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HelpTest Code LAB2033 JAK2 V617F Mutation Detection, Blood
Additional Codes
JAK2B
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 EDTAShipping 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 |
On-campus collections: Tube to 99 or deliver to University Extension Hospital Room EH318
Send in original tube, Ambient temp.
Off-campus collections: Send in original tube. Do NOT Spin! Do NOT Share! Specimen to be stored/transported at Ambient temp.
Special Instructions
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
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| JAK2B | JAK2 V617F Mutation Detection, B | 43399-5 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 39722 | JAK2 Result | 53761-3 |
| 29590 | JAK2 V617F Mutation Detection, B | 43399-5 |
Testing Algorithm
For more information see:
-Erythrocytosis Evaluation Testing Algorithm
-Myeloproliferative Neoplasm: A Diagnostic Approach to Peripheral Blood Evaluation
Interpretation
The results will be reported as 1 of the 2 states:
-Negative for JAK2 V617F variant
-Positive for JAK2 V617F variant
Positive variant status is highly suggestive of a myeloid neoplasm but must be correlated with clinical and other laboratory features for definitive diagnosis.
Negative variant status does not exclude the presence of a myeloproliferative neoplasm or other neoplasm.
Results below the laboratory cutoff for positivity are of unclear clinical significance at this time.
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)
Report Available
2 to 5 daysSpecimen Retention Time
Whole blood: 2 weeks; Extracted DNA: 3 monthsReject 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.