Drug–laboratory interaction between beta-lactam antibiotics and the galactomannan antigen test used to detect mould infections

Several studies have demonstrated that piperacillin/tazobactam produces a false-positive result for the galactomannan antigen test. However, the most recent literature has demonstrated that this interaction is no longer a concern. There is little information regarding the drug–laboratory interaction with the generics of piperacillin/tazobactam or other broad-spectrum beta-lactams, such as ceftaroline, doripenem, imipenem/cilastatin, and meropenem. The purpose of this study was to determine if a drug–laboratory interaction exists with these antibiotics. Tests showed that one lot of imipenem/cilastatin by Hospira Healthcare India Private Limited produced a false-positive result for the galactomannan antigen test. All other medications tested, including piperacillin/tazobactam from seven manufacturers and imipenem/cilastatin by Hospira Inc., did not produce positive results. Since the reason for this drug–laboratory interaction with imipenem/cilastatin is unknown, more studies are needed to further investigate this interaction. Providers also should be educated of these findings: no drug–laboratory interaction with piperacillin/tazobactam and a possible drug–laboratory interaction with imipenem/cilastatin (Hospira Healthcare India Private Limited).