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Clinical
Indications |
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Macroamylase
is a high molecular weight form of amylase. It
circulates as a complex with immunoglobulins, usually
IgA (70%) or IgG (30%). Due to its size, renal excretion
is impaired causing a persistently raised serum amylase.
It is a benign finding which is usually chronic, but may
be transient.
Macroaylase is found in 1% of patients with an amylase
in the reference range, 5% of patients with an elevated
amylase and 13% of HIV positive patients with an
elevated amylase.
It is important to identify macroamylase in order to
avoid unnecessary invasive and expensive tests. A
persistently raised total amylase should raise the
possibility of macroamylaseamia, especially in an
asymptomatic patient with negative imaging.
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