Amylase
Definition
An enzyme that breaks down starch and is present at high activity in saliva. The Phadebas press test and starch-iodine method detect salivary amylase activity as a presumptive indicator of saliva. Amylase is also present at lower levels in other body fluids, so elevated activity is presumptive rather than confirmatory.
- Enzyme function
- Breaks down starch
- Highest activity fluid
- Saliva
- Presumptive tests
- Phadebas press test, starch-iodine method
- Evidentiary weight
- Presumptive only, not confirmatory
Common questions
Why can a positive amylase test not be reported as confirmed saliva?+
Amylase is present at lower but detectable levels in other body fluids and even some non-biological sources, so a positive result establishes elevated amylase activity, not the unique presence of saliva. A confirmatory method targeting a saliva-specific marker is needed to finalise the call.
What does the Phadebas test actually measure on a stain?+
It uses a dye-linked starch substrate pressed against the stain; amylase in the sample cleaves the starch and releases a blue dye visible where activity is present, giving a quick visual screen for likely saliva locations before further testing.
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