Basic Concepts in Clinical Biochemistry-A Practical Guide.7z

29.4 Reagents........................................

1.Olive oil emulsion (50%): Take equal parts of olive oil and 5% aqueous solution
of gum acacia and homogenize it.
2.Phosphate buffer, 0.1 M, pH 7.4.
3.Ethanol.
4.0.05 M NaOH solution.
5.Phenolphthalein (1%) alcoholic solution.

33.5 Procedure

1. Take two test tubes and label as test and control.


2. Add 0.4 ml of olive oil emulsion and 0.2 ml serum and 0.5 ml phosphate buffer to
   both the tubes.


3. Vortex the tubes and incubate the tube labelled as test at 37C for 24 h and control
   tube at 4C for 24 h.


4. Take out both the tubes and add 3 ml of ethanol to test and control tubes.


5. Vortex and add two drops of phenolphthalein to both the tubes, mix, and titrate
   both the tubes against 0.05 N NaOH solution until a pink color is observed. Note
   the volume of NaOH used.

29.6 Calculation

One Cherry Crandall Unit (CCU) is defined as 1 ml of 0.05 N NaOH required to
neutralize the free fatty acid liberated by the action of lipase on olive oil substrate at
37 C (pH 7.4), for a period of 24 h by 1 ml serum.

Lipase activity=mlserum¼

titration value TðÞC 1

Volume of sample

¼xCCU=ml

29.7 Clinical Significance...............................

Measurement of lipase activity in serum, plasma, or asceticfluid is used exclusively
for the diagnosis of pancreatitis. Normal level of lipase in serum is up to 0–160 U/L.
In acute pancreatitis the serum lipase activity rises within 2–10 h. Peak level at about
12 h and the value may return to normal within 48–72 h. In acute pancreatitis, the
lipase value increases 2–50-fold than normal. The increase in lipase activity is also
observed in obstruction of pancreatic duct by calculi or carcinoma of the pancreas. In
acute and chronic renal disease, there is increase in serum lipase activity.

118 29 To Estimate the Activity of Lipase in Serum