Off-the-shelf flow cytometry testing can enable smaller hematology laboratories to maximize their workforce capacity, save time and money, and achieve faster, more detailed and more accurate immunophenotyping for their clients, according to international experts in this increasingly important field of hematological study.

Flow cytometry is a powerful tool used in immunophenotyping for hematological malignancies, such as chronic lymphocytic leukemia (CLL), as well as in basic research and in clinical trials. Flow cytometry is held to have several advantages over immunohistochemistry (IHC) in cancer including: the ability to define distinct cell populations by their size and granularity; the capacity to gate out dead cells detection of weakly expressed surface antigens; and multi-colour analysis to measure several antigens simultaneously. At the heart of the test is a panel of antibodies that detect markers or antigens on the cells, aiding laboratorians in the identification of cell lineage.  

Although widely used, to date, flow cytometry testing has not fulfilled its potential to provide laboratories with maximum return on the high capital cost associated with the purchase of a flow cytometer: methodology and data interpretation, clinical data sharing and education have all been hindered by the complexity and variability of test set-up and results analysis. For manually prepared and designed panels, each of the required number of antibodies must be titrated and validated, and then revalidated when combined with other antibodies – a process which itself may require further technical adjustment in order to achieve accurate results.

Quality assurance of the reagent cocktail demands rigorous documentation (dating, etc) at each step, including regular, ongoing testing to assess the quality of each batch. Lot variations, as well as stability issues, converge to add to the administrative burden. 

Manual antibody cocktail preparation is a process that is inherently fraught with the potential for errors. Dr Véronique Saada is a specialist practitioner in hematology at the leading cancer research centre, the Institut Gustave Roussy in Paris. She says: “There can be missing markers, and the wrong antibodies can be added,” raising the spectre of potential misinterpretation of the patient sample and an incorrect clinical conclusion that can have serious consequences for the patient.

In words that will resonate with lab technicians throughout the world, Dr Saada says: “Cocktail preparation is a complex, time consuming process involving individual pipetting of antibodies into the batch.” 

For the laboratory, the complexity of test preparation has important commercial ramifications. In some labs, technicians are employed solely to prepare flow cytometry analysis panels, says Mike Keeney, associate scientist at the Lawson Health Research Institute, London Health Sciences Centre, Ontario, Canada. And, with antibodies costing up to $1,000 each, errors and waste can be costly.


Technological development to detect cancers


Since June 2017, labs have benefited from US Food and Drug Administration authorized technology, designed to detect a range of leukemias and lymphomas, including chronic leukemia, acute leukemia, non-Hodgkin lymphoma, myeloma, myelodysplastic syndrome (MDS) and myeloproliferative neoplasms (MPN). Announcing the market approval of this first-in-type test, Alberto Gutierrez, director of the FDA’s office of in-vitro diagnostics and radiological health, said: “Laboratories and healthcare professionals now have access to an FDA-validated test that provides consistent results to aid in the diagnoses of these serious cancers. This represents a major step forward for the hematology-oncology community.”

The new technology, Beckman Coulter ClearLLab Reagents, have been authorized through the de novo premarket review pathway, a regulatory pathway for novel, low- to moderate-risk devices that are not substantially equivalent to an already marketed device. The authorization was supported by a study designed to demonstrate the test’s performance, which was conducted on 279 samples at four independent clinical sites. The study compared the test’s results to alternative detection methods used by the clinical sites. The study showed that the results of the test aligned with the study site’s final diagnosis 93.4% of the time and correctly detected that there was a cancer presence (i.e., cancer abnormality) 84.2% of the time.


Aligned with 2006 Bethesda International Consensus recommendations


A key factor in the success of the test on the global stage is its alignment with the world-famous 2006 Bethesda International Consensus recommendations on the immunophenotypic analysis of hematolymphoid neoplasia by flow cytometry. These recommendations set out the reagents and reporting for the flow cytometric diagnosis of hematopoietic neoplasia - and for hematology laboratories the world over represents a successful attempt to define a set of consensus reagents suitable for the initial evaluation of hematopoietic neoplasia.

The Bethesda committee included laboratory professionals from private, public, and university hospitals as well as large reference laboratories that routinely operate clinical flow cytometry laboratories with an emphasis on lymphoma and leukemia immunophenotyping. A survey of participants successfully identified the cell lineage(s) to be evaluated for each of a variety of specific medical indications and defined a set of consensus reagents suitable for the initial evaluation of each cell lineage.


Lower costs, less time and greater patient and professional satisfaction


For labs around the world, the availability of FDA and Bethesda International Consensus recommendations compliant panels, containing pre-mixed and optimised multi colour antibodies assay, has important implications. The Lawson Health Research Institute’s Mike Keeney estimates there can be 12-15% time and cost savings for an average hematological lab.

Savings from reduced manual input, reduced waste and errors, and inventory savings, can run into thousands of dollars. An additional benefit is improved work flow and a higher quality of the work experience for technicians. Senior research fellow, Dr Benjamin Hedley, also of the London Health Sciences Centre in Ontario, says: “We can move our highly qualified technicians away from essential but tedious manual tasks into more professionally satisfying data analysis.”

For patients, quicker and more accurate laboratory testing has obvious benefits for health. Less directly, the advent of standardized technology and procedure across the the global stage has important ramifications for the advancement of clinical education and research: research can now be shared across laboratories in confidence that results are not confounded by variables in the assembly and interpretation process, and that they conform with international guidelines. 

In short, says Mike Keeney, “this technology is a significant step forward on the path to standardization.”


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