Hemophagocytic Lymphohistiocytosis: Likelihood Ratios

Introduction: A rare disease characterized by bone marrow macrophages (histiocytes) devouring red and white blood cells. Can be caused by certain viral infections (e.g. HIV, EBV), can be inherited, or can rarely be related to malignancy (lymphoma or leukemia).

Note that a big differential diagnosis is Adult-Onset Still's disease, which can also be associated with high ferritin and even secondary HLH.

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Tags: Hematologic Tag this Diagnosis.

The likelihood ratios of findings for Hemophagocytic Lymphohistiocytosis are listed below. See the left navigation bar to change the display.

Pre-Test Probability (Prevalence): %.	Post-Test Probability (Predictive Value): %.	Switch to display mode.
Note that calculating probabilities from more than one** finding is inherently inaccurate because findings are not independent. (For example, using two positive findings that share a common pathogenesis is likely to overestimate the true probability.)

Good Positive and Negative Likelihood Ratios
Finding	Result	+LR	-LR
[ + ] Decreased Glycosylated Ferritin	+ 0 -	4.2	0
<26% (of total ferritin) Study: Arthritis Rheum. 2008 May;58(5):1521-7. PMID: 18438821