• Should be diagnosed based upon clinical judgement and history in conjunction with a diagnostic score/criterion
  • Scoring systems available include:
HLH Diagnostic Criteria
  • Produced in 2004 by the histiocyte society
  • Developed for diagnosis of primary HLH in paediatric population
  • Frequently applied to adult population though poorly validated
H-score
  • Weighted criteria developed in 2014
  • Only validated for secondary forms of HLH in adults