Creatinine

All information on the subject of creatinine

At a glance

Creatinine is a degradation product of the acid creatine. Creatine is needed for the energy supply of the muscles. In the kidneys, liver and pancreas, creatine is formed from the amino acids glycine, methionine and arginine. Every day, about 1.5 to 2% of the creatine is excreted as creatinine by the kidneys with the urine.

Not every person excretes the same amount of creatinine. The amount depends on his muscle mass and kidney function. The creatinine value can therefore be used to assess kidney function and to track the course of kidney disease.

For more information

For men, values between 0.5mg/dl and 1.1 mg/dl are considered normal, for women normal values are between 0.5mg/dl and 0.9mg/dl.

Too low creatinine levels have no medical significance.

If the creatinine levels are increased, this may indicate a disturbed function of the kidneys. Injuries to the muscles, muscular dystrophy or inflammation of the skin and muscles (dermatomyositis, polymyositis) are also possible causes. After exercise, seizures and after injections into the muscles (e.g. vaccinations), the values may also be increased.

The measurement value of urine creatinine is not considered in isolation, but in connection with other laboratory values. It is part of the creatinine clearance (clarification capability) and the albumin-creatinine clearance. Creatinine clearance records the filter and detoxification performance of the kidneys and is determined to better assess kidney function. Some diseases, such as diabetes mellitus or high blood pressure, often also lead to damage to the kidneys. Therefore, especially in such known pre-diseases, kidney values should be examined regularly. The creatinine clearance allows above all a relatively precise conclusion to the glomulary filtration rate (GFR), the most important parameter for assessing renal function.

Athletes, especially strength athletes, often take creatine as a dietary supplement to achieve an increase in strength endurance. A positive effect on muscle building and performance is possible, but not with every athlete. As a natural nutrient, creatine is mainly found in fish and meat, plant-based foods are less creat-containing.

Sources

  • Internisten im Netz: Kreatinin, URL: https://www.internisten-im-netz.de/mediathek/blutbild-erklaerung/kreatinin.html, Retrieved 18.06.2019
  • Huppelsberg, J. & Walter, K. (2013): Kurzlehrbuch Physiologie. Georg Thieme Verlag, 4th edition
  • Antwerpes, F.: Urinkreatinin, URL: https://flexikon.doccheck.com/de/Urinkreatinin, Retrieved 18.06.2019
  • Lahnsteiner, E. et al. (2004): Harnanalyse – praktisch zusammengefasst, 2. Auflage
  • Winemaker, C. & Pohanka, E. (2006): Sinn und Unsinn der Kreatinin-Bestimmung Nephro Script. 9. 6-10
  • Gressner, A. M. & Arndt, T. (2007): Lexikon der Medizinischen Laboratoriumsdiagnostik. Springer Verlag, 1st edition
  • Greten, H. et al. (2010): Innere Medizin Georg Thieme Verlag, 13th edition
  • Kuhlmann, U. et al. (2008): Nephrologie Georg Thieme Verlag, 5th edition
Status of information: Autumn 2019