Significant elevations of serum amylase caused by macroamylase: Case reports and detection possibilities

Abstract

Background The presence of isolated elevated serum amylase levels can be caused by high molecular mass complexes. We describe 13 cases of hyperamylasemia detected in adult patients without clinical symptoms of a pancreatic disorder. Five of them were thoroughly examined using different tools for the detection of macrocomplexes. Methods We performed both screening and more advanced methods of macroamylase detection, including polyethylene glycol precipitation, sample storage at 4°C and separation by gel filtration. Results The presence of macroamylase in the suspected samples was confirmed by the methods described, except for the sample storage at 4°C. In this method, the enzyme activity did not decrease. The polyethylene glycol precipitation activity (% PPA) averaged 89.1% for amylase, whereas the control samples averaged 30.7%. Gel filtration chromatography confirmed an IgA macroamylase peak in three samples and an IgG macroamylase peak in two samples. Conclusion The presence of macroamylase should be suspected whenever the clinical history and condition of the patient do not match the measured enzyme value to avoid diagnostic errors and unnecessary invasive examinations. The presence of macrocomplexes is considered a benign process that may occur in apparently healthy individuals. Cooperation between clinicians and laboratory staff is necessary.

Macroamylasemia versus Hyperamylasemia

“…Macroamylase was confirmed in five of them by the polyethylene glycol precipitation (PEG) method, and the polyethylene glycol precipitation activity (%PPA) in suspected patients was 89.1% for amylase and 84.3% for pancreatic amylase. 2) The %PPAs in the control samples were 29.6% for amylase and 32.2% for pancreatic amylase. The %PPA for immunoglobulin G, immunoglob-ulin A 58.0%, and immunoglobulin M were similar in the suspected samples and controls.…”

“…1) As macroamylasemia is estimated to affect approximately 1% of the general population and 2.5% of people with hyperamylasemia, the possibility of misdiagnosis with pancreatitis is high; therefore, the objective of the following comments is to enhance the suspicion index. [2][3][4][5] Čásenská et al 2) studied 13 asymptomatic individuals with a mean age of 40.8 years with isolated macroamylasemia without pancreatic disease and normal renal function. Macroamylase was confirmed in five of them by the polyethylene glycol precipitation (PEG) method, and the polyethylene glycol precipitation activity (%PPA) in suspected patients was 89.1% for amylase and 84.3% for pancreatic amylase.…”

“…The %PPA for immunoglobulin G, immunoglob-ulin A 58.0%, and immunoglobulin M were similar in the suspected samples and controls. 2) The authors highlighted the macrocomplexes as benign processes in healthy individuals. 2)…”