N-acetylcysteine interference of Trinder-based assays

Area of Science:

• Clinical Chemistry
• Pharmacology
• Toxicology

Background:

• N-acetylcysteine (NAC) is a widely used antidote for acetaminophen (APAP) overdose.
• Laboratory assays are crucial for monitoring patient status and guiding treatment.
• Potential interference of NAC with common laboratory tests needs to be understood.

Purpose of the Study:

• To evaluate the interference of NAC with Trinder-based chemistry assays.
• To assess NAC interference in patients treated for APAP overdose.

Main Methods:

• Tested NAC interference in Roche Diagnostics Trinder-based assays (creatinine, cholesterol, HDL-C, triglycerides, uric acid) and non-Trinder assays (BUN, glucose).
• Evaluated Sekisui LDL-C reagent.
• Conducted a retrospective chart review of APAP overdose cases to examine plasma creatinine levels before and after IV NAC administration.

Main Results:

• Triglycerides, cholesterol, and creatinine assays showed interference at lower NAC concentrations (570-790 mg/L).
• HDL-C and LDL-C assays demonstrated interference at higher NAC concentrations (1760-2900 mg/L).
• BUN and glucose assays showed no significant interference up to 10,000 mg/L NAC; minor creatinine inhibition was noted in patients post-NAC.

Conclusions:

• NAC interference with tested assays generally occurs at concentrations exceeding therapeutic levels.
• Clinical laboratory monitoring in patients receiving NAC should consider potential assay interference, though significant impact is unlikely at typical therapeutic concentrations.