Immunoglobulin E

Human Immunoglobulin E (IgE) is a protein with a molecular weight of 190,000 daltons.  It is composed of two heavy chains and a pair of light chains linked together by disulphide.  A function of IgE is the immunity to parasites. In industrialized countries, IgE has also an important role in allergic reaction (type I hypersensitivity) … Continued


Transferrin is a protein with a molecular weight of approximately 79.6 kDa. It is the main protein of iron transport (III). It is synthesised mostly in the liver, but also in the choroid plexus of the brain. The transferrin plasma concentration is regulated by the availability of iron in the body: during iron deficiency, the … Continued

Rheumatoid factor

Rheumatoid factors are antibodies present in cases of rheumatoid arthritis, but also of Sjögren’s syndrome, scleroderma, dermatomyositis, Waldenström’s disease, sarcoidosis or even disseminated lupus erythematosus. Rheumatoid factors are generally used for the diagnosis of rheumatoid arthritis, and with anti-CCP antibodies, are the only biomarkers selected by the American Rheumatism Association for this pathology classification. These … Continued

Retinol Binding Protein (RBP)

Retinol-binding protein (RBP) is an unglycosylated protein synthesised by the liver. The role of RBP is to transport retinol (vitamin A) from the liver to the target tissues (retina, skin, etc.) in the bloodstream. This protein is then metabolised, filtered and reabsorbed in the kidney. RBP is a sensitive marker of undernutrition and the monitoring … Continued


Prealbumin, renamed transthyretin, is a non-glycosylated protein with a molecular mass of 34.98 kDa. This protein is synthesised in the liver. Prealbumin is a good indicator of the nutritional status of the patient. Its serum concentration will decrease in the case of liver disease, protein malnutrition, or in case of the acute inflammatory phase. A … Continued

Lipoprotein (a)

Lipoprotein (a) (Lp (a)) is a particle composed of lipids and proteins; a portion of this particle consists of phospholipids, cholesterol and a specific apolipoprotein, apolipoprotein B100, identical to LDL (low-density lipoprotein), which transports cholesterol.  The other part is an apolipoprotein (a) linked to apolipoprotein B100 by disulphide bridges. Apolipoprotein (a) (not to be confused … Continued


Haptoglobin is an alpha2-glycoprotein synthesised by the liver parenchyma. Its role is to irreversibly bind free haemoglobin in the blood, in order to preserve iron and prevent any potential damage to renal tubules which may occur further to the excretion of haemoglobin. Haptoglobin also has a role in controlling the local inflammation process. The haptoglobin-haemoglobin … Continued


Fibrinogen is a plasma protein precursor of fibrin, which polymerizes and becomes the main component of the fibrin clot. Fibrinogen is a protein of the inflammatory phase; its concentration increases during inflammation, infection, pregnancy and after trauma. A high level of fibrinogen is a significant risk factor for developing coronary artery and cerebrovascular diseases. A … Continued

Cystatin C

Cystatin C is a low molecular weight protein (13.3 kD) continuously produced by all nucleated cells. Its production is not affected by gender, muscle mass or the patient’s diet. The low molecular weight and the net positive charge of cystatin C allow it to be freely filtered by the renal glomerulus. It is mostly reabsorbed … Continued


C-reactive protein (CRP) is an α1-globulin predominantly synthesized by hepatocytes. It consists of five identical non-glycosylated polypeptide subunits, linked together non-covalently, forming a protein of about 115 kDa. It is composed of few or no carbohydrates. C-reactive protein is an important non-specific defence against inflammation, especially against infections. It is one of the most sensitive … Continued