Vol. 24 • Issue 5 • Page 18
In some hematology laboratories, such as H. Lee Moffitt Cancer Center & Research Institute in Tampa, Florida, a normal sample is a rare event. The Institute’s hematology department is reporting manual differentials or a smear review on 300-350 smears per day using a cell image analyzer. Manual (not microscopic) differentials using the cell image analyzer are performed on approximately 20% of CBCs that have automated diffs ordered. Additionally, another 30% of samples may require some sort of manual review. For example, suspected blasts will trigger a manual review on the image analyzer, while a high percentage of monocytes (20% or 1.0 absolute) will trigger a slide review.
In addition to having 206 beds, they also receive more than 500 outpatient samples per day, many of whom have hematologic malignancies or solid tumors. In this environment a cell image analyzer has become a critical component of laboratory testing; it allows fewer technologists to handle the differential workload, improves the turnaround time, helps to standardize cell identification, and assists in offsetting staffing shortages.
The Ultimate in Connectivity
Moffitt has 10 hematopathologists who work with the 15 hematologists and 15 mid-level practitioners in the malignant hematology clinic. Their access to the cell images on the analyzer is supported by a system that can manage up to 50 simultaneous remote logins. Clinicians are able to view a patient’s slide remotely in the clinic even if the differential has not been completed and released in the hematology laboratory.
In many laboratories, neutropenic samples require time-consuming microscopic differentials. But this is not the case at Moffitt where neutropenic samples are reported without review because of the accuracy of the automated differentials from the CBC analyzer units.
Jeanine Jaehne, MHA, MT(ASCP), conducted a validation study of the department’s new hematology analyzers to evaluate the accuracy of automated WBC differentials versus microscopic differentials in neutropenic samples. The study showed that even if the sample contained flags, the new analyzers provided a WBC differential that was not only better than their old equipment, it was even more accurate than a manual review. These samples are now autoverified and the laboratory has an autovalidation rate of 77 percent despite the number of abnormal and neutropenic samples.
When the pathology department discussed this new reporting policy with medical staff, the clinicians agreed that it was not ðunexpected when blasts or immature cells were present. Furthermore, the clinicians would rather evaluate the patient using the absolute neutrophil count in conjunction with clinical evaluation. If they felt that they also needed a manual differential, the hematology department would perform one on a buffy coat. There are a few exceptions that still require hand smears and microscopic review – one of which is an albumin slide.
Sharing Images for Patient Care, Education
Moffitt’s cell image analyzer comes with an onboard reference library; however, even with their high acuity patient population, the hematology department has been able to construct its own customized library for white cells and red cells. Jaehne describes how she has created a dedicated atlas specific for the Moffitt patient population. For example, if she observes a cell of interest, she can capture the image and save it to her directory for others to reference.
Additionally, Jaehne says that Moffitt specifically differentiates ovalocytes versus eliptocytes and identifies red cell fragments in addition to shistocytes, since they tend to see an increased level of RBC fragments due to the treatment patients receive. These procedures are made simpler for the lab staff with the automated cell image analyzer.
As a result of the analyzer’s capability to help technologists identify difficult cells, Moffitt’s hematology department has been able to standardize WBC differential reporting on atypical or abnormal cells.
Jaehne also uses unusual cells to teach technologists how to help identify cells by observing “the company that they keep,” meaning that you can’t look at just one cell in isolation. Cells need to be evaluated in the context of the other cells in the sample, and the analyzer allows you to view them side-by-side to determine similarities of one cell with others, or even with groups of cells. For example, the lab technologist can bring up lymphocytes and blasts next to one another to see which group the cell in question most resembles.
“Being able to view categories of cells gives you better options,” she explains. “Not every single monocyte, for example, looks like every other monocyte. You are looking at a snapshot of the cell at a point in time when the slide was made at a stage in the maturation of the cell. Being able to evaluate similarities has been a wonderful feature of differential standardization.”
Particularly challenging morphology cases are those patients who have either failed therapy or those who must come to Moffitt for a therapy not available elsewhere. “These cells do not appear as a ‘typical form’ of the leukemia they have,” said Jaehne. “Treated cells are often simply ‘ugly,’ and it’s difficult to know if it is a tumor cell. If these cells are in the peripheral blood, it is not usually a good sign.”
Jaehne agrees that she and her hematology colleagues are lucky to see the blood dyscrasias they do. Many medical technologists may not see these presentations in the whole of their career. “I’m sad to say that what is ordinary for us becomes extraordinary for others,” said Jaehne.
Another benefit of having the cell image analyzer is the access it provides the physician to a patient’s smear. This allows the physician to view the cells that were classified and any cells that were suspect. Pathologists and hematology fellows who are studying for their chosen career are able to see exactly how cells were classified. They don’t need to hunt around to find that one cell someone else asked them to review. There is a great deal of interaction between the hematology laboratory staff and the pathologists and fellows. The technologists can pull up exact cells of concern for the physicians to see.
Consistency is Critical
An age-old complaint about manual white cell differentials has been the variability in cell classification within in a single laboratory. Cell image analyzers provide the mechanism for substantially reducing this variability while providing a teaching platform for advancing identification skills of early and atypical cell forms.
At Moffitt, patients do not come in for occasional blood work. Rather, they have acute conditions that bring them back three times in the same week or even possibly each day for a course of treatment. Jaehne stresses the importance of consistently identifying cells. Simply identifying a single blast may be the harbinger of a relapse or the need for a bone marrow biopsy. The use of cell imaging analysis has provided the opportunity to maintain the level of consistency that benefits patient care.
Carl Trippiedi is senior product manager, Sysmex America, Inc.