Blood draw
Carnitine Differentiation
Carnitine fraction profile; fatty acid metabolism.
€ 116,00
All tests
Vitamins, minerals and amino acids · Blood
Carnitine, total
All the carnitine in the blood together; carnitine carries fatty acids to the energy factories of the cell.
At a glance
- Measured in blood
- In 1 test panel
- No special preparation
Explanation
Carnitine, total: what is measured?
Carnitine helps long fatty acids into the mitochondria, the tiny energy factories of the cell, so that energy can be made from fat there. The body makes carnitine itself in the liver and kidneys from the amino acids lysine and methionine; carnitine also comes from meat and dairy. Total carnitine is the sum of free carnitine and all carnitine bound to a fatty acid or amino acid residue (the acylcarnitines).
What can it detect?
- A carnitine shortage due to another disease or treatment, for example with kidney dialysis or with certain medicines
- Rarely: an inherited disorder of fatty acid transport or fatty acid breakdown, which usually causes symptoms in childhood
Result
What does the result mean?
Carnitine, total too high
A high value is usually caused by a carnitine supplement or a meat-rich diet. The value can also rise with reduced kidney function, because carnitine is excreted through the kidneys. No symptoms are known to go with a high value. A high value does not mean that the cells make more energy.
Carnitine, total too low
A low value fits a low intake, for example with a vegetarian or vegan diet; on its own this usually causes no symptoms, because the body also makes carnitine itself. An acquired shortage can develop with kidney dialysis, with long-term use of valproic acid (a medicine for epilepsy) or certain antibiotics, with severe malnutrition and with severe liver disease. An inherited carnitine deficiency is rare and usually causes symptoms at a young age, affecting the muscles or heart, or low blood sugar when ill or fasting. It has not been shown that a low value explains tiredness or muscle pain in adults.
After an abnormal result
With a low value, the GP looks at diet, kidney function and medicine use. With a clearly low value without an explanation, or with symptoms of the muscles or heart or low blood sugar when fasting, referral to an internist (specialist in internal medicine) or a specialized center for metabolic diseases follows.
Reliability
How reliable is the test?
For adults without symptoms, the meaning of an abnormal value has been little studied. The result is mainly meaningful when a metabolic disease is suspected, with dialysis or with medicines that lower carnitine, and is then assessed together with free carnitine and the acylcarnitine profile, not as a value on its own. In the Netherlands, inherited disorders of fatty acid breakdown are detected through the newborn heel prick screening; in adults, an abnormal value rarely points to one.
What can affect the result?
- A carnitine supplement or a meat-rich meal raises the value; a vegetarian or vegan diet lowers it without there being a disease.
- Reduced kidney function raises the value, whereas dialysis lowers it sharply.
- The result can only be interpreted together with free carnitine and the acylcarnitine profile; total carnitine on its own says little.
- Measurement methods and reference values differ between laboratories and are not standardized.
Who it is for
Who is the test useful for?
Useful for
The result is mainly meaningful when a metabolic disease is suspected, with kidney dialysis and with long-term use of medicines that lower carnitine. In adults without symptoms and with a varied diet, the result adds little. Even with tiredness or muscle symptoms, it has not been shown that the result explains anything or changes the management.
How common is it?
Inherited disorders of carnitine transport or fatty acid breakdown are rare. Of the best-known form, MCADD, on average 15 to 20 children are born in the Netherlands each year; they are detected through the heel prick. An acquired carnitine shortage mainly occurs in dialysis patients and with long-term use of valproic acid; Dutch figures on this are lacking.
RIVM, prenatal and neonatal screening (heel prick)
Drawbacks and risks
- A low value due to diet or medicines can wrongly be read as a disease and lead to unnecessary follow-up tests.
- A low value can wrongly explain tiredness or muscle symptoms, so that another cause is found later.
Get tested
Carnitine, total: test panels
Carnitine, total is part of these test panels. You order online and have your blood drawn at a collection point or collect the sample at home.
Evidence
Sources
This explanation is based on Dutch guidelines and independent information. It is general information, not a diagnosis. Discuss an abnormal result with your GP.
More about risks and resultsMore explanations
Other tests: Vitamins, minerals and amino acids
- AC/FC ratio
- Acylcarnitine
- Alanine
- Antibodies against intrinsic factor
- Arginine
- Calcium
- Calcium (albumin-corrected)
- Carnitine, free
- Coenzyme Q10
- Copper
- Folic acid
- Glutamic acid (urine)