Salivary Amylase
Definition
An enzyme secreted by the parotid, submandibular, and sublingual salivary glands that cleaves starch molecules. Its high concentration in saliva relative to other body fluids makes it the primary biochemical marker for saliva identification in forensic casework.
- Source glands
- Parotid, submandibular, sublingual
- Substrate
- Starch
- Forensic role
- Primary biochemical marker for saliva
- Test type
- Presumptive, not confirmatory
Common questions
How does a presumptive amylase test differ from a confirmatory test in this context?+
A presumptive test flags the likely presence of saliva quickly and cheaply but can give false positives from other sources of amylase activity, whereas confirmatory methods target saliva-specific markers more precisely before a result is relied on evidentially.
Why is amylase preferred over looking for epithelial cells alone when screening for saliva?+
Amylase activity can be detected even when very few buccal cells are present or recoverable from a surface, making it a more sensitive first-pass screen than microscopy for locating a saliva stain before DNA sampling.
Can amylase testing damage a stain for subsequent DNA analysis?+
Examiners generally sequence testing so amylase screening precedes or minimally disturbs the area reserved for DNA extraction, since the stain is often limited in size and both tests compete for the same material.
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