Voulgaris A, et al. - Researchers evaluated serum Cystatin C (Cyst C) and neutrophil gelatinase-associated lipocalin (NGAL) levels in otherwise healthy obstructive sleep apnea syndrome (OSAS) patients and explored possible correlations with sleep parameters. In OSAS patients, after adjustment for age and BMI, findings suggested an association of serum NGAL levels with apnea-hypopnea index (AHI) and minimum oxyhemoglobin saturation during sleep, whereas there was a correlation of serum Cyst C levels with the percentage of time with oxyhemoglobin saturation < 90%, average, and minimum oxyhemoglobin saturation during sleep. Seemingly a significant contributor in the pathogenetic process of renal dysfunction in OSAS was sleep hypoxia. In otherwise healthy OSAS patients, a higher risk for latent kidney disease is indicated.