publications, an installed base of approximately 15,500 instruments, and over 70 Luminex Partners offering more than 1300 research use kits as well as custom assay solutions. Because of the open architecture of the xMAP platform it has been implemented in a variety of applications that range from transplant medicine, biomarker discovery and validation, pathogen detection, drug discovery, vaccine development, personalized medicine, neurodegeneration, and cancer research.