Flow cytometry remains an indispensable part of the healthcare sector around the globe, and keeping track of wide-ranging consumer needs is fundamental for success in this field. In particular, ensuring user-friendliness, fluorescence capabilities, specialized research and clinical applications, and detection sensitivity are the most important factors influencing end-user purchase decisions and help solution providers widen their consumer base.

Consumer preferences shaping equipment adoption are - flow cytometry instrumentation that allows complementary approaches for diverse applications and immunophenotyping, the most popular research application for flow cytometry, closely followed by cell proliferation and cancer applications. Compared to the last decade the speed and accuracy of flow cytometers has increased. Previously, only a few samples could be analyzed for a certain period of time but nowadays, many samples can be analyzed simultaneously using this technology.

Multicolor flow cytometry. Researchers are demanding instruments with multiple light sources and different wavelengths in order to excite a greater range of colors and facilitate the rapid analysis of multiple samples. The increasing use of solid-state lasers, semiconductor lasers, and mercury lamps, in addition to traditionally preferred gas lasers, as light sources has propelled fluorescence as an important criterion for consumers. Multicolor flow cytometry rapidly reveals a large amount of biological information from a single sample.

Over the past few years, the number of parameters (and consequently colors) simultaneously analyzed in typical flow cytometry experiments has increased. This is enabled by the availability of high performance instrumentation with additional laser and detector options and data computational power, along with advances in biochemistry that have led to more fluorochrome options.

Complex analysis offered by flow cytometry has allowed analysis of various cell signaling and phenotypes of stem cells. This technology has the capabilities to conjugate antibodies to biomolecules, dyes, linkers, and drugs. Flow cytometer is also capable of measuring six markers and can produce 3 million data points from a single patient. Cell-based flow cytometry is commonly being used for measurement and diagnosis in blood cancer.

Small footprint. Small-sized, robust, and high-throughput flow cytometers designed for use in a number of clinical and research applications are witnessing significant demand among researchers. Flow cytometers are increasingly becoming compact and smaller yet more powerful to address the broad range of high-end needs of end-users. Improvements in fluorescent dyes and advent of technically advanced bench-top flow cytometers that offer the same performance and quality of high-end instruments represent other key growth drivers in the market.

Way Forward

The utility of flow cytometry has been limited by the challenge of standardizing instruments across facilities, companies, and geographies. The use of custom-manufactured fluorescent beads allows for greater consistency of intra- and inter-platform standardized setup, and provides a satisfactory basis for quantitative instrument standardization. This new approach has enabled comparable quantitative results to be generated by multiple flow cytometers at the same or different sites. The new method of intra- and inter-laboratory standardization of flow cytometry instruments allows instruments to produce data that shows very little variation from instrument to instrument for the same assays and sample types.

Another interesting area of development has been the ability to measure RNA levels by flow cytometry. There are several companies marketing products in this space - all of which will allow the ability to measure mRNA levels in a phenotypic manner.

Second Opinion
Technological Advancements Fuel Growth

The global flow cytometry market is poised to grow at a CAGR of 10 percent during 2013-18 and is expected to reach USD 3.7 billion by 2018. The Indian market is estimated to grow at the highest CAGR during the same period.

Technology trends and key growth drivers. The immunophenotypic identification and classification of cells by flow cytometry began in the early 1980s, with the revolution in immunology that brought about the discovery of T- and B-cells. This technology has now expanded to the analysis of other cells such as monocytes, macrophages, myeloid stem cells, tumor cells, and other cell types.

The flow cytometry market has experienced an explosive growth with increasing applications as a result of technological advancements in flow cytometry instruments and devices and the availability of high speed clinical grade cell sorters for clinical development and stem cell research. Technological advancements of easier-to-use flow cytometers for CD4 testing which can be used at the point-of-care integration of flow cytometry with multiplex imaging techniques and bead assays, and automated sample preparation and handling which enables high-throughput screening for drug discovery and development have also been instrumental in the increased use of this technique.

As other recent advancements, there has been the introduction of affordable, compact flow cytometry instruments with user-friendly software, shift of flow cytometry from research and core laboratories to individual laboratories and multi-color flow cytometers with multiple lasers that can detect a maximum number of cell parameters.

Challenges. Key factors restraining the growth of flow cytometry market include high instrument costs, lack of awareness among probable users, and the need for trained personnel. Because of the lack of awareness among clinicians about this technique and flow cytometry tests, there is also limited prescription of these tests in routine practice. Another major challenge is the short sample stability time of flow cytometry tests. More needs to be done to overcome this limitation.

Future outlook. The burgeoning healthcare market in India, in particular the diagnostics market and the pharmaceutical industry will help the flow cytometry market to grow. There is an increased demand for advanced technologies and, India, being a favoured healthcare destination in the Asia-Pacific region, there is a big scope for flow cytometry.

Dr Th Dhabali Singh
Managing Director,
Babina Diagnostics, Imphal

Second Opinion
HLA Antibody Screening

Hyperacute rejection in renal transplant recipients caused by pre-formed donor-specific human leucocyte antigen (HLA) antibodies (DSA) was first demonstrated by Patel and Terasaki. Since then it has been imperative to test all potential recipients prospectively for HLA antibodies.

Since early 1960s, serology-based complement-dependent cytotoxicity (CDC) assay has been the cornerstone technique for detection of HLA antibodies, not only in pre-transplant renal patients, but also in other forms of organ transplantation. In addition to this, sera can be tested against a panel of cells of known HLA types, and a panel reactive antibody (PRA), which is the percentage of cells in a random panel giving positive results with an antiserum, can be calculated.

Untill the late 1990s, a negative CDC crossmatch with no detectable DSA was considered suitable criteria for transplantation. Introduction of flow cytometry crossmatching changed perceptions with the discovery that this technique could detect donor-specific HLA antibodies, which in some cases was associated with rejection, even in the presence of a negative CDC crossmatch. In recent years, solid phase assays have been introduced as methods for HLA antibody screening, which have again redefined the definition of pre-sensitization.

These assays can be ELISA-based, where test sera is added to wells bearing specific HLA molecules, followed by addition of second enzyme linked anti-human IgG and substrate. The other technique involves using HLA antigen-coated beads used in a flow cytometry system or a Luminex platform, and is more sensitive than CDC for detecting both HLA class 1 and class 2 antibodies.

Dr (Prof.) R N Makroo
Director and Sr. Consultant,
Department of Transfusion Medicine, Molecular Biology & Transplant Immunology,
Indraprastha Apollo Hospitals


Flow cytometers, in which cells are analyzed as they flow through the apparatus in a fluid stream, can be equipped with sorting capability to allow separation of cells with preselected characteristics. However, when sorting is not required, an increasing proportion of the measurements now made in flow cytometers can be made in simpler, less expensive imaging systems. In future, improvements along this line should allow the benefits of cytometric technology to be applied to problems and in places for and in which it was previously unaffordable. Microbiologists, who have been among the have-nots with respect to cytometry, stand to benefit substantially from this.

Technological advancements such as the introduction of multicolor flow cytometers with multiple lasers have also fueled the uptake of flow cytometers. Factors such as increasing affordability, ease of use, and growth in reagent manufacturing have made flow cytometry instruments more accessible worldwide leading to increased adoption. Additionally, introduction of new reagents targeted at specific applications are driving growth in flow cytometry applications.

10 Diagnostic Imaging Trends for 2018



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