Dinitrophenol (DNP) Fatality Associated with a Falsely Elevated Salicylate Level: a Case Report with Verification of Laboratory Cross Reactivity.

INTRODUCTION: 2,4-Dinitrophenol (DNP) is a known uncoupler of oxidative phosphorylation that clinically leads to hyperthermia, tachycardia, tachypnea, and metabolic acidosis. Intentional overdoses of DNP are often fatal. We present an analytically confirmed fatal case of DNP overdose with a falsely positive elevated salicylate concentration. We further explored this cross reactivity of DNP with two salicylate assays.

METHODS: Clinically relevant serial dilutions of DNP were prepared in drug-free serum and analyzed using two different colorimetric NADH/NAD-based analytical methodologies.

RESULTS: The enzymatic salicylate assay demonstrated a reproducible false elevation of salicylate starting at a DNP level of 100 mg/L while the EMIT-based methodology was without any such interference at the maximum concentration tested (150 mg/L).

CONCLUSIONS: DNP cross reacts with some salicylate assays. This knowledge is important for providers, as there are significant variations in the management of DNP versus salicylate toxicity.