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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.
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. Other clonal markers include ASXL1,
EZH2, RAS, TET2, IDH1, IDH2, SRSF2, and SF3B1 gene mutations.
Multiplex Reverse Transcriptase Polymerase Chain
Reaction (RT-PCR)
Multiplex
RT-PCR is the preferred method to detect BCR-ABL1 transcripts and rule
out chronic myeloid leukemia (CML).
Fluorescence in situ Hybridization (FISH)
FISH
is performed on peripheral blood to detect BCR-ABL1 transcripts and rule
out chronic myeloid leukemia.
Other Tests
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 disease 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
Ristocetin Cofactor (VWF:RCo) activity may be used if initial screening tests
(eg PT, PTT) are prolonged and cannot be corrected.