Novel protein marker for early diagnosis of kidney failure

Researchers have found a novel protein marker that can give a rapid and early diagnosis of kidney failure in children undergoing heart surgery, reporting their results in this week’s issue of The Lancet.

Kidney failure can result after major surgery, stroke, severe infection, dehydration or adverse reactions to medicines. The incidence varies from 5% of hospitalised patients to 30–50% of patients in intensive care units. Currently, doctors use a marker called serum creatinine to diagnose kidney failure.

Prasad Devarajan (Cincinnati Children’s Hospital, USA) and colleagues looked at whether high levels of a protein called neutrophil gelatinase-associated lipocalin (NGAL) could give an early diagnosis of renal injury in a susceptible population. They took blood and urine samples from 71 children undergoing cardiopulmonary bypass surgery. 20 patients developed acute renal injury. Diagnosis using serum creatinine was possible only one to three days after the initial injury. However, testing for high concentrations of NGAL could diagnose kidney failure in two hours.

Professor Devarajan concludes: “Effective therapeutic measures for kidney failure are available but are often administered late because early biomarkers for kidney failure are not available. We found that NGAL represents a novel, sensitive, specific, and highly predictive biomarker for acute renal injury following cardiac surgery.”

In an accompanying comment Stefan Herget-Rosenthal (University Duisburg-Essen, Germany) states: “As with any novel biomarker, it is advisable not to generalise these results. Although impressive, it should be noted that the data apply solely to a small number of children with initially normal renal function who developed acute renal failure after cardiothoracic surgery in a single centre.”