Background and aims Introduction: systemic lupus erythematosus (SLE) is one of most prevalent autoimmune diseases in critical care in the last years and is associated with many complications, the infections are an important cause of mortality which makes necessary a rapid and precise diagnostic approach.

Methods A retrospective study was conducted, 56 patients with SLE were admitted to the intensive care unit (ICU) at a University Hospital in Bogotá, Colombia, between 2008 and 2016. The average age was 40.7 years old (SD ±17.7 y/o), female sex was predominant (71% vs 29%). Correlation between procalcitonin and eosinopenia in patients with positive cultures in bivariate analysis was performed to identify if there was a possible association to include those variables in a logistic regression model to establish an association with positive cultures.

Results two variables consistently associated with positive cultures in the logistic regression model, which had adequate prediction parameters: procalcitonin ≥2.0 ng/ml (OR: 6.076; 95% CI 1.75 to 20.79, p=0.004), absolute count of eosinophil <30 cells/mm³ (OR: 3.45; 95% CI 1.01 to 11.7, p=0.047).

Conclusion These variables could guide clinicians in early identification of patients with SLE and infectious diseases as a cause of critical illness, leading to early antibiotic therapy to improve survival rates. These results should be evaluated prospectively in future studies to find the prediction power in the differentiation of flare and sepsis in this group of patients.