Skip to main content


While certain signs and symptoms may indicate that a person has MF, a series of tests are needed to confirm the diagnosis. It is important to have an accurate diagnosis, as it helps the doctor to:

  • Estimate how the disease will progress
  • Determine the appropriate treatment

Some of these tests may be repeated both during and after treatment to evaluate the effectiveness of treatment.

Medical History and Physical Examination

Evaluation of an individual with suspected MF should start with a detailed medical history and a physical examination.The medical history should include information about the patient’s 

  • Cardiovascular risk factors, such as high blood pressure and diabetes
  • Past illnesses and injuries
  • Current and past medications and other treatments 
  • History of thrombosis (the formation or presence of a blood clot inside a blood vessel) or hemorrhagic events (loss of blood from damaged blood vessels)
  • Family medical history 
  • Current symptoms 

After the medical history, the doctor will conduct a physical examination. During the physical examination, the doctor may:

  • Listen to the patient's heart and lungs
  • Examine the patient's body for signs of disease
  • Check different organs of the body

Blood Tests

  • Complete Blood Count (CBC) with Differential: This test is used to measure the number red blood cells, white blood cells and platelets in a sample of blood. It also measures the amount of the iron-rich protein that carries oxygen in red blood cells (hemoglobin) and the percent of whole blood made up of red blood cells (hematocrit). People with MF often have abnormally low levels of red blood cells. White blood cell counts are usually higher than normal (called “leukocytosis”), but in some patients, the white blood cell counts may be lower than normal (called “leukopenia”). Platelet counts may be higher or lower than normal.
  • Peripheral Blood Smear: A procedure in which a sample of blood is viewed under a microscope. A pathologist examines the size, shape, and appearance of blood cells in the sample, and also checks for the presence of blast cells (immature blood cells). Blast cells are normally found in the bone marrow and are not typically found in the peripheral blood of healthy individuals. People with MF often have abnormal teardrop-shape red blood cells and immature blasts in the blood.
  • Blood Chemistry Profile: This blood test measures the levels of certain substances released into the blood by organs and tissues in the body. These substances include electrolytes (such as sodium, potassium and chloride), fats, proteins, glucose (blood sugar), uric acid and enzymes. The test findings indicate how well a person’s kidneys, liver and other organs are working. People with MF often have elevated serum levels of uric acid, lactic dehydrogenase (LDH), alkaline phosphatase and bilirubin. The doctor may also check the serum levels of erythropoietin, ferritin, and iron, as well as the total iron binding capacity.

Bone Marrow Tests

Your doctor tests your bone marrow to help confirm a diagnosis. Bone marrow testing involves two steps usually performed at the same time in a doctor's office or a hospital:

  • A bone marrow aspiration to remove a liquid marrow sample
  • A bone marrow biopsy to remove a small amount of bone filled with marrow

A pathologist studies the samples under the microscope and examines the chromosomes inside the cells. This is necessary to differentiate MF from other MPNs. Patients with MF have increased numbers of megakaryocytes that are also unusual in size and shape, and there is scarring of the bone marrow (fibrosis). 

Molecular Testing

These tests look for abnormal changes in the genes, chromosomes, proteins or other molecules within the patient’s cancer cells. They are used for diagnosis and treatment planning.

Cytogenetic Analysis (Karyotyping): This test is used to look for abnormal changes in the chromosomes of the cancer cells. Normal human cells contain 23 pairs of chromosomes, for a total of 46 chromosomes. Each pair of chromosomes is a certain size, shape and structure. In some cases of MF, the chromosomes of the cancer cells have abnormal changes that can be seen under a microscope, such as extra or missing chromosomes, or broken or rearranged chromosomes. Some patients with MF have a “complex karyotype,” which is when there are three or more unrelated abnormalities in the chromosomes.

Polymerase Chain Reaction (PCR): This is a very sensitive test used to detect and measure specific genetic mutations that are too small to be seen with a microscope. PCR testing essentially amplifies (increases) small amounts of specific pieces of DNA so that they are easier to detect and measure in a cell sample. It looks for the presence or absence of specific gene mutations. PCR testing can be done with blood or bone marrow samples.

DNA Sequencing: This term refers to a number of different laboratory tests that examine the exact sequence (order) of DNA. By comparing the sequence of DNA in cancer cells with the DNA in normal cells, doctors can find genetic changes that are unique to the cancer cells and may be driving the growth of the patient’s cancer. DNA sequencing can be done with blood or bone marrow samples.

Approximately 90% of patients with MF have a mutation of the JAK2, MPL, or CALR gene. The approximate frequencies of these mutations are:

  • JAK2 mutation — 60% 
  • CALR mutation — 20-35%
  • MPL mutation — 5-8%

About 10 percent of MF patients do not have a JAK2, MPL or CALR gene mutation. In these cases, the disease is referred to as “triple-negative” MF, and it is associated with a worse prognosis (outcome). Further study is needed to identify other gene mutations that may be involved. Over the last several years, numerous other gene mutations have been identified in patients with primary MF including the genes called CBL, LNK/SH2B3, ASXL1, EZH2, TET2, IDH1/IDH2, SRSF2, DNM3TA, SF3B1, SRSF2, and U2AF1. These mutations may occur in addition to JAK2, CALR or MPL mutations; a person with MF may have several of these mutations at the same time. Scientists are investigating the role that these and other mutations may have in the onset and progression of MF.

HLA Typing

HLA typing should be performed for patients who are candidates for an allogeneic stem cell transplantation. HLAs play an important role in the body’s immune response to foreign substances by helping the body distinguish its own cells from foreign cells. HLA matching is done prior to a donor stem cell transplantation to find out if tissues between the donor and the person receiving the transplant match.

Criteria for Diagnosing Myelofibrosis

According to the 2016 World Health Organization criteria for diagnosing primary MF, a diagnosis requires all 3 major criteria + at least 1 minor criteria.

Major Criteria

  1. Proliferation of abnormal megakaryocytes accompanied by fibrosis in the bone marrow 
  2. Exclusion of other diseases defined by World Health Organization criteria, such as essential thrombocythemia, polycythemia vera, BCR-ABL1+ chronic myeloid leukemia, myelodysplastic syndromes or other myeloid neoplasms
  3. Presence of JAK2, CALR, or MPL mutation or another clonal marker (gene mutation) such as genes ASXL1, EZH2, TET2, IDH1/IDH2, SRSF2, SF3B1, or the absence of reactive myelofibrosis 

Minor Criteria

Presence of at least one of the following, confirmed in two consecutive tests

  • Anemia not caused by another condition, or
  • White blood cell count greater than or equal to 11 × 109/L
  • Palpable enlarged spleen, or
  • Lactate dehydrogenase (LDH) level above upper normal limits, or
  • Presence of immature blood cells in the peripheral blood (called "leukoerythroblastosis")

Related Links