Laboratory Features and Pathology of Cytokine Storm Syndromes.

The laboratory diagnosis of cytokine storm syndromes (CSSs), i.e., hemophagocytic lymphohistiocytosis (HLH) and macrophage activation syndrome (MAS), is often challenging. The laboratory features using routinely available tests lack specificity, whereas confirmatory testing is available in only few laboratories in the United States. The disease mechanisms are still largely unclear, particularly in adults. In this chapter, the pathogenesis of CSSs, their associated laboratory findings, and recommended diagnostic strategies are reviewed.