Generality
Lipases are enzymes produced mainly by the pancreas and involved in the digestion of fats introduced with the diet.
Under normal conditions, the blood concentration of these enzymes is reduced; however, after damage to pancreatic cells (as happens, for example, in pancreatitis) or in the case of obstruction of the pancreatic duct (due to stones or neoplastic processes), a greater quantity of lipase is discharged into the blood stream, so an increase in the blood values of this parameter is observed.
What's this
Biological Role
In human serum a certain amount of lipase, fundamental enzymes for the digestion of lipids, is found. The blood concentration of these protein molecules is called lipasemia and increases in the presence of:
- Acute pancreatitis;
- Pancreatic carcinoma;
- Occlusion of the pancreatic duct;
- Peptic ulcer;
- cholecystitis;
- Viral gastroenteritis
- Inflammatory, infectious (see mumps) or tumoral salivary gland processes.
Due to its low molecular weight, lipase is almost completely filtered and metabolized in the renal tubules.
Why do you measure
Pancreatic lipase is an indicator of pancreatic health (precisely because this is the most active organ in terms of enzyme production) and surrounding organs .
The lipase examination is performed primarily as a support to the diagnosis and monitoring of acute pancreatic inflammation.
This analysis is also useful for monitoring or determining the presence of chronic pancreatitis or other pathologies involving the pancreas.
Occasionally, the lipase test is used in the diagnostic pathway and in the follow-up of cystic fibrosis, celiac disease and Crohn's disease.
When is the exam prescribed?
The lipase examination is indicated by the doctor in the presence of symptoms that lead to the suspicion of pancreatic disorders such as:
- Abdominal or back pain;
- Temperature;
- Loss of appetite;
- Weight Loss;
- Feeling of nausea;
- Difficulty in digestion;
- Particularly fatty or oily feces.
The determination of lipase in the blood can be prescribed periodically when the doctor wants to monitor the effectiveness of the treatment and to establish whether the parameter increases or decreases over time.
Associated examinations
The determination of lipases is often used in association with the amylase test : the two outcomes manage to give a fairly precise indication of whether the pancreas is involved in a pathological condition or not.
Normal values
- Normal lipase values range from 140 U / L to 200 U / L.
Note: the reference interval of the exam can change according to age, sex and instrumentation used in the analysis laboratory. For this reason, it is preferable to consult the ranges listed directly on the report. It should also be remembered that the results of the analyzes must be assessed as a whole by the medical doctor who knows the patient's medical history.
High Lipase - Causes
Since the lipase activity of the pancreas - compared to that of the other organs listed above - is particularly high, lipasemia is a good index for the diagnosis of acute pancreatitis ; the diagnosis of this condition, however, is traditionally placed through the determination of plasma amylase, another enzyme produced by the pancreas but less specific, because it derives largely also from the salivary glands.
The acute inflammatory process of the pancreas can elevate the serum lipase levels from 5 to 10 times above the maximum values of the normal range, and keep them at high levels for up to 5 - 7 days.
Compared to serum amylase, lipasemia tends to rise and fall with a slight delay.
The blood lipase examination can therefore be prescribed, often in conjunction with amylase, to diagnose or monitor acute and chronic pancreatitis or other pancreatic diseases.
The symptoms typically associated with pancreatic diseases are:
- Abdominal pain, often severe;
- Temperature;
- Loss of appetite;
- Nausea.
In summary, lipases can be increased in the following cases:
- Acute pancreatitis;
- Pancreatic lithiasis;
- Complications of acute pancreatitis (mesenteric infarction, peritonitis, pleuresia);
- Pancreatic duct obstruction;
- Affection of the biliary tract;
- Pancreatic cancer;
- Chronic alcoholism;
- Some drug therapies (including codeine, morphine, indomethacin, birth control pills, thiazide diuretics and cholinergic drugs).
Moderate increases in lipase may occur in other diseases, such as:
- Renal disorders;
- Inflammation of the salivary glands;
- Celiac disease;
- cholecystitis;
- gastroenteritis;
- Intestinal obstruction;
- Peptic ulcer.
Low Lipase - Causes
Lower than normal lipase values in serum may occur in the presence of permanent damage to pancreatic cells responsible for the synthesis of these enzymes and in some genetic diseases.
The pathologies that can be associated with the low concentration of lipases are:
- Chronic pancreatitis (the pancreas is not able to produce a sufficient amount of lipase, since its functionality is reduced);
- Cystic fibrosis (a disease that affects several organs, including the pancreas, compromising its functioning);
- Crohn's disease (inflammatory pathology affecting the intestine; in this case, the level of functionality of the lipase in the intestine is strongly compromised).
- Diabetes (affects various aspects of metabolism, including the production of an adequate level of lipase).
How to measure it
The determination of lipases involves the collection of a blood sample from a vein in the arm.
Preparation
The lipase test involves fasting for 8-10 hours prior to collection, both from drinks that are not water and from food. Furthermore, it is necessary to agree with the doctor the need to stop any drug therapies, which could alter the result.
Interpretation of Results
The value of lipasemia depends on the correct secretion of the lipase enzyme by the pancreas, which can be influenced by diseases that directly affect this organ, but not only.
The concentration of the parameter can depend, in fact, also on defects, pathologies or traumas of the neighboring organs, such as in the case of an abdominal trauma or an obstruction caused by stones that occlude the pancreatic duct.
High Lipase
High concentrations of lipase in the blood may indicate the presence of pathologies affecting the pancreas.
In the case of acute pancreatitis, there is often an increase in lipases up to 5-10 times the upper limit of the reference values (also called the upper limit of normality).
The increase in the parameter is observed within 4-8 hours from pancreatic damage and typically persists for 1-2 weeks.
The value of lipases can also be elevated in obstruction of the pancreatic duct and in other pathologies involving the pancreas, such as in inflammation due to stones.
Low Lipase
Low concentrations of lipase in the blood can indicate, instead, a permanent damage to the pancreatic cells responsible for their production. This can occur in chronic conditions affecting the pancreas, such as cystic fibrosis.
