Making the Diagnosis
Your doctor will ask for a blood sample that will be sent to the laboratory for a hemoglobin level. This measures the number of grams of hemoglobin per liter of your blood. Your blood will also be checked for levels of white blood cells, platelets, and various other blood components. The laboratory will also look at the size and shape of your RBCs.
The different levels and how the blood cells look can tell the doctor a lot about what's causing the anemia. For instance, low red and white cells suggest a condition involving the bone marrow. The doctor will then test for other conditions, depending on the results of your initial blood test.