Neutrophilic Gelatinase Associated Lipocalin (NGAL) ≥39.1 ng/ml, a protein found in urine, might be very accurate for both diagnosing (LR+ of 20.73, 95% CI 11.38–37.38) and ruling out cystitis (LR- of 0.04, 95% CI 0.01–0.21), based on one study [51]. The gene discussed is LCN2; the disease is chronic cystitis.