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HelpTEST ID MPNCM Myeloproliferative Neoplasm, CALR with Reflex to MPL, Varies
Reporting Name
MPN (CALR, MPL) ReflexSpecimen Type
VariesShipping Instructions
Specimen must arrive within 7 days of collection.
Necessary Information
The following information is required:
1. Pertinent clinical history
2. Clinical or morphologic suspicion
3. Date of collection
4. Specimen source
Specimen Required
Submit only 1 of the following specimens:
Specimen Type: Whole Blood
Container/Tube: Lavender top (EDTA) or yellow top (ACD-B)
Specimen Volume: 3 mL
Collection Instructions:
1. Invert several times to mix blood.
2. Send whole blood specimen in original tube. Do not aliquot.
3. Label specimen as whole blood.
Specimen Stability Information: Ambient (preferred)/Refrigerate
Specimen Type: Bone marrow
Container/Tube: Lavender top (EDTA) or yellow top (ACD-B)
Specimen Volume: 2 mL
Collection Instructions:
1. Invert several times to mix bone marrow.
2. Send bone marrow specimen in original tube. Do not aliquot.
3. Label specimen as bone marrow.
Specimen Stability Information: Ambient (preferred)/Refrigerate
Specimen Type: Extracted DNA from blood or bone marrow
Container/Tube: 1.5 to 2 mL tube
Specimen Volume: Entire specimen
Collection Instructions:
1. DNA must be extracted from blood or bone marrow within 7 days of collection.
2. Label specimen as extracted DNA and source of specimen.
3. Provide volume and concentration of the DNA.
Specimen Stability Information: Frozen (preferred) 1 year/Refrigerate/Ambient
Additional Information: DNA must be extracted in a CLIA-certified laboratory or equivalent and must be extracted from a specimen type listed as acceptable for this test (including applicable anticoagulants). We cannot guarantee that all extraction methods are compatible with this test. If testing fails, one repeat will be attempted, and if unsuccessful, the test will be reported as failed and a charge will be applied.
Specimen Minimum Volume
Whole blood, bone marrow: 0.5 mL; Extracted DNA: 50 mcL at 20 ng/mcL concentration
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Varies | Varies | 7 days |
Special Instructions
Testing Algorithm
This test reflexively evaluates for variants in the CALR and MPL genes commonly associated with BCR::ABL1-negative myeloproliferative neoplasms. The testing sequence is based on the reported frequency of gene variants in this disease group. It is usually ordered when a JAK2 V617F result is known to be negative. Initial testing evaluates for the presence of the CALR insertions and deletions. If out-of-frame CALR insertions or deletions are detected, the testing algorithm ends. If the CALR result is negative or an in-frame CALR insertion or deletion is identified, then testing proceeds, at an additional charge, to evaluate for variants in exon 10 of the MPL gene by Sanger sequencing. An integrated report is issued with the summary of test results.
For more information see:
-Myeloproliferative Neoplasm: A Diagnostic Approach to Bone Marrow Evaluation
-Myeloproliferative Neoplasm: A Diagnostic Approach to Peripheral Blood Evaluation
Method Name
Polymerase Chain Reaction (PCR) and Fragment Analysis
Reject Due To
| Gross hemolysis | Reject |
| Paraffin-embedded bone marrow aspirate clot or biopsy blocks | Reject |
| Slides | Reject |
| Paraffin shavings | Reject |
| Moderately to severely clotted | Reject |
Reference Values
An interpretive report will be provided.
Day(s) Performed
Monday through Friday
Reflex Tests
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| MPNML | MPL Exon 10 Sequencing, Reflex | No, (Bill Only) | No |
Report Available
7 to 10 daysSpecimen Retention Time
Whole blood, bone marrow: 2 weeks; Extracted DNA: 3 monthsPerforming Laboratory
Mayo Clinic Laboratories in Rochester
CPT Code Information
81219-CALR (calreticulin) (eg, myeloproliferative disorders), gene analysis, common variants in exon 9
81339 -MPL (MPL proto-oncogene, thrombopoietin receptor) (eg, myeloproliferative disorder) gene analysis; sequence analysis, exon 10 (if appropriate)
Forms
If not ordering electronically, complete, print, and send a Hematopathology/Cytogenetics Test Request (T726) with the specimen.
Useful For
Aiding in the distinction between a reactive cytosis and a myeloproliferative neoplasm when JAK2V617F testing result is negative
Clinical Information
The JAK2 V617F variant is present in 95% to 98% of patients with polycythemia vera, 50% to 60% of patients with primary myelofibrosis (PMF), and 50% to 60% of patients with essential thrombocythemia (ET) patients. Detection of the JAK2 V617F variant helps establish the diagnosis of a myeloproliferative neoplasm (MPN). However, a negative JAK2 V617F result does not indicate the absence of MPN. Other important molecular markers in BCR::ABL1-negative MPN include CALR exon 9 variants (20%-30% of PMF and ET) and MPL exon 10 variants (5%-10% of PMF and 3%-5% of ET). Variants in JAK2, CALR, and MPL are essentially mutually exclusive. A CALR variant is associated with decreased risk of thrombosis in both ET and PMF and confers a favorable clinical outcome in patients with PMF. A triple negative (JAK2 V617F, CALR, and MPL-negative) genotype is considered a high-risk molecular signature in PMF.