PHƯƠNG PHÁP SẢN XUẤT MẪU NƯỚC TIỂU GIẢ ĐỊNH ỨNG DỤNG TRONG CHƯƠNG TRÌNH NGOẠI KIỂM TỔNG PHÂN TÍCH NƯỚC TIỂU

Abstract

Objectives: To study methods of producing simulated urine samples used in external quality assessment (EQA) program. The homogeneity and stability of producing samples was evaluated according to ISO GUIDE 35:2017. Methods: Ten parameters (density (Specific Gravity-SG), pH, glucose (GLU), protein (PRO), urobilinogen (URO), bilirubin (BIL), nitrite (NIT), leukocyte (LEU), keton (KET), blood (BLO)) of normal urine sample were adjusted to produce abnormal urine sample with predetermined characteristics. The sets of producing samples were evaluated for pre-analysis and assessment of homogeneity then divided into 2 lots and stored at different temperature conditions (2 - 8°C and -20°C). The long-term stability is assessed for 3 months at 6 periods of time comprising: 1, 2, 4, 6, 8 and 12 weeks. Sort-term stability was evaluated in the shipping conditions after 5, 8 and 10 days deliver to participant laboratories. Results: Two batches of simulated urine samples have been produced and evaluated for homogeneity and stability. All sample lots were homogenous (p value >0.05). All parameters of simulated urine were stable in 3 months at -20ºC (p> 0.05). However, at 2-8ºC LEU and BIL were stable in 6 weeks, URO was stable in 8 weeks, the other parameters (SG, pH, GLU, PRO, NIT, KET and BLO) were stable in 12 weeks. For short-term stability, parameters LEU, BIL and URO were stable during 8 days, the other parameters were stable over 10 days of transporting condition (p-value> 0.05). Conclusions: The procedure of simulated urine production has completely developed. The producing samples were reached the criteria for homogeneity and stability. Simulated urine was stable 3 months in storage (-20ºC) and 8 days in shipping condition. The producing samples are suitable to apply for urinalysis EQA program.