The effects of paraquat dichloride on clinical chemistry measurements.

Although measurements in the clinical chemistry laboratory are routinely used to monitor renal and hepatic toxicity from paraquat, it is not known if paraquat, a strong oxidant, interferes with common laboratory tests. The authors analyzed the effects of paraquat (concentration range of 0 to 1000 mg/L) on the Beckman IDEAL and Technicon SMAC analyzers for 20 common analytes. Although 18 tests were unaffected by paraquat, creatinine values rose from 1.3 to 7.6 mg/dL on the SMAC and 1.3 to 3.0 mg/dL on the IDEAL. Also, LDH was unaffected, rising by 6 and 12% on the IDEAL and the SMAC, respectively. Values for these correlated positively with serum paraquat concentrations although little effect could be discerned at paraquat levels less than or equal to 10 mg/L. Thus, the magnitude of the effects were such that interference by paraquat with the measurements of creatinine and LDH can be considered insignificant in clinical circumstances.