IMPROVED MEASURING METHOD FOR PROSTATE SPECIFIC ANTIGENALPHA1-ANTICHYMOTRYPSIN COMPLEX

PROBLEM TO BE SOLVED: To increase specificity for a PSA(A prostate specific antigen)-ACT(α1- antichymotrypsin) complex, and to avoid interferece to detection caused by other substances, in the detection for the PSA-ACT complex in a subjected sample. SOLUTION: In a method for an immunoassay of a PSA-ACT complex in a subjected sample, the sample is brought into contact with at least one antibody or its fragment coupling specifically with the complex or its component, the antibody or its fragment is bonded to a solid phase or is bindable to the solid phase, and a test solution containing an alkaline chloride is used at least in the case of making the sample contact with the solid phase. A buffer system contains an alkaline chloride besides an ordinary buffer substance. A detection kit contains a PSA specific antibody and an ACT specific antibody in the condition that one hand of these antibodies is bindable or bonded to the solid phase, and that other hand has labeling. Detection reaction is set up by the labeling, and the buffer system works as a buffer solution.