Hematology & Oncology confusion pairs
18 Hematology & Oncology topics students commonly mix up on Step 2 CK, each with the fastest separator, a side-by-side comparison, and a free practice question.
Step 2 CK pairs are in open beta while clinical review finishes. Spot an issue? Tell us.
- Iron deficiency anemia vs Anemia of chronic diseaseLow ferritin is the single fastest discriminator favoring iron deficiency anemia.
- Microcytic anemia workup vs Macrocytic anemia workupMCV threshold, below 80 versus above 100 fL, is the immediate workup branch point.
- HIT type 1 vs HIT type 2Platelet fall greater than 50 percent beginning around day 5 after heparin exposure is the key discriminator for type 2 HIT.
- Acute leukemia vs Chronic leukemiaBlast percentage 20% or higher on marrow or peripheral differential.
- Transfusion reaction acute hemolytic vs Transfusion reaction febrile non-hemolyticPresence or absence of hemolysis and hemodynamic instability.
- DIC vs TTPNormal PT and aPTT with MAHA points to TTP rather than DIC.
- ALL vs AMLAuer rods on peripheral smear or marrow point to AML.
- HUS vs TTPRecent bloody diarrhea with dominant acute kidney injury favors HUS.
- Hodgkin lymphoma vs Non-Hodgkin lymphomaReed-Sternberg cells on excisional biopsy identify Hodgkin lymphoma.
- ITP vs TTPSchistocytes with thrombocytopenia identify TTP rather than isolated ITP.
- Hemophilia vs Von Willebrand diseaseDeep joint or muscle bleeding points to hemophilia, while mucosal bleeding with low ristocetin activity points to von Willebrand disease.
- B12 deficiency vs Folate deficiencyElevated methylmalonic acid distinguishes B12 deficiency from folate deficiency.
- Multiple myeloma vs MGUSAny CRAB end-organ damage with a monoclonal protein separates multiple myeloma from MGUS.
- CLL vs CMLBCR-ABL positivity on molecular testing is the defining discriminator for CML.
- Hemophilia A vs Hemophilia BSpecific clotting factor assay, low factor VIII versus low factor IX, is the definitive 5-second discriminator.
- Sickle cell crisis vasoocclusive vs Sickle cell acute chest syndromeA new pulmonary infiltrate with respiratory symptoms is the single discriminator that converts pain crisis to acute chest syndrome.
- Warm AIHA vs Cold agglutinin diseaseDirect antiglobulin profile of IgG positivity versus C3-only positivity distinguishes warm from cold autoimmune hemolysis.
- Cryoglobulins vs Cold agglutininsComplement-only positive direct antiglobulin test with cold-induced hemolysis identifies cold agglutinin disease.