How do doctors diagnose polycythemia vera (PV)?
To diagnose PV, your doctor will perform a test called a complete blood count (CBC) to see if your number of red blood cells is higher than normal.
Your doctor may also test your blood to look for amounts of a hormone called erythropoietin. Lower-than-normal levels of this hormone can be a sign of PV. Doctors use genetic tests to identify the mutation in the JAK2 gene.