Owren's buffer is used as the dilution medium in a fibrinogen assay. This implies the buffer's role is to

• A. Dilution medium
• B. Coagulation activator
• C. Anticoagulant
• D. Calibrator

Answer: (A)

The main idea is that Owren's buffer sets up a controlled, defined environment for the fibrinogen measurement by diluting the sample. In this assay, the plasma is brought into a consistent dilution with the buffer so that the amount of fibrinogen falls within a measurable range and the reaction conditions (pH, ionic strength, and overall milieu) are stable. The buffer itself does not provide a coagulation trigger, nor does it prevent coagulation, and it isn’t a standard with known fibrinogen concentration. Its single, crucial role is to serve as the dilution medium to ensure reproducible and accurate results.