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U2AF1 Mutation Analysis Test

Last updated July 26, 2019

Approved by: Maulik P. Purohit MD, MPH

The U2AF1 Mutation Analysis Test helps detect alterations in the U2AF1 gene. It aids in the diagnosis of blood cell disorders, such as myelodysplastic syndromes.

What are other Names for this Test? (Equivalent Terms)

  • RNU2AF1 Mutation Analysis Test
  • U2 Small Nuclear Ribonucleoprotein Auxiliary Factor, 35-KD Subunit Mutation Analysis Test
  • U2(RNU2) Small Nuclear RNA Auxiliary Factor Binding Protein Mutation Analysis Test

What is U2AF1 Mutation Analysis Test? (Background Information)

  • U2AF1 mutation refers to an alteration in the U2AF1 gene. It is associated with blood disorders, including myelodysplastic syndromes and white blood cell cancer (leukemia)
  • The U2AF1 gene gives instructions for the U2AF1 protein. The U2AF1 protein is involved in a process called alternative splicing
  • Alternative splicing occurs in cells after genetic material has been converted to an intermediate compound, RNA, en route to being made into protein. Alternative splicing proceeds as follows:
    • RNA is fragmented, with some pieces subsequently being joined together (spliced) and others discarded
    • The discarded pieces are called introns, while the ones left in the final, mature RNA, are called exons
  • Alternative splicing is necessary for the proper conversion of genes into protein. It is especially important for cells undergoing growth and division, such as early blood cells. The U2AF1 protein is necessary for the normal processing of hundreds of genes
  • Alterations in the U2AF1 gene may result in a U2AF1 protein that is defective. The defective U2AF1 protein is unable to contribute normally to the alternative splicing process, which may cause a variety of problems converting genetic information into protein
  • The U2AF1 Mutation Analysis Test helps detect alterations in the U2AF1 gene. It aids in the diagnosis of blood cell disorders, such as myelodysplastic syndromes

The molecular testing, in general, can be performed using a variety of methods. Some of these methods include:

  • In situ hybridization technique, such as fluorescence in situ hybridization (FISH)
  • Immunohistochemistry (IHC)
  • Next-generation sequencing (NGS)
  • Polymerase chain reaction (PCR)
  • Comparative genomic hybridization (CGH)
  • Karyotyping including spectral karyotyping
  • mRNA analysis
  • Tissue microarrays (TMAs)
  • Southern blot test
  • Northern blot test
  • Western blot test
  • Eastern blot test

The methodology used for the test may vary from one laboratory to another. 

Note: Molecular testing has limitations due to the molecular method and genetic mutational abnormalities being tested. This can affect the results on a case-by-case basis. Consultation with your healthcare provider will help in determining the right test and right molecular method, based on individual circumstances.

What are the Clinical Indications for performing the U2AF1 Mutation Analysis Test?

Following are the clinical indications for performing the U2AF1 Mutation Analysis Test:

  • Fatigue
  • Shortness of breath
  • Unusual paleness (pallor) due to anemia
  • Easy or unusual bruising or bleeding
  • Pinpoint-sized red spots just beneath your skin caused by bleeding (petechiae)
  • Frequent infections

In general, the molecular genetic testing is undertaken in the following situations:

  • To assist (and in some cases, confirm) the initial diagnosis
  • To distinguish other tumors/conditions that have similar histological features, when examined by a pathologist under the microscope
  • To help in determining treatment options
  • To confirm recurrence of the tumor: Tumor recurrence can either be at the original tumor site, or at a distant location (away from the initial site)

How is the Specimen Collected for U2AF1 Mutation Analysis Test?

Following is the specimen collection process for U2AF1 Mutation Analysis Test:

The specimen sample requirements may vary from lab to lab. Hence, it is important to contact the testing lab for exact specimen requirements, before initiating the testing process.

  • Sample on which the test is performed may include:
    • Fresh tumor tissue during biopsy
    • Formalin-fixed paraffin-embedded solid tumor tissue (FFPE tumor tissue), often referred to as paraffin block of the tumor
    • Unstained tissue slides
  • Process of obtaining the sample: As outlined by the laboratory testing facility
  • Preparation required: As outlined by the laboratory testing facility


  • In some cases, a different source of specimen (such as peripheral blood, bone marrow biopsy specimen, or other body fluids) may be acceptable to the laboratory performing the test
  • Occasionally, additional samples may be required to either repeat the test or to perform follow-up testing
  • Depending on the location of testing, it may take up to 2 weeks’ turnaround time, to obtain the test results
  • Many hospitals preserve the paraffin blocks for at least 7 years. In general, older paraffin blocks (over 5 years) may affect the detection of specific mutations, due to degradation of the tumor specimen over time

Cost of U2AF1 Mutation Analysis Test:

  • The cost of the test procedure depends on a variety of factors, such as the type of your health insurance, annual deductibles, co-pay requirements, out-of-network and in-network of your healthcare providers and healthcare facilities
  • In many cases, an estimate may be provided before the test is conducted. The final amount may depend upon the findings during the test procedure and post-operative care that is necessary (if any)

What is the Significance of the U2AF1 Mutation Analysis Test Result?

  • The presence of a mutation in the U2AF1 gene indicates a positive result for the U2AF1 Mutation Analysis Blood Test. This may point to a diagnosis of myelodysplastic syndrome

The laboratory test results are NOT to be interpreted as results of a "stand-alone" test. The test results have to be interpreted after correlating with suitable clinical findings and additional supplemental tests/information. Your healthcare providers will explain the meaning of your tests results, based on the overall clinical scenario.

Additional and Relevant Useful Information:

  • The U2AF1 gene resides on a position of the chromosome called 21q22.3 i.e., the long (q) arm of chromosome 21 in location 22.3.
  • Many laboratories may not have the capability to perform this test. Only highly-specialized labs with advanced facilities and testing procedures may perform this test

Certain medications that you may be currently taking may influence the outcome of the test. Hence, it is important to inform your healthcare provider, the complete list of medications (including any herbal supplements) you are currently taking. This will help the healthcare provider interpret your test results more accurately and avoid unnecessary chances of a misdiagnosis.

Please visit our Laboratory Procedures Center for more physician-approved health information:


References and Information Sources used for the Article:

Helpful Peer-Reviewed Medical Articles:

Reviewed and Approved by a member of the DoveMed Editorial Board
First uploaded: May 29, 2017
Last updated: July 26, 2019