JAK2 Blood Test Results Interpreted


The JAK2 blood test is used with a serious of other testing methods to determine whether or not an individual’s bone marrow is overproducing blood cells. This condition is known as MPN, or myeloproliferative neoplasms. There are several MPNs that are associated with a mutation of the JAK2 gene, including the manufacture of too many red blood cells, too many platelets created, or even cells that may create scar tissues within the bone marrow.

The JAK2 blood test is typically ordered when there is evidence of increased platelet counts of high levels of hemoglobin. This is an acquired mutation, not an inherited one, and creates a specific protein that tells the body that cell growth needs to happen continuously.

The goal of treating JAK2 mutations is to inhibit its function. There is no medical consensus for a JAK2 diagnosis, however, even from the World Health Organization, so the end result of this blood test may be subjected to a lot of variability.

What Do My Test Results Mean?

Because the JAK2 blood test is used to detect a specific point mutation of a gene, the test results will either be positive or negative. A negative test means that the bothersome physical symptoms being experienced, such as unusual fatigue, joint pain, a pale appearance, or a loss of appetite are not being caused by the genetic mutation. Sometimes a negative test will be followed up with a different JAK2 test because some false negatives may occur.

A positive result means that this mutation has occurred. The medical provider will then begin to narrow down what the specific issue happens to be so a diagnosis can be achieved and a treatment plan developed. This is especially important if the mutation is causing scar tissues on or within the bone marrow as this can develop into a very serious version of leukemia.

It is possible to have the JAK2 gene mutation and not experience any symptoms for several years. If symptoms are similar to those with severe anemia, however, and blood test results all appear to be normal, a medical provider may assume the presence of a mutation even if the test results do not indicate as such.

A bone marrow biopsy may be necessary to determine which specific MPN is present and how severe the MPN happens to be. Many laboratories do not have the capabilities to perform this specific blood test, so it is not uncommon to be waiting for several days to have test results received. This may be up to 10 business days, or 2 full weeks. Always follow-up with a medical provider if not results are received within this time frame.

Here’s What You Need To Know

The JAK2 mutation can only be detected in laboratories that are designed to perform molecular level testing. Only a reference laboratory can perform this test, which may affect which medical provider is performing this diagnosis. There may be health insurance complications that must be addressed because of this.

JAK2 blood testing is not ordered unless there are specific signs and symptoms which indicate there may be the presence of an MPN. It cannot be used as a screening test, so it is a rather rare blood test that is ordered. The average person in the general population is going to test negative if they were to be given this blood test.

There are times when a JAK2 blood test may be negative because the genetic mutation was missed. Medical providers which suspect an MPN may request a second blood test if the first one comes back as negative. Quantitative tests may also be ordered to monitor the cells that are being affected by this mutation show a positive test result be given.

Up to 95% of people with certain MPNs will test positive on the JAK2 test. Certain leukemias have also shown a positive test result. As few as 50% of people with certain MPNs, however, may have a positive test result, which is why it is difficult to have an accurate diagnostic protocol in place for this health condition.

Experiencing the symptoms of an MPN is what will trigger the ordering of the JAK2 blood test. Only a medical provider can interpret what the test results mean when compared to an individualized medical history. If there are any questions or concerns about specific test results, then speak with a medical provider about those results and what they may mean for personal health.