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Order Code JAK2B JAK2 V617F Mutation Detection, Blood

Reporting Name

JAK2 V617F Mutation Detection, B

Useful For

Aiding in the distinction between a reactive blood cytosis and a chronic myeloproliferative disorder using peripheral blood specimens

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Whole Blood EDTA


Shipping Instructions


Specimen must arrive within 7 days of collection.



Specimen Required


Container/Tube:

Preferred: Lavender top (EDTA)

Acceptable: Yellow top (ACD)

Specimen Volume: 4 mL

Collection Instructions:

1. Invert several times to mix blood.

2. Send whole blood specimen in original tube. Do not aliquot.


Specimen Minimum Volume

1 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Whole Blood EDTA Ambient (preferred) 7 days PURPLE OR PINK TOP/EDTA
  Refrigerated  7 days PURPLE OR PINK TOP/EDTA

Reference Values

An interpretive report will be provided.

Day(s) Performed

Monday through Saturday

CPT Code Information

81270-JAK2 (Janus kinase 2) (eg, myeloproliferative disorder) gene analysis, p.Val617Phe (V617F) variant

Method Description

Genomic DNA is extracted, and 2 polymerase chain reaction (PCR) amplifications are used for each sample. In each reaction, a short fragment of genomic DNA, including the variant site, is amplified using quantitative PCR in a real-time PCR instrument. In the first reaction, the 5' terminal base of the reverse primer matches the mutated sequence, and the PCR conditions are such that it will only bind mutated DNA. In the second reaction, the 5' terminal base of the reverse primer matches the wild-type sequence, and the PCR conditions are such that it will only bind the wild-type sequence. In both reactions, the PCR is monitored using TaqMan probe chemistry. The amount of mutated DNA and the amount of wild-type DNA is measured for each sample. In each run, the amount of mutated and wild-type DNA in a calibrator DNA sample is also measured. The calibrator is a mixture of DNA from a positive cell line (HEL) and a negative cell line (HL60) that is frozen in aliquots and expected to give an identical result in each run. Deviations in the calibrator result are assumed to be due to deviations in the run conditions and the sample results are corrected accordingly. Following each reaction, Relative Quantification Software is used to calculate the normalized mutated:wild-type ratio, which is expressed as a unitless ratio following correction with the calibrator data.

 

The formula for the normalized ratio is as follows:

 

Normalized ratio =

mutated/wild type (sample)

mutated/wild type (calibrator)

 

The final result is reported as percent JAK2 V617F of total JAK2 (ie, [mutated/mutated + wild type] x 100%) calculated from the normalized mutated:wild-type ratio.(Unpublished Mayo method)

Reject Due To

Gross hemolysis Reject
Moderately to severely clotted Reject

Method Name

Quantitative Polymerase Chain Reaction (PCR)

Forms

1. Hematopathology Patient Information (T676)

2. If not ordering electronically, complete, print, and send a Hematopathology/Cytogenetics Test Request (T726) with the specimen.