Dipstick test	False positive	False negative
Bilirubin	Phenazopyridine (Pyridium)	Chlorpromazine (Thorazine), selenium
Blood	Dehydration, exercise, hemoglobinuria, menstrual blood, myoglobinuria	Captopril (Capoten), elevated specific gravity, pH < 5.1, proteinuria, vitamin C
Glucose	Ketones, levodopa (Larodopa)	Elevated specific gravity, uric acid, vitamin C
Ketones	Acidic urine, elevated specific gravity, mesna (Mesnex), phenolphthalein, some drug metabolites (e.g., levodopa)	Delay in examination of urine
Leukocyte esterase	Contamination	Elevated specific gravity, glycosuria, ketonuria, proteinuria, some oxidizing drugs (cephalexin [Keflex], nitrofurantoin [Furadantin], tetracycline, gentamicin), vitamin C
Nitrites	Contamination, exposure of dipstick to air, phenazopyridine	Elevated specific gravity, elevated urobilinogen levels, nitrate reductase-negative bacteria, pH < 6.0, vitamin C
Protein	Alkaline or concentrated urine, phenazopyridine, quaternary ammonia compounds	Acidic or dilute urine, primary protein is not albumin
Specific gravity*	Dextran solutions, IV radiopaque dyes, proteinuria	Alkaline urine
Urobilinogen	Elevated nitrite levels, phenazopyridine	—