Test Details
Methodology
Amplicon-based Next Generation Sequencing
Result Turnaround Time
7 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Use
Molecular testing of blood or bone marrow is useful in the evaluation of suspected myeloproliferative neoplasms (MPN). Mutations in the JAK2, MPL and CALR genes are present in virtually all MPNs and their presence help distinguish benign reactive processes from clonal neoplasms. These mutations are generally considered mutually exclusive, although concurrent clones have been reported in rare patients.
The JAK2 (Janus kinase 2) gene encodes for a non-receptor protein tyrosine kinase that activates cytokine and growth factor signaling. The V617F (c.1849 G>T) mutation results in constitutive activation of JAK2 and downstream STAT5 and ERK signaling. The V617F mutation is observed in approximately 95% of polycythemia vera (PV), 60% of essential thrombocythemia (ET) and primary myelofibrosis (PMF). It is also infrequently present (3-5%) in myelodysplastic syndrome, chronic myelomonocytic leukemia and other atypical chronic myeloid disorders. JAK2 mutation allele burden correlates with clinical phenotype, with low levels of mutant allele characterized by thrombocytosis, intermediate levels with erythrocytosis and high mutant allele burden, correlating with enhanced myelopoiesis of the BM, leukocytosis, increasing spleen size and circulating CD34-positive cells.
The CALR (Calreticulin) gene encodes for a multifunctional calcium-binding protein involved in many cellular activities such as growth, proliferation, adhesion and programmed cell death. Among patients with JAK2-negative MPNs, CALR mutations are found in approximately 70% of patients with JAK2-negative essential thrombocythemia (ET) and 60-88% of patients with JAK2-negative primary myelofibrosis(PMF). Only a minority of patients (approximately 8%) with myelodysplasia have mutations in the CALR gene. CALR mutations are rarely detected in patients with de novo acute myeloid leukemia, chronic myelogenous leukemia, lymphoid leukemia or solid tumors. CALR mutations are not detected in polycythemia and generally appear to be mutually exclusive with JAK2 mutations and MPL mutations. The majority of mutational changes involve a variety of insertion or deletion mutations in exon 9 of the calreticulin gene: approximately 53% of all CALR mutations are a 52 bp deletion (type-1) while the second most prevalent mutation (approximately 32%) contains a 5 bp insertion (type-2). Other mutations (non-type 1 or type 2) are seen in a small minority of cases. CALR mutations in PMF tend to be associated with a favorable prognosis compared to JAK2V617F mutations, whereas primary myelofibrosis negative for CALR, JAK2V617F and MPL mutations (so-called triple negative) is associated with a poor prognosis and shorter survival.
The MPL (myeloproliferative leukemia virus oncogene) gene encodes the thrombopoietin receptor, which regulates hematopoiesis and megakaryopoiesis. Activating MPL mutations are associated with a subset of myeloproliferative neoplasms and acute megakaryoblastic leukemia. MPL W515 mutations are present in approximately 5-8% of patients with primary myelofibrosis (PMF) and 1-4% of patients with essential thrombocythemia (ET). The S505 mutation is detected in patients with hereditary thrombocythemia.
Limitations
This assay has a sensitivity of approximately 1% VAF for JAK2V617F mutations and 2.5% VAF for CALR and MPL mutations. Deletions in CALR up to 70 bp and insertions up to 12 bp have been detected in validation studies.
This test was developed and its performance characteristics determined by Labcorp. It has not been cleared or approved by the Food and Drug Administration.
References
Specimen Requirements
Specimen
Whole blood or bone marrow
Volume
3 to 5 mL whole blood or 1 to 2 mL bone marrow
Minimum Volume
3 mL whole blood or 1 mL bone marrow
Container
Lavender-top (EDTA) tube, green-top (sodium heparin) tube, yellow-top (ACD) tube, tan-top (K2-EDTA) tube or pink-top (K2-EDTA) tube
Collection Instructions
Submit at room temperature. Specimens should arrive in the laboratory within 48 hours of collection. Indicate date and time of collection on test request form.
Storage Instructions
Ship at room temperature. If specimen is to be stored prior to shipment, store at 2°C to 8°C.
Causes for Rejection
Specimen does not meet all of the criteria for sample type, container, minimum volume, collection and storage; frozen whole blood or marrow; leaking tube; clotted blood or marrow; grossly hemolyzed or otherwise visibly degraded; contamination by another specimen; specimen containing foreign material
LOINC® Map
Order Code | Order Code Name | Order Loinc | Result Code | Result Code Name | UofM | Result LOINC |
---|---|---|---|---|---|---|
489615 | NGS JAK2 V617F/CALR/MPL | 489532 | Specimen Type | 66746-9 | ||
489615 | NGS JAK2 V617F/CALR/MPL | 489616 | JAK2 V617F Result | 43399-5 | ||
489615 | NGS JAK2 V617F/CALR/MPL | 489617 | JAK2 V617F % | % | 53761-3 | |
489615 | NGS JAK2 V617F/CALR/MPL | 489618 | CALR Result | 77174-1 | ||
489615 | NGS JAK2 V617F/CALR/MPL | 489619 | CALR % | % | N/A | |
489615 | NGS JAK2 V617F/CALR/MPL | 489620 | CALR Nucleotide | 48004-6 | ||
489615 | NGS JAK2 V617F/CALR/MPL | 489621 | CALR Amino Acid | 48005-3 | ||
489615 | NGS JAK2 V617F/CALR/MPL | 489622 | MPL Result | 75033-1 | ||
489615 | NGS JAK2 V617F/CALR/MPL | 489623 | MPL % | % | N/A | |
489615 | NGS JAK2 V617F/CALR/MPL | 489624 | MPL Nucleotide | 48004-6 | ||
489615 | NGS JAK2 V617F/CALR/MPL | 489625 | MPL Amino Acid | 48005-3 | ||
489615 | NGS JAK2 V617F/CALR/MPL | 489626 | JAK2 V617F/CALR/MPL Background | 62364-5 | ||
489615 | NGS JAK2 V617F/CALR/MPL | 489627 | Method | 49549-9 | ||
489615 | NGS JAK2 V617F/CALR/MPL | 489628 | References | 75608-0 | ||
489615 | NGS JAK2 V617F/CALR/MPL | 489629 | Director Review | 72486-4 | ||
Order Code | 489615 | |||||
Order Code Name | NGS JAK2 V617F/CALR/MPL | |||||
Order Loinc | ||||||
Result Code | 489532 | |||||
Result Code Name | Specimen Type | |||||
UofM | ||||||
Result LOINC | 66746-9 | |||||
Order Code | 489615 | |||||
Order Code Name | NGS JAK2 V617F/CALR/MPL | |||||
Order Loinc | ||||||
Result Code | 489616 | |||||
Result Code Name | JAK2 V617F Result | |||||
UofM | ||||||
Result LOINC | 43399-5 | |||||
Order Code | 489615 | |||||
Order Code Name | NGS JAK2 V617F/CALR/MPL | |||||
Order Loinc | ||||||
Result Code | 489617 | |||||
Result Code Name | JAK2 V617F % | |||||
UofM | % | |||||
Result LOINC | 53761-3 | |||||
Order Code | 489615 | |||||
Order Code Name | NGS JAK2 V617F/CALR/MPL | |||||
Order Loinc | ||||||
Result Code | 489618 | |||||
Result Code Name | CALR Result | |||||
UofM | ||||||
Result LOINC | 77174-1 | |||||
Order Code | 489615 | |||||
Order Code Name | NGS JAK2 V617F/CALR/MPL | |||||
Order Loinc | ||||||
Result Code | 489619 | |||||
Result Code Name | CALR % | |||||
UofM | % | |||||
Result LOINC | N/A | |||||
Order Code | 489615 | |||||
Order Code Name | NGS JAK2 V617F/CALR/MPL | |||||
Order Loinc | ||||||
Result Code | 489620 | |||||
Result Code Name | CALR Nucleotide | |||||
UofM | ||||||
Result LOINC | 48004-6 | |||||
Order Code | 489615 | |||||
Order Code Name | NGS JAK2 V617F/CALR/MPL | |||||
Order Loinc | ||||||
Result Code | 489621 | |||||
Result Code Name | CALR Amino Acid | |||||
UofM | ||||||
Result LOINC | 48005-3 | |||||
Order Code | 489615 | |||||
Order Code Name | NGS JAK2 V617F/CALR/MPL | |||||
Order Loinc | ||||||
Result Code | 489622 | |||||
Result Code Name | MPL Result | |||||
UofM | ||||||
Result LOINC | 75033-1 | |||||
Order Code | 489615 | |||||
Order Code Name | NGS JAK2 V617F/CALR/MPL | |||||
Order Loinc | ||||||
Result Code | 489623 | |||||
Result Code Name | MPL % | |||||
UofM | % | |||||
Result LOINC | N/A | |||||
Order Code | 489615 | |||||
Order Code Name | NGS JAK2 V617F/CALR/MPL | |||||
Order Loinc | ||||||
Result Code | 489624 | |||||
Result Code Name | MPL Nucleotide | |||||
UofM | ||||||
Result LOINC | 48004-6 | |||||
Order Code | 489615 | |||||
Order Code Name | NGS JAK2 V617F/CALR/MPL | |||||
Order Loinc | ||||||
Result Code | 489625 | |||||
Result Code Name | MPL Amino Acid | |||||
UofM | ||||||
Result LOINC | 48005-3 | |||||
Order Code | 489615 | |||||
Order Code Name | NGS JAK2 V617F/CALR/MPL | |||||
Order Loinc | ||||||
Result Code | 489626 | |||||
Result Code Name | JAK2 V617F/CALR/MPL Background | |||||
UofM | ||||||
Result LOINC | 62364-5 | |||||
Order Code | 489615 | |||||
Order Code Name | NGS JAK2 V617F/CALR/MPL | |||||
Order Loinc | ||||||
Result Code | 489627 | |||||
Result Code Name | Method | |||||
UofM | ||||||
Result LOINC | 49549-9 | |||||
Order Code | 489615 | |||||
Order Code Name | NGS JAK2 V617F/CALR/MPL | |||||
Order Loinc | ||||||
Result Code | 489628 | |||||
Result Code Name | References | |||||
UofM | ||||||
Result LOINC | 75608-0 | |||||
Order Code | 489615 | |||||
Order Code Name | NGS JAK2 V617F/CALR/MPL | |||||
Order Loinc | ||||||
Result Code | 489629 | |||||
Result Code Name | Director Review | |||||
UofM | ||||||
Result LOINC | 72486-4 |