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Interpretive Handbook

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Test 89292 :
Nucleophosmin (NPM1) Mutation Analysis

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Acute myelogenous leukemia (AML) is a heterogenous group of neoplasms. While cytogenetic aberrations detected at the time of diagnosis are the most commonly used prognostic feature, approximately 20% of AML cases show a normal karyotype, which is considered an intermediate-risk feature. Within this group, FLT3 mutations are considered indicators of poor prognosis. However, in the absence of a FLT3 mutation, the presence of a nucleophosmin (NPM1) mutation is associated with good prognosis. Thus, in patients with newly diagnosed AML, those with normal karyotype, no FLT3 mutation, and a NPM1 mutation are considered to have a better prognosis than patients in the same group with neoplasms lacking a NPM1 mutation.

Useful For Suggests clinical disorders or settings where the test may be helpful

As a prognostic indicator in patients with newly diagnosed acute myelogenous leukemia with normal karyotype and no FLT3 mutation

Interpretation Provides information to assist in interpretation of the test results

The assay will be interpreted as positive or negative for the NPM1 mutation. In patients with newly diagnosed acute myelogenous leukemia, a normal karyotype, and no FLT3 mutation, the presence of NPM1 mutation is an indicator of good prognosis.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

The test is designed to be used at the time of diagnosis when the mutation burden is high. The sensitivity is not adequate for monitoring patients during therapy as a test of minimal residual disease.

 

At this time, there is no clinical indication for assessing NPM1 mutation status at any time other than initial diagnosis.

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

An interpretive report will be provided.

Clinical References Provides recommendations for further in-depth reading of a clinical nature

1. Thiede C, Koch S, Creutzig E, et al: Prevalence and prognostic impact of NPM1 mutations in 1485 adult patients with acute myeloid leukemia (AML). Blood 2006;107:4011-4020

2. Falini B, Mecucci C, Tiacci E, et al: Cytoplasmic nucleophosmin in acute myelogenous leukemia with a normal karyotype. N Engl J Med 2005;352(3):254-266


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