Potential biomarker to predict acute kidney injury earlier than current tests

Clinicians currently lack advance warning of acute kidney injury (AKI) for patients where kidney injury timing is unknown.

Now paediatric research published in the open access journal, Critical Care, has identified a potential biomarker to predict AKI earlier than current tests, opening a vital window for prevention of this life-threatening condition.

A US team led by Michael Zappitelli, Kimberly Washburn and Stuart Goldstein from Baylor College of Medicine/Texas Children's Hospital in Houston studied urinary neutrophil gelatinase associated lipocalin (uNGAL) levels in a prospective cohort of 140 critically ill children. They found that uNGAL was a good diagnostic marker for AKI development, with levels at least 6 times higher than control subjects.

The rise in uNGAL concentration occurred 48 hours before a jump in serum creatinine (SCr) levels. This is significant because SCr, currently the main AKI biomarker used in clinical settings, shows a reduction in renal function has already begun and even small SCr rises are independently associated with mortality. The authors suggest that uNGAL is a good diagnostic marker for early prediction of AKI when the timing of the kidney injury is unknown. However, they caution that urinary NGAL may not be a good predictor of AKI severity after a jump in SCr has occurred.

The authors found that children in the study with sepsis have higher uNGAL concentrations than those without sepsis, but the relationship between uNGAL and AKI was maintained. "The ultimate goal will be to have a biomarker panel in a urine dipstick format to rapidly assess biomarker threshold concentrations," Zappitelli says. It remains to be seen whether the results will be duplicated in adults, in whom a higher degree of chronic inflammation may also affect uNGAL levels.

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