When the results of the CBC are available, the total WBC, ANC, hemoglobin, and platelet counts should be scrutinized. Depletion of more than one cell line may indicate marrow failure similar to that seen after chemotherapy, with aplastic anemia, or with a leukemic process. A repeated CBC to confirm abnormal findings may help to avoid a more costly evaluation.⁸

Once neutropenia has been identified in a febrile child, an investigation for a possible infection must be undertaken. Because urinary tract infection (UTI) is a common source of infection, infants and children between the ages of 2 months and 2 years with unexplained fever should be assessed for this disorder.⁴⁷ Bladder catheterization should be avoided in neutropenic patients.⁴⁸ Of note, Moustaki et al49 documented a risk of subsequent abdominal abscess in febrile neutropenic patients who underwent suprapubic aspiration during evaluation for UTI. Some authors have questioned the need for routine chest radiography in examining the chemotherapy-induced febrile neutropenic patient.^50,51 Renoult et al⁵² analyzed the results of chest radiographies in febrile neutropenic patients with cancer. They found that 5% of patients had abnormalities on chest radiographs consistent with a bacterial infection. Other studies reported incidence rates of 3.7% to 6%.^53,54 In several studies, all pediatric patients with neutropenia and a fever and confirmed pneumonia had respiratory findings suggestive of the diagnosis on clinical examination.^54,55 The inability of the neutropenic host to form pus, which may prevent pneumonia from being seen as an infiltrate on radiograph, should also be considered.⁴⁶ As noted earlier, studies suggest that previously healthy neutropenic patients are not at increased risk for bacteremia; however, some authors recommend obtaining a blood culture as part of the evaluation.²¹