2011-03-16

B-acute lymphoblastic leukemia (B-ALL)

Cellavision-assisted identification of subtle blasts in a blood smear from a patient with B-acute lymphoblastic leukemia (B-ALL)

B-acute lymphoblastic leukemia (B-ALL) can have morphology very similar to mature lymphocytes, but  modern hematology analyzers reliably will alert the operator with a “blast” flag (1, 2).  However, since these same analyzers have a significant false positive “blast” flagging rate (3, 4), most clinical laboratories will report possible leukemic blasts only after confirming their presence by manual microscopic review of stained blood smears.  Identification of ALL blasts in some smears requires experienced, expert interpretation, a resource not always readily available in many clinical laboratories.  CellaVision® DM96, an automated medical microscopy analyzer, allows remote access to images from blood smears, facilitating rapid, expert review of blood smears and identification of leukemic blasts. 

Remote review of images from a blood smear using CellaVision® DM96 allowed the accurate, rapid diagnosis of B-ALL in a 5 year old girl who presented to our hospital emergency room late on a Friday evening complaining of lethargy and abdominal pain for about one week.  The examining physician noted she was pale with petechiae on her lower legs.  Blood count plus differential revealed:

Blood Counts
Sysmex XE5000
Automated Differential
Sysmex XE5000
Manual Differential
Cellavision DM96 assisted
WBC: 4.5 x 103/ul
RBC: 1.72 x 106/ul
HGB: 4.7 gm/dL
MCV: 80.2 fL
RDW: 18%
PLT: 18 x 103/ul
Lymphocytes: 90.9%Neutrophils: 1.1%Monocytes: 6.9%Eosinophils: 0.2%
Basophils: 0.7%
Immature Gran: 0.2%
Lymphocytes:  52%Neutrophils: 2%Myelocytes: 1%
Blasts: 45%

The XE5000 hematology analyzer gave the following flags: Blasts? Immature Gran?

The smear review and CellaVision® DM96 images showed many blasts that were very small, hyperchromatic and easily confused with lymphocytes (Figure 1).  Through computer client-server access using CellaVision® DM96, the pathologist on call reviewed the smear images quickly, remotely and accurately.  From her office ten miles from the hospital, the pathologist confidently diagnosed probable leukemic blasts based on the smear images in CellaVision and then ordered flow cytometry on the blood which confirmed that the blood contained 40% B-ALL blasts with the typical immunophenotype (CD10+, CD19+, variable CD20+, dim CD22+, CD34+, CD38+, dim CD45+, cytoplasmic CD79a+, TdT+). 

Figure 1. Blood smear leukocyte images captured by Cellavision DM96.  The image in upper left shows the rare obvious leukemic blast next to a small, mature lymphocyte.  The image in upper right shows a small, mature lymphocyte.  The lower two images probably contain leukemic blasts, but their morphology is remarkably similar to lymphocytes.

This case illustrates the importance of flagging by hematology analyzers for alerting operators to the possible presence of leukemic blasts in blood.  Also, this case illustrates how CellaVision can facilitate rapid, remote pathologist review, expediting treatment for potentially life-threatening illness.

References

1. Fernandez-Castro M, Viloria A. Utility of the Technicon H-1 flags in the detection of peripheral blood blast cells of paediatric acute leukaemia patients. Acta Haematol 1995;93(1):9-12.

2. Hoyer JD, Fisher CP, Soppa VM, Lantis KL, Hanson CA. Detection and classification of acute leukemia by the Coulter STKS Hematology Analyzer. Am J Clin Pathol 1996;106(3):352-8.

3. Cornbleet PJ, Myrick D, Judkins S, Levy R. Evaluation of the CELL-DYN 3000 differential. Am J Clin Pathol 1992;98(6):603-14.

4. Kakkar N, Kaur R. Utility of white blood cell suspect flags and histogram pattern in the detection of acute leukemia by Advia-60 automated hematology analyzer. Indian J Pathol Microbiol 2004;47(3):322-6.

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