US Patent 9689021 Method for measuring beta-lactam antibiotics

The present invention relates to methods for determining the concentration of a free beta-lactam antibiotic in a biological sample. In particular, the present invention relates to methods for measuring a free beta-lactam antibiotic in a biological sample, comprising the steps of: (a) providing at least one class C beta-lactamase, a functional fragment or variant thereof; (b) providing at least one biological sample; (c) contacting said at least one class C beta-lactamase with said at least one biological sample; and (d) determining the concentration of said free beta-lactam antibiotic in said at least one biological sample.