Biomarkers EvaluationProspective Observational Study to Evaluate Biomarkers of Aminoglycoside Nephrotoxicity in Patients With Cystic Fibrosis

Inclusion criteria:

1. Males and females ≥ 18 years of age.
2. Documentation of CF diagnosis as evidenced by one or more clinical features consistent with the CF phenotype and one or more of the following criteria:

• Sweat chloride greater than or equal to 60 mEq/L by quantitative pilocarpine iontophoresis test.
• Two well-characterized mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene; or
• Abnormal nasal potential difference.

3. Hospitalized and initiated on systemic antibiotic therapy for treatment of an acute pulmonary exacerbation.
4. Willingness and ability to comply with study procedures and study restrictions.
5. Ability to provide written informed consent.

Exclusion criteria:

1. Chronic kidney disease defined by microalbuminuria (> 30 mcg/mg creatinine) or eGFR < 60 mL/min/1.73m2.
2. Receiving medications known to alter the tubular secretion of creatinine (e.g. trimethoprim, cimetidine).
3. Hospitalized for treatment of an acute pulmonary exacerbation or received intravenous aminoglycoside antibiotics within 3-months of study entry.