Laboratory Tests and Ancillaries
Essential Tests
Essential
tests that should be requested include a complete blood count (CBC) with
differential and platelet count (in which leukocytosis, leukopenia, thrombocytopenia,
or thrombocytosis may be seen), peripheral smear, metabolic
panel including LDH and serum uric acid levels, liver function tests (LFTs), renal
function tests, serum erythropoietin (EPO), and serum iron tests.
Human
leukocyte antigen (HLA) typing is recommended for patients with myelofibrosis
when allogeneic hematopoietic stem cell transplant is being considered.
Coagulation
Tests
Coagulation tests are performed in patients who will
undergo high-risk surgery or those with elevated platelet counts and/or
splenomegaly or unexplained bleeding, to evaluate for acquired von Willebrand
syndrome and/or other coagulopathies. These tests include prothrombin time
(PT), partial thromboplastin time (PTT), and fibrinogen. Plasma von Willebrand
Factor Antigen (VWFA) measurement and Von Willebrand activity may be used if
initial screening tests (eg PT, PTT) are prolonged and cannot be corrected.
Biopsy
Bone Marrow Aspirate with Iron Stain and Biopsy
Bone
marrow aspirate with iron stain and biopsy is necessary for the demonstration
of fibrosis which is required for the diagnosis of myelofibrosis. Reticulin
stain is used to demonstrate bone marrow fibrosis and trichrome stain is used
to distinguish between myelofibrosis grades.
Molecular and Genetic Analysis
Molecular testing for JAK2,
CALR, and MPL mutations is recommended for the diagnosis of primary
myelofibrosis. Molecular testing using blood or bone marrow for JAK2 V617F mutation
is recommended in the initial workup and if negative, molecular testing for MPL
and CALR mutations is recommended. Multigene next-generation
sequencing (NGS) may be used to test for JAK2, CALR, and MPL mutations.
NGS is recommended for mutational prognostication once diagnosis of myelofibrosis is confirmed. Other clonal markers
include ASXL1, EZH2, RAS, TET2, IDH1, IDH2, SRSF2, and SF3B1 gene
mutations.
Myelofibrosis_DiagnosticsMultiplex Reverse Transcriptase Polymerase Chain Reaction (RT-PCR)
Multiplex RT-PCR is the preferred method to detect BCR::ABL1 transcripts and rule out CML.
Fluorescence in situ Hybridization (FISH)
FISH is performed on peripheral blood to detect BCR-ABL1 transcripts and rule out CML. It may also be used to identify myelodysplastic syndrome (MDS)- or MPN-associated abnormalities if unable to aspirate and examine bone marrow.
Imaging
Computed tomography (CT) scan of the abdomen and pelvis can be done to document the size of the liver and spleen.