Lipase Test – Principle, Procedure, results

• The pancreas secretes an enzyme called lipase that aids in the digestion of fatty foods. High levels of lipase in the blood may indicate pancreatitis, a disorder characterised by the inflammation and enlargement of the pancreas.
• Other pancreatic difficulties, certain drugs, and diseases and disorders include kidney failure, cancer, and gallbladder and oesophagus troubles can all lead to an increase in lipase levels.
• To determine how much lipase is circulating in the blood, a blood test is performed. Having abdominal discomfort or other symptoms that could be caused by pancreatitis may prompt your doctor to perform a lipase test. For the purpose of diagnosing or ruling out further medical issues, your doctor may also recommend it.
• Acute pancreatitis is the most common pancreatic condition for which lipase testing is performed.
• Located just behind the stomach, the pancreas secretes hormones and enzymes that are both vitally necessary.
• Inflamed and enlarged pancreas is the hallmark of acute pancreatitis. Rapid onset and improvement after therapy characterise acute pancreatitis.
• When diagnosing chronic pancreatitis, a long-term illness that can lead to permanent pancreatic damage, lipase testing is occasionally employed.
• Intestinal obstruction or damage, liver disease, and diabetes are only few of the disorders for which the lipase test may be prescribed. Peritonitis, cystic fibrosis, and pancreatic neoplasms
• A lipase blood test quantifies the lipase enzyme produced in the pancreas.
• The pancreas secretes an enzyme called lipase that helps the body break down fats. The digestive process requires the aid of enzymes to properly digest and absorb food.
• It’s natural for the body to contain some lipase because of the enzyme’s vital function in fat digestion.
• In the presence of pancreatic inflammation or injury, more lipase is secreted. It is common for lipase levels in the blood to peak on the first day of symptom onset in people with acute pancreatitis. Within 14 days, lipase levels typically recover to normal.

What is a lipase test?

Lipase is a digestive enzyme that might be thought of as “digestive juice.” It aids in the breakdown of fatty tissue. To produce lipase, your body relies primarily on the pancreas, an organ situated behind and below the stomach. Salivary (spit) glands and the stomach both produce lipase.

A trace quantity of lipase in the blood is typical. A higher amount of lipase is secreted if your pancreatic cells are destroyed. High lipase levels in the blood could be an indicator of pancreatic illness. Pancreatitis is characterised by inflammation and swelling of the pancreas. In addition to aiding in the diagnosis of these illnesses, lipase tests can help rule out a number of others.

Lipase Test Objectives

• Finding bacteria that can make the exoenzyme lipase is the goal.
• Differential properties of Enterobacteriaceae, Clostridium, Staphylococcus, and Neisseria can be detected using a number of additional lipid substrates, such as maize oil, olive oil, and soybean oil.
• The Lipase Test can identify and quantify lipolytic bacteria, particularly in high-fat dairy products.
• Lipolytic capacity is also shown in a number of other types of fungi.

Lipase Test Principle

• Numerous foods contain considerable amounts of potentially hydrolyzable fats.
• The free fatty acids (FFA) liberated by fat hydrolysis may be responsible for an unpleasant flavour, or they may oxidise into compounds with disagreeable flavour characteristics.
• Numerous bacteria, yeasts, and moulds are capable of causing both hydrolytic and oxidative degradation of lipids when present in dietary samples.
• Microorganisms’ lipolytic enzymatic activity are one of the leading reasons of food degradation and restricted shelf life.
• Tributyrin Agar was initially developed by Anderson for the identification and enumeration of lipolytic microorganisms, such as Staphylococci, Clostridia, marine Flavobacteria, and Pseudomonas, as well as moulds in foodstuffs and other materials.
• Tributyrin is the most straightforward triglyceride found in natural fats and oils. Some microbes that do not hydrolyze other triglycerides or lipids with longer chain fatty acids hydrolyze it.
• Nonetheless, it is the substrate of choice for screening lipolytic microbes of potential importance in meals.
• Peptone and yeast extract supply nutrients to the organisms in the medium. The breakdown of tributyrin by microorganisms is evidenced by the presence of transparent zones surrounding lipolytic colonies in an otherwise opaque culture media.
• Lipolytic organisms make the medium transparent by converting the fat to butyric acid, which is water-soluble. The medium must have a homogenous turbid emulsion for the assay to be effective.

Media Used in Lipase Test

Tributyrin agar Media is Used for Lipase Test.

Tributyrin agar is a differential media that measures an organism’s ability to make lipase, an exoenzyme that hydrolyzes tributyrin oil. Lipases degrade lipids (fats). Tributyrin oil is a triglyceride, a type of lipid. Other lipase tests utilise other fat sources, including maize oil, olive oil, peanut oil, egg yolk, and soy oil.

Lipase permits organisms that make it to fragment lipids into smaller pieces. Glycerol and three fatty acids combine to form triglycerides. These are disassembled and transformed into a range of end-products that the cell can use for energy production and other operations.

In the agar, tributyrin oil produces an opaque solution. When an organism makes lipase and degrades tributyrin, a distinct halo appears around the locations where the organism has grown.

Composition

Preparation

1. Suspend 23 grammes in 990 millilitres of distilled or filtered water.
2. Add 10 ml of Tributyrin (FD081).
3. Mix and bring to a boil to completely dissolve the medium.
4. Autoclave at 15 pounds pressure (121 degrees Celsius) for 15 minutes to sterilise.
5. Cool to 45-50 degrees Celsius.
6. Combine well and pour into sterile Petri dishes

Note: For optimal lipase action, glass plates are suggested over disposable plates. Therefore, ONLY USE GLASS PLATES. DO NOT USE PLASTIC PLATES.

Lipase Test Procedure

1. Streak a single line of an organism on the tributyrin agar medium to inoculate it.
2. Immediately after streaking, incubate anaerobically in a gas-pak jar and transfer to an incubator maintained at 35-37o C for 24-48 hours; for aerobes, incubate the plate at 35-37o C for 24-48 hours.
3. Observe the free space surrounding the bacterial development.

Lipase Test Result Interpretation

• Positive Lipase test: clear zone around the bacterial growth
• Negative Lipase test: Lack of a clear zone around the bacterial growth indicates a negative Lipase test. 

Lipase Test Results of different organisms

Limitations of Lipase Test

• With non-glucose-fermenting rods, the opacity zones are small.
• Some microbes may need up to one week to generate a good lipase reaction.

Quality Control of Lipase Test

• Clostridium sporogenes ATCC 11437, positive, clear zone around the colony.
• Staphylococcus aureus ATCC 25923, positive, clear zone around the colony
• Clostridium perfringens ATCC 12924, negative, absence of clear zone around the colony

References

• https://www.sigmaaldrich.com/deepweb/assets/sigmaaldrich/product/documents/417/921/91015dat.pdf
• https://www.austincc.edu/microbugz/lipase_test.php#:~:text=Tributyrin%20agar%20is%20a%20differential,of%20lipid%20called%20a%20triglyceride.
• https://himedialabs.com/TD/M157.pdf
  https://www.testing.com/tests/lipase/
• https://www.healthline.com/health/lipase-test
• https://www.webmd.com/digestive-disorders/what-is-a-lipase-test
• https://medlineplus.gov/lab-tests/lipase-tests/