Question: A 45-year-old patient who went to the emergency room for general malaise, headache and progressive tiredness in recent weeks. On physical examination, a slight icteric dye of the skin and mucous membranes was detected and a 2-cm splenomegaly was felt under the costal margin. The analytical presents hemoglobin 8.6 g / dL, VCM 100 fL. The number of reticulocytes is high and anisopoikilocytosis is observed in the blood smear. In the biochemistry highlights LDH 1300 IU / L, bilirubin 2.2 mg / dL and undetectable haptoglobin. Which test is the most appropriate to guide the diagnosis of the patient? 
 Options:  <1> Fecal occult blood test. <2> Test of Coombs. <3> Determination of iron, cobalamin and folic acid. <4> Abdominal ultrasound. <5> Bone marrow aspirate.
2