Interference of N-Acetylcysteine (ANC) Therapy with Chemistry Tests

Patient selection: recent NAC therapy (for acetaminophen intoxication, other)

Detection: lower than expected analyte value

The NAC interferes with the Trinder reaction (hydrogen peroxide plus 4-aminophenazone) that generates a colored product.

Analytes that may be affected:

(1) creatinine

(2) triglycerides

(3) cholesterol

(4) lipase

(5) lactate

(6) uric acid

If the analyte is required clinically then an alternative assay should be used. For example, cystatin C or creatinine by the Jaffre reaction can be used for estimating the glomerular filtration rate (GFR).