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ESR:CRP Ratio Useful for Marking Infection in SLE
Lupus; ePub 2018 Mar 16; Littlejohn, et al
The ratio of erythrocyte sedimentation rate to C-reactive protein (ESR:CRP) may provide diagnostic value beyond individual ESR and CRP levels in distinguishing flare vs infection in systemic lupus erythematosus (SLE) patients presenting with fever, a recent study found. Researchers performed a medical records review of hospitalizations (1997–2006) of SLE patients in the Michigan Lupus Cohort. Eligible hospitalizations were those in which patients presented with a temperature of >100.3°F or with subjective fevers as a presenting complaint at admission. Detailed demographic, clinical, and laboratory data were collected. They found:
- Among 557 SLE patients screened, there were 53 eligible hospitalizations (28 flares and 25 infections).
- Each unit increase in the ratio of ESR:CRP was associated with a 17% increase in the odds of fever being attributable to SLE flare compared to infection, when adjusted for white blood cell count, SLE duration, sex, race, and age.
- ESR and CRP were not individually associated with flare vs infection when modeled with their ratio.
Littlejohn E, Marder W, Lewis E, et al. The ratio of erythrocyte sedimentation rate to C-reactive protein is useful in distinguishing infection from flare in systemic lupus erythematosus patients presenting with fever. [Published online ahead of print March 16, 2018]. Lupus. doi:10.1177/0961203318763732.