Results Agreement between estimating methods and the reference standard was highest
when using creatinine values measured 7–365 days before admission. During this interval,
the intraclass correlation coefficient (ICC) for the mean outpatient serum creatinine level
(0.91 [95% confidence interval (CI), 0.88–0.92]) was higher than the most recent outpatient
(ICC, 0.84 [95% CI, 0.80–0.88]; P< 0.001) and the nadir outpatient (ICC, 0.83 [95% CI, 0.76–
0.87; P< 0.001) serum creatinine. Using the final creatinine value from a prior inpatient …

Acute kidney injury (AKI) is defined and staged by changes in serum creatinine
concentration and requires accurate assessment of baseline kidney function for correct
classification. Quick, accurate and automatable methods for estimating baseline creatinine
are needed where manual adjudication is impractical. This study compared baseline
creatinine assessed by a panel of clinical nephrologists to surrogate estimation methods in
379 adults admitted to a tertiary referral centre. Patients were included if they had chronic …