To Determine Serum and Urinary Amylase
Activity^28
28.1 Theory
Amylases are a group of hydrolyzing enzyme which hydrolyzes starch and glyco-
gen. There are two types of amylases:α-amylase (hydrolyzes randomlyα 1 – 4
glycoside links, also known as endoamylases, e.g., humanα-amylase) andβ-amy-
lase (hydrolyzesβ 1 – 4 glycosidic linkage). Salivary glands, pancreas, and fallopian
tubes show highest amylase activities, while ovaries, small and large intestine, and
skeletal muscle possess low activity of amylase.
28.2 Specimen Requirements
Serum is used which is stable for 7 days at room temperature and for 1 month at 4C.
For the blood test, patients should not eat or drink anything except water for 2 h
before the test. For the urine test, patients should drink enoughfluids during the 24 h
test to avoid dehydration. Collect 24 h urine or 1 h urine in container with preserva-
tive. Acidic urine makes amylase unstable; hence pH is adjusted to alkaline range
before storage at 4C.
28.3 Principle........................................
Iodine gives blue color with starch and its degradation products containing longer
chain linear polysaccharides. As the chain length shortens to less than 45 units, the
blue color changes through purple to red and brown until with less than 12 units no
color is observed. Amylase hydrolyzes starch to glucose and maltose; the time
required for the complete digestion of a certain amount of starch is determined by
periodic testing with iodine and, this time, is converted to Somogyi units.
#Springer Nature Singapore Pte Ltd. 2018
V. Kumar, K. D. Gill,Basic Concepts in Clinical Biochemistry: A Practical Guide,
https://doi.org/10.1007/978-981-10-8186-6_28
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