Fast Five Quiz: Hemophagocytic Lymphohistiocytosis Presentation and Diagnosis

Sarah K. Tasian, MD


June 16, 2020

Figure 1. Hemophagocytosis in the bone marrow.

The diagnosis of HLH is based on clinical criteria. Diagnostic criteria that were developed by the Histiocyte Society for HLH (HLH-2004 criteria) are the most commonly used. They include:

  • Fever: ≥ 7 days of a temperature of at least 38.5°C (101.3°F)

  • Splenomegaly: a palpable spleen > 3 cm below the costal margin

  • Cytopenias: Counts must be below the specified range in at least two of the following cell lines:

    • Absolute neutrophils (< 1000/µL)

    • Platelets (< 100,000/µL)

    • Hemoglobin (< 9.0 g/dL)

  • Hypofibrinogenemia or hypertriglyceridemia

    • Fibrinogen level < 1.5 g/L or greater than three standard deviations below the age adjusted reference range value or

    • Fasting triglyceride level > 2 mmol/L or greater than three standard deviations above the age-adjusted reference range value

  • Natural killer cell activity is low or absent

Learn more about the diagnostic criteria for HLH.


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