Electrochemical Point‐of‐Care Test for Assessing Serum Paracetamol Concentration: Comparison With Traditional Methods and Detection of Concomitant Drugs

Rapid serum paracetamol (acetaminophen) concentration measurement is essential in suspected intoxication, but centralized laboratory analyses often delay initiation of antidotal therapy. We studied the feasibility of a novel electrochemical single‐walled carbon nanotube/Nafion‐based point‐of‐care (POC) method in detecting paracetamol in 99 suspected overdose patient serum samples. POC was compared with the standard photoelectric enzymatic method (PEM) and ultra‐high performance liquid chromatography–photodiode array and corona‐charged aerosol detector (UHPLC‐DAD‐CAD). We also analysed for 900 concomitant pharmaceuticals, drugs and chemicals in 197 samples with time‐of‐flight mass spectrometry to assess interference with paracetamol concentration measurements. Paracetamol concentrations measured with UHPLC‐DAD‐CAD ranged between 0 and 2100 μmol/L, with 19% above the therapeutic level (≥ 200 μmol/L). Comparing POC with UHPLC‐DAD‐CAD, the false positives and negatives were 10% and 15%, respectively, at concentrations ≥ 30 μmol/L. All POC method false negatives occurred at concentrations < 45 μmol/L. PEM showed 8% false positives and negatives compared with UHPLC‐DAD‐CAD. Other substances detected included caffeine (78%), antidepressants (41%), benzodiazepines (34%) and antipsychotics (28%). They did not interfere with POC concentration measurement. The novel POC method is promising for measuring serum paracetamol at relevant concentrations.