Used in diagnostic assays to detect and quantify haptoglobin levels in biological samples, particularly in serum or plasma. Plays a key role in immunoassay development for monitoring hemolytic conditions, where haptoglobin binds free hemoglobin. Due to its high specificity, it serves as a reference standard in clinical research and diagnostic kit formulation. Also utilized in biomarker validation studies for inflammation, liver disease, and hemolytic anemia. Its consistent performance supports reproducibility in commercial and laboratory-developed tests.