Acute myeloid leukemia laboratory tests
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Raviteja Guddeti, M.B.B.S. [2]
Overview
Laboratory Findings
- Complete blood count and differential count - an abnormal result is typically the first clue to a diagnosis of AML. Findings include:
- Leukocytosis
- Leukemic blasts
- Thrombocytopenia
- Anemia - decreased red cell count
- Leucopenia (sometimes)
- Bone marrow examination - is often performed to identify the type of abnormal blood cells; however, if there are many leukemic cells circulating in the peripheral blood, a bone marrow biopsy may not be necessary.
Marrow or blood is examined via light microscopy as well as flow cytometry to diagnose the presence of leukemia, to differentiate AML from other types of leukemia (e.g. acute lymphoblastic leukemia), and to classify the subtype of disease.
- A sample of marrow or blood is typically also tested for chromosomal translocations by routine cytogenetics or fluorescent in situ hybridization.
The diagnosis and classification of AML can be challenging, and should be performed by a qualified hematopathologist or hematologist. In straightforward cases, the presence of certain morphologic features (such as Auer rods) or specific flow cytometry results can distinguish AML from other leukemias; however, in the absence of such features, diagnosis may be more difficult.[1]
![AML - Auer Rods, DIC[2]](/index.php/File:AML.jpg)
![AML (with Auer Rods)[3]](/index.php/File:AML_(with_Auer_Rods).jpg)
According to the widely used WHO criteria, the diagnosis of AML is established by demonstrating involvement of more than 20% of the blood and/or bone marrow by leukemic myeloblasts.[4] AML must be carefully differentiated from "pre-leukemic" conditions such as myelodysplastic or myeloproliferative syndromes, which are treated differently.
Because acute promyelocytic leukemia (APL) has the highest curability and requires a unique form of treatment, it is important to quickly establish or exclude the diagnosis of this subtype of leukemia. Fluorescent in situ hybridization performed on blood or bone marrow is often used for this purpose, as it readily identifies the chromosomal translocation (t[15;17]) that characterizes APL.[5]
References
- ↑ Abeloff, Martin et al. (2004), p. 2835.
- ↑ http://picasaweb.google.com/mcmumbi/USMLEIIImages
- ↑ http://picasaweb.google.com/mcmumbi/USMLEIIImages
- ↑ Harris N, Jaffe E, Diebold J, Flandrin G, Muller-Hermelink H, Vardiman J, Lister T, Bloomfield C (1999). "The World Health Organization classification of neoplastic diseases of the hematopoietic and lymphoid tissues. Report of the Clinical Advisory Committee meeting, Airlie House, Virginia, November, 1997". Ann Oncol. 10 (12): 1419–32. PMID 10643532.
- ↑ Grimwade D, Howe K, Langabeer S, Davies L, Oliver F, Walker H, Swirsky D, Wheatley K, Goldstone A, Burnett A, Solomon E (1996). "Establishing the presence of the t(15;17) in suspected acute promyelocytic leukaemia: cytogenetic, molecular and PML immunofluorescence assessment of patients entered into the M.R.C. ATRA trial. M.R.C. Adult Leukaemia Working Party". Br J Haematol. 94 (3): 557–73. PMID 8790159.