Reagent for prothrombin time measurement, method for production thereof, and method for measurement of prothrombin time

A method for producing a reagent for prothrombin time measurement, comprising steps of:

• (A) forming a first liposome having a phospholipid layer, using a phosphatidylcholine compound, a phosphatidylethanolamine compound, and a phosphatidylserine compound;
• (B) forming a second liposome having a phospholipid layer of a different composition from that of the first liposome, using at least one phospholipid selected from the group consisting of a phosphatidylcholine compound and a phosphatidylethanolamine compound;
• and
• (C) allowing a tissue factor to associate with the phospholipid layer of at least one of the first liposome obtained in step (A) and the second liposome obtained in step (B).

A method for measuring prothrombin time, comprising steps of:

• (a) contacting a reagent for prothrombin time measurement with a sample of blood, thereby to obtain a measurement sample;
• and
• (b) measuring the prothrombin time of the measurement sample, wherein
• the reagent contains a liposome composition comprising a first liposome having a phospholipid layer, a second liposome having a phospholipid layer of a different composition from that of the first liposome, and a tissue factor, wherein
• the tissue factor is associated with the phospholipid layer of at least one of the first liposome and the second liposome;
• the first liposome comprises a phosphatidylcholine compound, a phosphatidylethanolamine compound, and a phosphatidylserine compound;
• and
• the second liposome comprises at least one phospholipid selected from the group consisting of a phosphatidylcholine compound and a phosphatidylethanolamine compound.