laboratory diagnostic - biochemistry - Citric acide, urine, Non acidified 24hr urine collection 3ml. Mix the 24 hours urine sample before aliquoting in a test tube for referral. Store urine in a cool place during collection. Exclude any urinary tract infection and specify diuresis, The urine must be frozen within 4 hour after collection and must be sent in the frozen samples container, Spectrophotometry-F, ssso, todylaboratories®, bmn, code L16LD1121