HScore for Hemophagocytic Lymphohistiocytosis Calculator

HScore for Hemophagocytic Lymphohistiocytosis Explanation and Clinical Context HScore is a validated clinical tool developed to estimate the probability of reactive Hemophagocytic Lymphohistiocytosis also known as secondary HLH. It integrates clinical findings laboratory abnormalities and bone marrow evaluation to produce a weighted score that correlates with the likelihood of HLH. The variables include the degree of fever known immunosuppression organomegaly number of cytopenias ferritin triglycerides fibrinogen serum aspartate aminotransferase and presence of hemophagocytosis in bone marrow.

Higher scores indicate a greater probability of HLH which is a life threatening syndrome characterized by uncontrolled immune activation. Accurate early identification is essential because HLH requires urgent immunosuppressive therapy. HScore assists clinicians in determining whether the clinical picture supports a diagnosis of reactive HLH especially in settings where the full HLH diagnostic criteria cannot yet be fulfilled.

Values above approximately 169 correspond to a high probability of HLH while lower scores suggest reduced likelihood but still require clinical correlation. Early diagnosis improves outcomes and HScore provides a quantitative structured assessment that supports decision making in acute care settings.