Acute kidney injury was a common clinical complication, and many diseases were associated with a high risk of occurrence of AKI. We explored the clinical utility of serum CAF, L-FABP and NGAL by constructing a diagnostic model for identification of ICU patients at risk for AKI and distinguish different etiologies of AKI.

This observational cohort study included one hundred patients who had been in ICU from the Second Affiliated Hospital of Zhejiang University School of Medicine between August 2020 and August 2022. Blood and urine samples were collected every 12 hours until 7 days. The time of staying with ICU less than 2 days were removed. CAF, L-FABP and NGAL was measured based on the platform of Chemiluminescent Immunoassay, and assessed the diagnostic value of the occurrence of AKI. By constructing an effective diagnostic model to provide effective clinical decision-marking for early intervention.

The observational cohort study included one hundred patients who were from the intensive care unit of the Second Affiliated Hospital of Zhejiang University School of Medicine between August 2020 and August 2022. AKI was defined according to the Kidney Disease Improving Global Outcomes (KDIGO) guidelines as renal function was suddenly decreased within 48 hours and serum creatinine increased at least 0.3mg/dL, or serum creatinine increased more than 1.5 times higher than baseline within 7 days, or urine volume less than 0.5mL/Kg per hour for 6 hours. The staging criteria of AKI as follows: stage I means serum creatinine higher than baseline between 1.5times and 1.9 times, or serum creatinine increased at least 26.5μmol/L, or serum creatinine increased more than 1.5 times higher than baseline within 7 days, or urine volume less than 0.5mL/Kg per hour for 6 hours; stage II means serum creatinine higher than baseline between 2.0 times and 2.9 times, or urine volume less than 0.5mL/Kg per hour for 12hours; stage III means serum creatinine higher than baseline 3.0 times, or serum creatinine higher than baseline 353.6μmol/L, or started renal replacement therapy. Patients who stayed in the ICU for less than 24 hours and whose serum creatinine had increased above normal reference range on the first day of ICU were excluded.

Collecting the blood and urine samples of the patients regularly every twelve hours, centrifuging samples in 3000rpm for 5 minutes, freezing at -80℃, all patients' clinical information should be recorded by name, age ,sex, BMI index, hypertension, diabetes, cardiac disease, and so on. All patients have written informed contents and this study was approved by the Second Affiliated Hospital of Zhejiang University School of Medicine.NGAL, CAF and L-FABP was measured by chemiluminescent immunoassay with Robust i1000.

Inclusion Criteria:

1. the serum creatinine was increased above reference range at first when patients were included intensive care unit;
2. renal dialysis and plasma exchange were never occured when patients were included in the study;
3. patients who were included in the study stayed at two days in ICU.

Exclusion Criteria:

1. patients who stayed in ICU for less than 24 hours;
2. the serum creatinine was increased above reference range before ICU admission;
3. kidney-related diseases were existed before ICU admission.

The objects of study are the patients from the intensive care unit of the Second Affiliated Hospital of Zhejiang University School of Medicine between August 2020 and August 2022.