patients follow an indolent course presenting with symptoms evolving over days or weeks Any unexplained low hemoglobin level, typically accompanied by a reticulocytosis, should prompt consideration of a hemolytic anemia Triage Children with hemolytic anemia often present in a relatively compensated state; however, their clinical status can deteriorate rapidly Severe, uncontrolled hemolytic anemia can be fatal with patients succumbing to insufficient oxygen-carrying capacity and cardiovascular collapse Ongoing assessment of cardiovascular and neurologic status is crucial during the diagnostic evaluation and until the rate of hemolysis is controlled Hematology and the blood bank should be consulted early for patients with suspected hemolytic anemia Initial Assessment/H&P The history should focus on systemic complaints relevant to anemia and hemolysis such as fatigue, light-headedness or near-syncope, fussiness, irritability or feeding difficulties in young children, and dyspnea Probe for symptoms of a systemic autoimmune process, an immunologic disorder, or malignancy as these can be associated with AIHA Elicit any personal or family history of an intrinsic RBC defect or AIHA Attention to recent exposures including symptoms suggestive of a recent or concurrent viral illness, toxins (e.g., naphthalene-containing mothballs), and medications can also provide clues about possible triggers ( Table 93.3 ) Typical examination findings for patients with hemolytic anemia include jaundice/icterus, pallor, tachycardia in some cases accompanied by murmur from a high-output cardiac state, and mild hepatosplenomegaly Other findings such as lymphadenopathy or massive hepatosplenomegaly may suggest underlying infection or malignancy The presence of jugular venous distention, significant hepatosplenomegaly, gallop rhythm, respiratory distress, hypotension, or poor perfusion heralds imminent cardiovascular collapse Diagnostic Testing A basic approach to the evaluation of hemolytic anemia is presented in Figure 93.2 The initial laboratory evaluation should include a CBC and differential, peripheral blood smear, reticulocyte count, blood type and antibody screen (indirect antibody test, also known as an indirect Coombs test), direct antiglobulin test (DAT, also called a direct Coombs test), haptoglobin, serum electrolytes, BUN/Cr, and bilirubin level The goals are to identify a hemolytic anemia, prepare for transfusion in case the hemoglobin is critically low or falling rapidly, and narrow the differential of the causative mechanism Reticulocytosis is present in most cases but can be absent or delayed in up to 10% of patients Therefore, consideration of hemolytic anemia should not be eliminated based solely on a low reticulocyte count Distinguishing between an immune- and a non– immune-mediated hemolytic anemia is an essential first step to guide therapy The DAT uses broad-spectrum Coombs serum (IgG, IgM, and complement) to detect the presence