Test Overview
Test Methodology

Multiplex Polymerase Chain Reaction (PCR) with Capillary Electrophoresis

Test Usage

Mutations within exon 12 of the JAK2 gene occur in most cases of JAK2 V617F-mutation negative polycythemia vera. Testing for JAK2 exon 12 mutations may aid in the diagnosis of polycythemia vera, and is recommended in patients with JAK2 V617F-negative erythrocytosis. This test will qualitatively detect JAK2 exon 12 mutations in peripheral blood or bone marrow specimens with a sensitivity down to 2% mutant allele. This is a second order test and should be used only following a JAK2 V617F-negative result.

Reference Range *

Interpretive report provided.

* Reference ranges may change over time. Please refer to the original patient report when evaluating results.

Test Limitations

The limit of detection of this assay is 4% mutation-bearing cells. Mutations may not be detected in samples with a neoplastic burden below this level. In addition, this test will only detect insertions, deletions or K539L. Rare substitution mutations other than K539L (accounting for less than 5% of described JAK2 exon 12 mutations) will not be detected.

Test Details
Days Set Up
Monday - Thursday
Analytic Time

2 - 7 days

Soft Order Code
MiChart Code
JAK2 Exon 12 Mutation
  • EXON12
  • JAK2 Exon 12 Mutation Detectio
  • EX12
  • Polycythemia Vera
Molecular Diagnostics
Molecular Diagnostics
Specimen Requirements
Collection Instructions

Collect blood or bone marrow in a lavender top tube. Refrigerate and send intact blood or bone marrow specimen within 48 hours of collection. Fresh cell suspensions in RPMI should be refrigerated and sent, preferably within 48 hours. Frozen cell suspensions – preferably frozen with 1 hour of collection – may also be sent frozen on dry ice.

Alternate Specimen
The preferred specimen is whole blood or bone marrow collected in EDTA (lavender top). However, ACD (yellow top) and heparin (green top) may also be accepted. Previously extracted DNA may also be accepted.
This test is not indicated for inpatient evaluation of acute thrombosis.
Normal Volume
5 mL EDTA (lavender) whole blood; 3 mL EDTA (lavender) bone marrow; Fresh/frozen cells in RPMI. Extracted DNA is also acceptable if extracted in a CLIA certified laboratory.
Additional Information

By ordering this test the clinician acknowledges that informed consent has been obtained from the patient as required by applicable state or federal laws and the ordering clinician has authorization from the patient permitting MLabs to report the test results to the ordering clinician. Test includes pathologist interpretation of results billed as a separate additional charge. This test is not available without interpretation.

CPT Code
Fee Code
Pro Fee CPT
NY State Approved