Investigation in patients with an absolute erythrocytosis.
| Stage 1 . | Stage 2 . | 
|---|---|
| CBC | Bone marrow aspirate/trephine | 
| Arterial oxygen saturation | Marrow karyotype | 
| Ferritin | BFU-E culture | 
| B12 | Oxygen dissociation curve (p50) | 
| Folate | Sleep study | 
| Creatinine | Lung function tests | 
| Liver function tests | Chest X-ray | 
| Uric acid | Echocardiogram | 
| Abdominal ultrasound | Erythropoietin receptor mutation analysis | 
| Serum erythropoietin | 
| Stage 1 . | Stage 2 . | 
|---|---|
| CBC | Bone marrow aspirate/trephine | 
| Arterial oxygen saturation | Marrow karyotype | 
| Ferritin | BFU-E culture | 
| B12 | Oxygen dissociation curve (p50) | 
| Folate | Sleep study | 
| Creatinine | Lung function tests | 
| Liver function tests | Chest X-ray | 
| Uric acid | Echocardiogram | 
| Abdominal ultrasound | Erythropoietin receptor mutation analysis | 
| Serum erythropoietin |