Hematology
Hematology questions test a systematic approach to anemia, bleeding, and thrombosis. Candidates must classify anemia by mean corpuscular volume (microcytic, normocytic, macrocytic), then use iron studies, reticulocyte count, and vitamin levels to narrow the cause. Know the difference between iron deficiency and anemia of chronic disease. Understand the peripheral smear findings that signal urgency (blasts, schistocytes, teardrop cells). Master the approach to thrombocytopenia and to suspected hematologic malignancy (cytopenias, lymphadenopathy, night sweats). Know anticoagulation reversal principles.
Traps: treating iron deficiency without finding the source of blood loss; missing that a normal hemoglobin does not exclude early iron deficiency; confusing immune thrombocytopenia with bone marrow failure; ignoring schistocytes as a sign of microangiopathic hemolysis.
Worked example: a patient with microcytic anemia and low ferritin. The diagnosis is iron deficiency. The next step is not simply iron replacement but identifying the source of loss, particularly gastrointestinal bleeding in older adults. Replacement corrects the number; finding the source changes outcomes.
Rule of thumb: before treating any cytopenia, look at the reticulocyte count and the smear. A high reticulocyte count points to peripheral destruction or loss; a low count points to production failure.
Key concepts: anemia classification, iron studies, smear interpretation, thrombocytopenia approach, and anticoagulation reversal.