There is ongoing interest in discovering biomarkers to assess kidney graft function prior to transplantation and predict outcomes. , . Neutrophil Gelatinase-Associated Lipocalin (NGAL) is a biomarker which has been shown to be sensitive in detecting acute kidney injury (AKI) with a diagnostic level being 150ng/ml.
A retrospective study was designed to assess correlation between NGAL levels in serum of DBD/DCD donors immediately prior to retrieval and post-transplant kidney function.
The source of serum samples was the QUOD tissue bank and donor samples were selected according to recipients’ kidney function 12 months after transplant. In total 20 DBD and 20 DCD samples were analysed; half of the samples in each group had good function (GFR >50) and half had poor function (GFR <25).
Serum NGAL levels were measured using an ELISA assay.
Across the four sub-groups there was a 50:50 split of standard criteria (SCD) and extended criteria donors (ECD). 42.5% of all donors had an AKI diagnosed by serum NGAL levels (NGAL-AKI), but only 12.5% had an AKI based on serum creatinine.
In the group of kidneys with a poor 12-month function and NGAL-AKI, 66.7% (equal across DBD and DCD groups) were from ECD donors. In contrast, only 18.2% of kidneys that achieved good function at 12-months following NGAL-AKI were from ECD’s (20% in DBD’s and 17.7% in DCD’s).
A high proportion of deceased donors have an NGAL confirmed AKI despite having a ‘normal’ pre-donation serum creatinine level. ECD donor kidneys with AKI diagnosed by serum levels are more likely to have a poor outcome at 12 months.
(To carry this pilot study forward, the authors will investigate the benefit of serum NGAL testing in ECD donors. Power calculations suggest a minimum sample size of 80 patients in each arm would be required to provide statistically significant results with a power value of 90%.)