Macroamylase | Laboratory research

General Information

Macroamylasemia It is a condition in which there is an increase in serum amylase activity without the presence of clinical symptoms of pancreatic diseases. This is due to the association of serum amylase with large molecules (>200 kDa) that cannot be filtered by the kidney, which increases its half-life and serum amylase concentration by 6-8 times.

From a structural point of view, macroamylase is a circulating complex, where amylase is mainly bound to immunoglobulin and rarely to polysaccharide. Immunoglobulins included in the complex are represented by IgA and IgG. The composition of macroamylases is heterogeneous. Pancreatic type (P) and salivary type (S saliva) iso-amylases are obtained by adding macroamylase complexes in an acidic environment.

It is clinically important to distinguish between macroamylasemia and hyperamylasemia associated with other conditions. Unlike acute pancreatitis, macroamylasemia causes prolonged elevation of pancreatic amylase. This is usually the result of reduced enzyme clearance.

Macroamylase may occur in patients with hyperamylasemia and normal urine amylase levels, as well as in humans with normal serum and urine amylase levels.

The table shows the characteristics of different forms of hyperamylasemia:

Clinical symptoms are not directly related to macroamylasemia, although it is often found in studies conducted for the cause of abdominal pain.

Often, macroamylasemia is an early sign of the disease, as a specific marker, or may be a non-specific indicator at the beginning of dysproteinemic diseases.

Macroamylasemia is detected in patients with malabsorption syndrome, hepatitis, alcoholic, diabetic, metastatic liver damage, ectopic pregnancy, tubo-ovarian (ovary-appendix) abscesses, and others.

Incidental findings of macroamylasemia may be associated with paraproteinemia caused by myeloma, lymphoma, or acquired immunodeficiency.

Patient preparation – The study is conducted on an empty stomach

Research material -  Venous blood

Referral norm – In case of norm, macroamylase is negative in serum.