By Nicholas Borgert

As a diagnostic for detecting, analyzing, and monitoring a variety of cancers in adults and children, flow cytometry has gained universal acceptance. But the implementation and ongoing costs of this advanced technology are a major barrier for lab facilities and hospitals faced with limited capital and modest testing volumes. Adding to that concern, Medicare reimbursement for flow cytometry and other services has been cut drastically.  

Bruce Davis, MD

In response, US LABS, an Irvine, Calif-based anatomic pathology reference laboratory specializing in high-quality, rapid-response cancer testing, has developed Virtual Flow™, an innovative flow cytometry online reporting system. The Virtual Flow service offers labs of any size and location access to the US LABS staff of Board-certified hematopathologists and their expertise in flow cytometry.

At the core of flow cytometry is the ability to correctly identify and classify the types of cells involved in such malignant processes as leukemia and lymphoma. The US LABS flow cytometry department is capable of running more than 40 different antibodies in many combinations and delivering accurate statistical percentages for each antibody. The company’s basic panel uses 31 different antibodies in various combinations and 50,000 to 600,000 individual cells to quickly and accurately quantify the percentage of positivity for each cell type.

Using a large number of antibodies in various combinations provides for very specific identifications of cells, lineages, maturational stages, and abnormal populations. These statistics can be used to monitor the course of the disease process and treatment. The presence of abnormal cells can be detected in less than 1% of the total cells. This enables early detection and monitoring of relapse or residual disease. In most cases, turnaround time for cytometry profiling is less than 24 hours.

Virtual Flow focuses on cancers of the blood, including leukemia and lymphoma. Like immunohistochemistry, flow cytometry uses antibodies to measure characteristics of a cancerous cell, including those related to the aggressiveness of a particular cancer.

Fully licensed, highly skilled technologists perform US LABS’ flow cytometry studies. They subject the findings to rigorous quality controls. All results are double-checked for accuracy; first by a knowledgeable flow cytometry supervisor or laboratory scientist and then by a qualified pathologist.

Faster turnaround and the diagnostic information provided by flow cytometry translates to better and earlier treatment for patients. Histograms can be viewed or printed out anywhere and reports can be created, edited or customized.

Bruce Davis, MD, plays a pivotal role in the Virtual Flow on-line technology service. In his position as US LABS director of hematopathology, Davis directs the cancer lab’s clinical efforts in flow cytometry. He reads cases, consults with pathologists from around the country on patient conditions and treatment options, and guides efforts focused on development of newer, faster, and better diagnostic tests. He is a world-respected flow cytometry expert and an authority in the analysis of red cells and clinical applications for red cell flow cytometry.

Involved with flow cytometry and related technologies for the past 25 years, Davis was recognized with the 2004 Wallace Coulter Award from the Clinical Cytometry Society in recognition of his contributions to the field. An author and frequent speaker on flow cytometry and its applications, he co-founded the International Society of Laboratory Hematology and the Journal of Laboratory Hematology.

Davis holds three patents. He was a principal organizer and author of the North American and International clinical flow cytometry consensus papers. He now chairs the Hematology Area Committee of the Clinical and Laboratory Standards Institute (formerly NCCLS). His past associations have included diagnostics and research posts with hospitals and health systems in Michigan, Texas, New Hampshire, and Maine.

Davis recently responded to questions from Clinical Lab Products about Virtual Flow, its applications and advantages, and its future.

CLP: What are the benefits of Virtual Flow cytometry?
Davis: US LABS’ Virtual Flow service allows local pathologists to have access to the newer technologies and be able to offer their patients the same level of service previously available only at academic medical centers and reference laboratories. But tapping into the diagnostics advantages offered by the latest hardware, software, and data storage support isn’t the only reason a diagnostic facility would turn to US LABS’ virtual cytometry.

The Virtual Flow program provides the client access and the best opinions of experienced hematopathologists for same-day consultation on the more challenging diagnostic cases. By reducing the time to a definitive diagnosis, such immediate consultations enable the local pathologist to provide patients with faster and more cost-efficient diagnostic services within his or her community.

CLP: What is a typical cost of a flow cytometry system in today’s market?
Davis: Costs can vary, but a rough estimate is $150,000 for a single flow cytometer, another $50,000 in ancillary lab equipment that may be required (including safety hoods, centrifuges, computers, and cell washers) and initial reagents for start-up on the order of $5,000 to $10,000. The staffing needs are usually a minimum of 1.5 FTE (full-time employee) senior medical technologist ($75,000 per year salary plus benefits). The break-even cost from a financial perspective would be covered by approximately 500 cases for leukemia/lymphoma evaluation per year, but this does not take into account that a volume of probably 4 to 5 times that is the minimum to keep up technical and interpretive competence.

CLP: Beyond the cost factor, how does US LABS’ Virtual Flow cytometry improve care for patients?
Davis: Test results are generally available on the same lag time as seen with an in-house flow cytometry lab and typically one day sooner than the average reference laboratory. The results are as comprehensive as any reference or academic medical center laboratory. The ideal client is a pathologist who is trained as a hematopathologist and has experience in the interpretation of flow cytometry results. US LABS provides a 2-day training course to familiarize the client with the virtual reporting software, antibody combinations and diagnostic patterns used by US LABS. It also covers how to optimize the full spectrum of services offered by US LABS and our partner laboratories.

CLP: What makes the US LABS cytometry service a better value, a better choice compared to other virtual services on the market?
Davis: US LABS is the leader in this service offering, and introduced the Virtual Flow cytometry service to the marketplace in December 2002. Although the imitation by other reference laboratories is flattering, we continue to improve the offering through IT advances. At present, the US LABS product continues to be more sophisticated, and it offers true ease of use.

CLP: US LABS offers an expanding Virtual portfolio, including Virtual Image and Virtual IHC. Is expertise in generating and sharing information becoming as vital to improving patient care as science and medical advances?
Davis: Ease of use provides greater availability and more effective use of scientific and technologic advances. However, it is the improved diagnostics that continues to be a focus at US LABS, which in turn is supported by our Virtual product portfolio and IT implementation.

We believe that in order for the diagnostic advances to have a significant impact on patient care, it needs to be provided at the local level. It is more cost-efficient to bring these diagnostic services to the community health care facility than it is to move individual patients to a select number of sophisticated medical centers.

CLP: Dr. Davis, look into the future and talk about the next best advances you see on the horizon in the flow cytometry area?
Davis: To date, the technology of flow cytometry in laboratory medicine has provided diagnostic assays for relatively infrequent diseases, such as leukemia and lymphoma. I am aware of new assays being developed to improve the detection of infection and sepsis using flow cytometry to detect the expression of CD64 on neutrophils -- something that will have practical utility to millions of patients annually.

I also expect the combination of cellular measurements and bead-based assays on a flow-cytometric platform to provide a multiplexed assay to address disease diagnosis and prognosis. Once the molecular array studies have defined the most useful biomarkers for disease diagnosis and prognosis, it is likely that a flow-cytometric platform will prove to be the ideal solution to the need for both sensitivity and cost-effectiveness.

Nicholas Borgert is a contributing writer for Clinical Lab Products.