title: Can urine dipstick be used as a surrogate for serum creatinine in emergency department patients who undergo contrast studies?
abstract: Contrast-induced nephropathy (CIN) is a complication associated with contrasted computed tomography (CT). Elevated creatinine (Cr) is often used to screen for CIN. This study evaluates dipstick urinalysis (Udip) detection of Cr > 1.5 mg/dL. If sufficiently sensitive, Udip results could then be incorporated into future rapid screening protocols for patients undergoing contrast studies. This retrospective record review evaluated all Emergency Department patients over 2 years with documented Udip and serum creatinine results. Patient demographics and pertinent past medical history were also collected. Data were collected on 2421 patient visits, with 241 having Cr > 1.5 mg/dL (9.9%). There were 923 patient visits with a negative Udip (38.1%). Sensitivity and negative predictive value for abnormal Udip in detecting elevated creatinine were 85.5% and 96.2% (p < 0.01), respectively. Thirty-five patient visits (among 26 patients) had negative urine dip and Cr > 1.5 mg/dL, but each reported at least one of the following at triage: prior renal disease, hypertension, diabetes, congestive heart failure, or age > 60 years. Udip is a sensitive screening test, but alone is not accurate enough to predict patients at potential risk for CIN (Cr > 1.5 mg/dL). However, combining Udip results with risk factor screening may allow a rapid method for predicting which patients may safely undergo contrast CT scanning in the ED, but this needs prospective evaluation.
authors: Department of Emergency Medicine, University of California, San Diego Medical Center, San Diego, California, USA.
authors: Daniel
authors: D
authors: Firestone
authors: Adam
authors: A
authors: Wos
authors: James P
authors: JP
authors: Killeen
authors: Theodore C
authors: TC
authors: Chan
authors: Kama
authors: K
authors: Guluma
authors: Daniel P
authors: DP
authors: Davis
authors: Gary M
authors: GM
authors: Vilke
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood / Q000652:urine; D000075202:Contraindications; D003287:Contrast Media / Q000009:adverse effects; D003404:Creatinine / Q000097:blood*; D004636:Emergency Service, Hospital; D005919:Glomerular Filtration Rate; D006417:Hematuria; D006801:Humans; D007674:Kidney Diseases / Q000517:prevention & control; D011237:Predictive Value of Tests; D011507:Proteinuria; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D016482:Urinalysis
chemical_list: D015415:Biomarkers; D003287:Contrast Media; D003404:Creatinine