• creatine (n): Organic substance obtained from muscular tissue, by 1843, from French creatine, from Greek kreas “flesh, meat” (from PIE root *kreue- “raw flesh”) + chemical suffix -ine (2). Discovered 1832 by French physicist Michel-Eugène Chevreul (1786-1889) and named by him.

• -ine (suffix): Word-forming element in chemistry, often interchangeable with -in (2), though modern use distinguishes them; early 19c., from French -ine, the suffix commonly used to form words for derived substances, hence its extended use in chemistry. It was applied unsystematically at first (as in aniline), but now has more restricted use. The French suffix is from Latin -ina, feminine form of -inus, suffix used to form adjectives from nouns, and thus is identical with -ine (1).

2. In creatinine clearance: Creatinine is a chemical end product of creatine metabolism that is removed, or cleared, from blood plasma by glomeruli and is excreted in the urine.

In renal system: Quantitative tests: The clearance of creatinine was used as a measure of renal function before inulin was discovered; because this substance is found naturally in plasma, creatinine clearance is still widely used as an approximate measure of the GFR.

3. Blood: An anhydride of creatine, being the end product of creatine metabolism, found in muscle and blood and excreted in the urine.

4. Differences between “creatine” and “creatinine”:

• Creatine is very important for the body. It is an organic acid. It is a natural compound created in the body and is obtained from the diet through meat products. It helps the muscle tissues generate more energy, speeds up growth of muscles, helps combat neurological and Parkinson’s diseases, reduce diabetes and improves high-intensity exercise performance. It is used as a dietary supplement meant for improving athletic performance and muscle strength.
• Creatinine does not perform any vital function in the body. It is not an organic acid. However, Creatinine levels in the blood can help your doctor assess how well your kidneys are working. The test helps to diagnose certain diseases and to check for any issues and conditions with your kidney function. If the kidneys are not performing as they should, however, creatinine levels in blood can elevate. When tests report that amount of this compound is very high, a doctor usually carries out additional testing to ascertain the extent of the issues with a person’s kidneys.