Background: Serum amylase is secreted by salivary glands and pancreas and is used for the diagnosis of pancreatic and parotid diseases. A number of factors can elevate the level of serum amylase including pancreatic diseases, salivary disease, gastrointestinal diseases, liver diseases, gynecologic disease, cholecystitis, peritonitis, renal failure, and drug induced.
Methods: We reported a case with abnormally elevated serum amylase, namely hyperamylasemia. Abdominal B-ultrasound, abdominal magnetic resonance imaging (MRI), parotid computed tomography (CT), gastroscopy, and colonoscopy were used to screen the causes of hyperamylasemia. Common serum tumor markers and serum biochemistry were detected to exclude some common causes. The amylase-creatinine clearance ratio (ACCR) was calculated for the patient.
Results: The average value of serum amylase were 881 U/L, which was significantly higher than reference value (10 - 220 U/L). According to ACCR value, the patient was diagnosed with macroamylasemia after the exclusion of some possible causes for elevating serum amylase.
Conclusions: When renal function is normal, serum amylase continues to increase and urine amylase is normal or decreased, macroamylasemia should be considered after the exclusion of pancreatic and parotid diseases. Macroamylasemia can not only be associated with autoimmune diseases, malignant tumors and other diseases, but also can be found in healthy population.