Identification of a simple and sensitive microplate method for the detection of oversulfated chondroitin sulfate in heparin products

Heparin is a commonly implemented anticoagulant used to treat critically ill patients. Recently, a number of commercial lots of heparin products were found to be contaminated with an oversulfated chondroitin sulfate (OSCS) derivative that could elicit a hypotensive response in pigs following a single high-dose infusion. Using both contaminated heparin products and the synthetically produced derivative, we showed that the OSCS produces dose-dependent hypotension in pigs. The no observed effect level (NOEL) for this contaminant appears to be approximately 1 mg/kg, corresponding to a contamination level of approximately 3%. We also demonstrated that OSCS can be identified in heparin products using a simple, inexpensive, commercially available heparin enzyme immunoassay (EIA) kit that has a limit of detection of approximately 0.1%, well below the NOEL. This kit may provide a useful method to test heparin products for contamination with oversulfated GAG derivatives.