All kit components of this kit are stable at 2 to 8°C. Any unused reconstituted standard should be discarded or frozen at -70°C. Standard can be frozen and thawed one time only without loss of immunoreactivity.
Haptoglobin (abbreviated as Hp) is a protein in the blood plasma that binds free hemoglobin released from erythrocytes with high affinity and removes it from the circulation to prevent kidney injury, and iron loss following hemolysis. Also, haptoglobin prevents bacteria from using the iron present in hemoglobin to grow, regulates the activity of many cell types of the immune system, and is an extracellular chaperone. Haptoglobin, as an antioxidant, has antibacterial activity and plays a role in modulating many aspects of the acute phase response. In addition, haptoglobin acts as a potent immunosuppressor of lymphocyte function and modulates the helper T-cell type 1 and type 2 (Th1/Th2) balance within the body. Haptoglobin plays a role in stimulation of angiogenesis and has highly potent cholesterol crystallization-promoting activity, also. Changes in the measured concentrations of haptoglobin in serum may help to assess the disease status of patients with inflammations, infections, malignancy etc. (increases) as well as in haemolytic conditions (decreases). Haptoglobin in its simplest form consists of two α- and two β-chains, connected by disulfide bridges. The chains originate from a common precursor protein which is proteolytically cleaved during protein synthesis. Haptoglobin exists in two allelic forms in the human population, so called Hp1 and Hp2; the latter one having arisen due to the partial duplication of Hp1 gene. Three phenotypes of haptoglobin therefore are found in humans: Hp1-1, Hp2-1, and Hp2-2. Hp of different phenotypes have been shown to bind hemoglobin with different affinities. Hp 1-1 is biologically the most effective in binding free hemoglobin and suppressing inflammatory responses associated with free hemoglobin. Hp 2-2 is biologically the least active, and Hp 2-1 is moderately active. The possible association of allelic polymorphism of haptoglobin with various pathologic conditions such as cardiovascular disease, autoimmune disorders, malignancy has been studied. Hp 2-2 phenotype presents characteristics of being an independent risk factor for cardiovascular disease (CVD) and more significant in diabetic CVD. In chronic kidney disease (CKD), due to various processes that take place simultaneously, the combined effect is different in the elderly and the young. The functional differences between the Haptoglobin phenotypes are most probably due to their antioxidative property and to macrophage activation with differential release of cytokines.