Short‐term biological variation and Reference change values of urinary 8‐oxo‐7,8‐dihydro‐2'‐deoxyguanosine and 8‐oxo‐7,8‐dihydroguanosine

AIM: The DNA and RNA oxidative damage products urinary 8‐oxo‐7,8‐dihydro‐2'‐deoxyguanosine (8‐odGsn) and 8‐oxo‐7,8‐dihydroguanosine (8‐oGsn) have potential use in clinical practice. However, biological variation (BV) and reference change values (RCVs) have not been established. The aim of this study was to establish the short‐term between‐subject BV(CV(G))(,) within‐subject BV(CV(I)), and RCVs for urinary 8‐odGsn and 8‐oGsn. METHODS: First‐morning midstream urine specimens were collected from 20 apparently healthy subjects(ten males and ten females) on five consecutive days. 8‐odGsn and 8‐oGsn were measured using LC‐MS/MS, while urine creatinine (U‐Cr) was also measured to correct their results. A two‐level nested ANOVA was used to estimate the CV(I) and CV(G.) RESULTS: The values of CV(G) for 8‐odGsn, 8‐odGsn/U‐Cr, 8‐oGsn, and 8‐oGsn/U‐Cr were 31.2%, 39.6%, 35.3%, and 28.8%, respectively, while CV(I) for them were 40.5%, 9.0%, 33.5%, and 12.1%, respectively. The RCVs for 8‐odGsn, 8‐odGsn/U‐Cr, 8‐oGsn, and 8‐oGsn/U‐Cr were 112.5%, 26.7%, 93.7%, and 36.5%, respectively. CONCLUSION: BV and RCVs were firstly established for 8‐oxo‐dGsn and 8‐oGsn, and can be used in clinical practice.