Proposed use of MIRCA as a clinical tool in the management of SCD. Patient care algorithms are categorized as asymptomatic without treatment (A), with treatment (B), and symptomatic on treatment (C). In all cases, it is recommended to define an individual’s MIRCA OI baseline. For asymptomatic individuals, an increase in MIRCA OI during follow-up is recommended as an indicator to start a first-line therapy (A) or to optimize HU after starting therapy (B). For symptomatic individuals (C), stable or rising MIRCA OIs may indicate a second-line therapy beyond HU or CTF. For dropping OIs, other red cell function tests may be prioritized to understand and target the underlying cause behind symptomatic disease (eg, adhesion microfluidics for increased red cell adhesion, viscometry, or hematocrit/viscosity ratio for high viscosity). Regardless of patient status, individuals should have OIs monitored at routine clinic visits and during acute crises.