Effects of hemolysis and lipemia on the COBAS® salicylate and acetaminophen assays compared to GDS assays

Objective We compared the COBAS® acetaminophen and salicylate assays (Roche Diagnostics) with the Stanbio GDS assays (Stanbio Laboratories) that are currently used in our laboratory with respect to interferences from hemolysis and lipemia. Methods Acetaminophen and salicylate were added into human serum with varying concentrations of hemoglobin or Intralipid® to generate a range of acetaminophen and salicylate concentrations. Then the COBAS® and GDS assays were used to measure the apparent drug concentrations; the H and L indices were measured to determine the extent of hemolysis and lipemia present in each specimen. Results Both hemolysis and lipemia have less effect on the COBAS® acetaminophen and salicylate assays than on the GDS assays. Conclusions The COBAS® assays for acetaminophen and salicylate are preferable to the current GDS assays in clinical toxicology laboratories.