Macro-Aspartate Aminotransferase and Its Laboratory Detection: A Case Report

Area of Science:

• Clinical Chemistry
• Biochemistry
• Diagnostic Medicine

Background:

• Elevated enzyme activity in human blood serum often signals disease.
• Benign conditions, such as macro-enzymes, can also cause elevated enzyme levels.
• Macro-enzymes may lead to unnecessary invasive procedures, patient complications, and increased healthcare costs.

Observation:

• A 71-year-old asymptomatic female presented with persistently elevated aspartate aminotransferase (AST) levels.
• The patient was referred for further testing to investigate potential underlying liver disease.
• Diagnostic work-up included a polyethylene glycol (PEG) precipitation assay.

Findings:

• The polyethylene glycol (PEG) precipitation assay successfully identified macro-AST in the patient's serum.
• This diagnosis helped to avoid the need for a high-risk liver biopsy.

Implications:

• Physicians should consider diagnostic work-up for macro-AST in cases of isolated AST elevation without clinical signs of liver disease.
• Accurate diagnosis of macro-enzymes can prevent unnecessary, invasive, and costly medical interventions.
• Distinguishing between pathological and benign causes of enzyme elevation is crucial for appropriate patient management.