Abstract: In a method for detecting a glucagon-secretin family peptide in a sample, the sample is contacted with a cleaving agent capable of digesting the glucagon-secretin family peptide by cleaving a peptide bond of at least one aspartic acid within the glucagon-secretin family peptide and thereby generating a plurality of peptide fragments, at least one of the peptide fragments containing an N-terminal end of the glucagon-secretin family peptide. The peptide fragment that contains the N-terminal end of the glucagon-secretin family peptide is then detected using liquid chromatography and mass spectrometry. The amount of peptide fragment that contains the N-terminal end of the glucagon-secretin family peptide in the sample can then be quantitated using a calibration curve.

Abstract: Even when the specimen contains human granulocyte elastase in the form of a mixture of free elastase with an elastase-inhibitor complex or complexes, the present invention enables the total quantity of elastase in that specimen to be precisely detected. The inhibitor is added to free elastase to convert it into an elastase-inhibitor complex, whereby the quantity of elastase can be measured by immunoassay as the total amount including the previously existing elastase-inhibitor complex. It is possible to precisely measure the total amount of elastase in mucus collected from the cervical canal of a pregnant woman, sputum or a rinsed solution of bronchovesicular lavage in which free elastase is mixed with an elastase-inhibitor complex.