Which condition could lead to an increased level of plasma creatinine?

An increased level of plasma creatinine is primarily associated with diminished renal function, making chronic kidney disease the condition most directly linked to elevated creatinine levels. Creatinine is a waste product formed from muscle metabolism and is normally excreted by the kidneys. In chronic kidney disease, the kidneys are unable to effectively filter out creatinine from the bloodstream, leading to an accumulation of this substance in the plasma.

While liver disease, hyperthyroidism, and untreated diabetes can influence metabolic processes and overall health, they do not directly impair renal excretion to the same extent as chronic kidney disease. In liver disease, for instance, liver function primarily affects bilirubin and albumin levels rather than creatinine clearance specifically. Hyperthyroidism can increase renal blood flow and potentially lead to lower creatinine levels in some contexts. Untreated diabetes can lead to kidney damage over time, but it is the chronic state of kidney impairment that definitively elevates plasma creatinine. Thus, chronic kidney disease stands out as the most relevant condition for increased plasma creatinine levels.