Serum Lactate Dehydrogenase is Elevated in Ischemic Acute Tubular Necrosis but Not in Acute Rejection in Kidney Transplant Patients.

BACKGROUND

Serum lactate dehydrogenase (LDH) levels may help to distinguish ischemic acute tubular necrosis (ATN) from acute rejection after kidney transplantation.

METHODS

All kidney biopsies performed in the years 2010 to 2012 were reviewed. Serum LDH, creatinine level, clinical variables, and presence of donor-specific antibodies were recorded before the biopsy.

RESULTS

Overall 150 biopsies were included. Ischemic ATN was diagnosed in 45 biopsies and acute cellular-mediated rejection and/or antibody-mediated rejection in 59 biopsies, 38 of which were accompanied by ATN. Serum LDH was elevated in 23 (51%) of 45 cases with ischemic ATN versus 15 (14%) of 105 cases with other diagnoses ( P < .0001). Median serum LDH was 478 U/L (range 277-2018) for ischemic ATN and 372 U/L (range 191-748) for all other diagnoses ( P < .001). When delayed graft function or primary nonfunctioning grafts were caused by ischemic ATN, serum LDH was elevated in 58% of cases, but when caused by acute rejection, LDH was normal in 88% of cases ( P = .02).

CONCLUSIONS

There is a strong association between elevated serum LDH 1 to 3 days before performing kidney biopsy and the diagnosis of ischemic ATN after kidney transplantation, especially at the immediate posttransplantation period. Normal serum LDH at this period should raise a suspicion of acute rejection.