Knowledge Check

Sort the tests (top) according to whether they should be ordered as first-line tests in all patients with polycythemia, as second line tests according to symptoms, or not at all (bottom):

Serum EPO
Sleep study
Serum ferritin
Renal function
SaO2
Liver biopsy
Neuro imaging
CXR
CBC
Cardiac troponin
Abdominal/pelvic imaging
Echocardiogram
Liver function
Jak2 mutation (if PV suspected)
Reticulocyte count
ANA
TSH
First-line tests
Second-line tests
Not indicated

Abbreviations: CBC, complete blood count; SaO2, arterial oxygen saturation; EPO, erythropoietin; CXR, chest X ray; TSH, thyroid stimulating hormone; ANA, antinuclear antibody.

True of false: in the primary care setting, where the probability of PV is low, clinical evaluation for secondary causes of erythrocytosis paired with a high erythropoietin level can rule out PV in most patients.

a
True
b
False

In a young patient with a family history of erythrocytosis in whom first line and second lines studies do not reveal a diagnosis, what 2 tests would you consider: