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Fluctuations in serum amylase in patients with macroamylasemia
C K Sachdeva1, S Bank, R Greenberg
1Long Island Jewish Medical Center, Albert Einstein College of Medicine, Division of Gastroenterology, New Hyde Park, New York, USA.
Objective:
To report wide fluctuation of serum amylase in patients with macroamylasemia. It has generally been considered to remain constant.
Methods:
Over the past 16 y, 18 patients have been diagnosed with macroamylasemia in our GI department. Of these, four patients were followed up with serial serum amylase determinations for a period of less than 1-4 y. Serum amylase was measured by the "Phadebas amylase test." Serum macroamylase was measured by "PEG precipitation technique."
Results:
There was a wide fluctuation of serum amylase in three out of four patients. In the fourth patient, more persistent hyperamylasemia was noted during the shorter observation period.
Conclusion:
Marked fluctuation in serum amylase, ranging from 115 to 1160% in this study, may occur in patients with macroamylasemia. The reasons for these fluctuations are not clear but may be due to association-dissociation of amylase with serum proteins at variable time intervals. This fluctuation, especially when the amylase becomes normal (as in cases 1 and 3), may lead to confusion in differentiating macroamylasemia from other causes of hyperamylasemia.
Insights
Serum amylase levels can fluctuate significantly in patients with macroamylasemia, challenging previous assumptions of stability. This variability may complicate diagnosis and differentiate from other hyperamylasemia causes.
Area of Science:
- Biochemistry
- Clinical Diagnostics
Background:
- Macromolecular complexes of enzymes, such as macroamylase, can alter their pharmacokinetic properties.
- Previous understanding suggested serum amylase levels in macroamylasemia remain relatively constant.
Observation:
- This study investigated serum amylase fluctuations in four patients diagnosed with macroamylasemia over 1-4 years.
- Serial serum amylase measurements were performed using the Phadebas amylase test and PEG precipitation technique for macroamylase.
Findings:
- Three out of four patients exhibited wide fluctuations in serum amylase levels, ranging from 115% to 1160%.
- One patient presented with persistent hyperamylasemia during the observation period.
- Fluctuations, including normalization of amylase, can mimic other conditions causing elevated amylase.
Implications:
- The findings challenge the established view of stable serum amylase in macroamylasemia.
- Understanding these fluctuations is crucial for accurate diagnosis and avoiding misinterpretation.
- Potential association-dissociation of amylase with serum proteins may explain observed variability.