Cholesterol
fS-Kol KL 2095
(in English fS-Chol)
Part study of the Lipid profile test package
Cholesterol plays a vital role as a building block for cell membranes and serves as the precursor for steroid hormones and bile acids. The liver serves as the central hub for cholesterol metabolism, where the synthesis of cholesterol, regulation of cholesterol-receiving receptors, storage, secretion into bile, and transportation to tissues are controlled.
Dietary cholesterol is transported via lipoprotein particles, called chylomicrons, through the lymphatic system and eventually reaches the bloodstream. In the bloodstream, cholesterol is carried by lipoprotein particles, with LDL particles transporting cholesterol to the tissues and HDL particles transporting cholesterol from the tissues back to the liver.
Cholesterol measurement is an integral part of diagnostic tests for dyslipidemia, which refers to abnormal fat values in the blood. Other essential tests include fS-LDL-C, fS-HDL-C, and fS-Trigly. To diagnose dyslipidemia accurately, it is necessary to conduct at least two tests on different days to determine the levels of total cholesterol, HDL cholesterol, LDL cholesterol, and triglycerides.
Indications
Monitoring the treatment of hypercholesterolemia. Assessment of risk for coronary artery disease.
Sample
1 mL of fasting serum, minimum 0.5 mL.
Storage and delivery
The sample can be refrigerated for up to a week, but for longer storage, it should be kept frozen. Delivery at room temperature, if it arrives within 24 hours.
Method
Photometric, enzymatic. Accredited method.
Turnaround time
1 – 2 weekdays
Reference ranges
Recommended value below 5.0 mmol/L.
The target value is determined according to the Dyslipidemiat Käypä hoito (Current Care Guidelines for Dyslipidemias) recommendation published on October 27, 2020, by the Finnish Medical Society Duodecim and the Finnish Association of Internal Medicine.
Interpretation of results
A high serum cholesterol concentration is a significant risk factor in the development of atherosclerosis. The most common cause of increased cholesterol is elevated LDL cholesterol, and it can be influenced by both hereditary and environmental factors.
Familial hypercholesterolemia (FH disease) is a hereditary condition that can lead to elevated cholesterol levels. It occurs due to a mutation in the gene responsible for encoding the LDL receptor, hindering the transfer of LDL cholesterol to the liver and resulting in elevated serum LDL cholesterol levels. The prevalence of FH disease in Finland is estimated to be around 1 in 600 individuals. Suspicions of FH disease arise when serum total cholesterol concentration reaches at least 8 mmol/l and LDL cholesterol concentration reaches at least 5 mmol/l.
Another hereditary form of hypercholesterolemia is familial combined hyperlipidemia (FCH), affecting 1-2% of the population. FCH is influenced by several gene mutations, and environmental factors such as age and overweight can also contribute to its manifestations. Overproduction of apoprotein B, associated with LDL cholesterol, or a dysfunction of lipoprotein lipase, leading to the accumulation of particularly harmful small and dense LDL particles in the bloodstream, is thought to be one cause of the lipid metabolism disorder. This is reflected in an increased serum apoB concentration rather than an increased LDL-cholesterol concentration.
More commonly, hypercholesterolemia is caused by common polygenic factors, which involve multiple genetic variants and environmental influences. Dietary habits play a significant role in this group. In the Finnish population, the hereditary factor apoprotein type E4 is more common than usual, occurring in about a third of Finns. People with ApoE4 are thought to have a special sensitivity to dietary cholesterol. Obesity and a low dietary fiber intake can also increase LDL cholesterol concentration.
Elevated cholesterol levels can also be associated with various medical conditions, including hypothyroidism, metabolic syndrome, nephrotic syndrome, biliary stasis, diabetes, gout, uremia, and pituitary insufficiency. Pregnancy and menopause can also cause cholesterol values to rise.
On the other hand, low cholesterol values are found in conditions such as hyperthyroidism, malnutrition, malabsorption, among vegetarians, iron deficiency anemia, vitamin B12 and folic acid deficiencies, malignancies, liver cirrhosis, and other chronic diseases.
Literature:
Dyslipidemiat, Käypä hoito-suositus, 14.12.2022. Suomalaisen Lääkäriseuran Duodecimin ja Suomen Sisätautilääkärien Yhdistys ry:n asettama työryhmä
Ravitsemustiede, Duodecim 2021 (toim. M. Mutanen, H. Niinikoski, U. Schwab, M. Uusitupa)
Inquiries
martin.tornudd@milalab.fi
Last update 8.8.2023
