Cystatin C, Lipase, Vit D, Holo-TC

Cystatin C is a protein that is produced by all body cells and serves as a marker for kidney function. The laboratory value measures the concentration of cystatin C in the blood and provides a more accurate assessment of the glomerular filtration rate (GFR) than serum creatinine.

A Cystatin-C test is recommended for: • People with suspected kidney diseases or impaired kidney function • Patients with diabetes, high blood pressure or other risk factors for chronic kidney diseases • Older people, as kidney function decreases with age • Patients for whom creatinine values are unreliable (e.g. due to strongly fluctuating muscle mass)

The test serves for the early diagnosis and monitoring of kidney diseases. It is also used to calculate the GFR, especially in patients for whom creatinine is not informative.

An elevated cystatin-C level indicates reduced kidney function. Symptoms may include: • Swelling (edema) • Fatigue, nausea or loss of appetite • High blood pressure in chronic kidney disease A low value is generally unproblematic and indicates normal kidney function. What is the ideal time for testing? The test can be performed at any time of day and is independent of food intake. Repeated tests are often helpful in assessing kidney function.

Cystatin C is less susceptible to influences such as muscle mass or diet, which makes it a reliable marker for the GFR. • Combined tests with cystatin C and creatinine provide a more precise assessment of kidney function. • An increased concentration can also occur in thyroid diseases, which should be taken into account in the interpretation.

The testing can be carried out at any time of the day and is independent of food intake. Repeated tests are often helpful for the assessment of kidney function.

Vitamin D is a fat-soluble vitamin that is produced in the skin through sun exposure and is also obtained through the diet. The laboratory value measures the concentration of vitamin D to assess the body's supply status.

A vitamin D test is recommended for: People with muscle weakness or bone pain Persons with chronic fatigue or exhaustion People with low sun exposure (e.g. office work, living in northern regions) People with dark skin (reduced vitamin D production) Older people (declining skin synthesis) Pregnant and breastfeeding women Persons with osteoporosis or chronic diseases (e.g. autoimmune diseases, diabetes)

The test serves to detect a vitamin D deficiency or an overdose. Vitamin D is essential for calcium and phosphate metabolism and contributes to bone health, muscle strength, and immune defense. A deficiency can increase the risk of osteoporosis, infections, and chronic diseases.

A low value indicates a deficiency that can be due to insufficient sun exposure, improper nutrition, or diseases such as malabsorption disorders. Symptoms of a deficiency are: Bone and muscle pain Muscle weakness and risk of falls Increased risk of infections An elevated value, usually due to excessive intake of vitamin D supplements, can lead to nausea, confusion, and calcium deposits in organs.

A test is possible all year round, but is particularly useful in winter and spring when the body's own stores are depleted due to lack of sun exposure. Persons with risk factors or symptoms of deficiency should be tested regularly. The test can be carried out at any time of the day and is independent of food intake.

Vitamin D is taken in two forms: D2 (ergocalciferol) from plant sources and D3 (cholecalciferol) from animal sources or through sunlight. D3 is better utilized by the body. Supplementation should be done under medical supervision, as overdosing can lead to health problems. The body's own production of vitamin D depends on factors such as skin type, age, geographic location, and season.

Lipase is an enzyme that is mainly produced by the pancreas and is responsible for the breakdown of fat. The laboratory value measures the lipase concentration in the blood and is used to assess pancreatic function and diseases.

A lipase test is recommended for: • People with symptoms such as severe abdominal pain, nausea or vomiting • Patients suspected of having acute or chronic pancreatitis • Monitoring of patients after surgery or with chronic pancreatic diseases • Clarification of unclear upper abdominal complaints

The test serves the diagnosis and monitoring of pancreatic diseases, especially in acute pancreatitis, and the clarification of unclear abdominal pain.

A high lipase value often indicates: • Acute or chronic pancreatitis • Tumors of the pancreas • Diseases of the bile ducts such as gallstones A low value rarely has clinical significance, but can occur in severe pancreatic insufficiency. Symptoms with elevated values can be: • Belt-shaped abdominal pain • Nausea and vomiting

The testing should be carried out in case of acute complaints.

• Lipase is more specific for pancreatic function than amylase, especially in the diagnosis of pancreatitis. • Certain medications, such as corticosteroids or diuretics, can influence lipase levels. • Chronic alcohol dependence often increases the risk of elevated lipase levels.

Holo-Transcobalamin (Holo-TC) is the biologically active form of vitamin B12 that is bound to the transport protein Transcobalamin. The laboratory value measures the concentration of Holo-TC in the blood and provides early indications of a functional vitamin B12 deficiency.

A Holo-TC test is recommended for: People with non-specific symptoms such as fatigue, memory disorders or neurological complaints Patients with a normal or borderline vitamin B12 level, in whom a deficiency is suspected Persons with risk factors for vitamin B12 deficiency (e.g. vegans, elderly people) Patients with suspected pernicious anemia or malabsorption disorders

The test serves for the early detection of a vitamin B12 deficiency, before severe symptoms develop. It complements the classic vitamin B12 measurement and is particularly helpful in diagnosing functional deficiencies.

A low holo-TC value indicates a functional vitamin B12 deficiency, which can occur despite a normal serum B12 value. Symptoms are: Fatigue and concentration problems Tingling or numbness in the extremities Anemia or neurological disorders A normal value usually excludes a deficiency and makes further tests unnecessary.

The test is meaningful in case of non-specific complaints or in risk groups such as vegans and elderly people. Testing is also appropriate in case of suspected malabsorption or before starting supplementation.

Here is the translation: Holo-TC is a more sensitive marker than total cobalamin, as it only measures the biologically active form of vitamin B12. Alcohol abuse and medications can affect the Holo-TC level.