Creatinine is a chemical compound used primarily to assess kidney function. Creatinine levels are measured in blood tests. Patients who come for treatment in Switzerland always have this test. Before the creatinine level is measured, the patient must prepare appropriately. Raised creatinine may indicate impaired kidney function and reduced loss of muscle mass.

Measuring creatinine is one of the basic diagnostic tests. It detects kidney dysfunction and is also required before medical imaging with a contrast agent. Find out more about the creatinine test and the causes of abnormal values.

When is creatinine measured?

Creatinine is an important parameter of kidney function. For this reason, the doctor measures creatinine when kidney dysfunction is suspected or being checked. This may be caused by acute or chronic kidney disease. Damage to kidney cells by toxins, or the breakdown of red blood cells or muscle cells, can also impair kidney function. Other reasons for measuring creatinine include:

  • metabolic diseases (e.g. diabetes mellitus)
  • collagenoses (connective tissue diseases)
  • high blood pressure (hypertension)
  • acute loss of volume (due to bleeding or loss of fluid)

The doctor measures creatinine in the blood (serum or plasma) using an enzyme-based method. It can also be measured in the urine (24-hour urine collection).

How is creatinine tested?

Creatinine is measured in blood, usually taken from a vein in the crook of the elbow. The test requires a little preparation from the patient, which is very important for the results to be as reliable as possible. Creatinine is a chemical compound that undergoes certain changes in the body, so you should come for the test in the morning, ideally between 7.00 and 10.00. The creatinine test is carried out on an empty stomach: the patient should eat for the last time before 18:00 the previous evening. There are no contraindications to the creatinine test.

Abnormal creatinine results

Raised creatinine indicates impaired kidney function. Results above the normal range may indicate acute failure (when the impairment is sudden and temporary) or chronic failure (when the impairment is persistent and usually progressive). High creatinine may result, for example, from drug-induced kidney damage, poisoning with organic or inorganic compounds, extensive injuries or dehydration. A high-protein diet or creatine supplements can also raise creatinine levels. Slightly higher levels are found in Black people.

Low creatinine is seen with loss of muscle mass (muscle atrophy). Values below normal may occur in emaciated people with severe liver disease, in underweight people with low skeletal muscle mass (e.g. after limb amputation), and during glucocorticoid therapy. Lower creatinine is also seen in pregnant women and older people.