肌酐 (jī gān) is a medical term referring to creatinine — a waste product generated from normal muscle metabolism and filtered out of the blood by the kidneys. The character 肌 means 'muscle', reflecting its origin in muscle tissue, while 酐 (gān) is a chemical suffix denoting an 'anhydride', indicating its molecular structure as a cyclic compound derived from glycine and other amino acids. Together, the characters literally signal 'muscle-derived anhydride'.

Clinically, serum or urine creatinine levels are routinely measured to assess kidney function — elevated levels often suggest impaired filtration, such as in chronic kidney disease or acute kidney injury. It’s commonly discussed in hospital settings, lab reports, and patient education materials about renal health. Unlike many Chinese medical terms borrowed from Japanese or Western languages, 肌酐 is a native calque, constructed using standard scientific character semantics rather than phonetic transliteration.