A study found that a discrepancy between two common blood tests to assess the kidneys - creatinine and cystatin C - can signal serious health problems[1][2]. When the results of these two markers do not match, the risk of kidney failure, heart disease and death increases significantly[4]. Cystatin C is a more sensitive marker of glomerular filtration and can detect early stages of kidney damage where creatinine can be inaccurate[1][2]. This discrepancy between tests is particularly common in hospitalized and elderly patients[1]. Researchers recommend combining both tests for correct and early diagnosis, as relying on just one test may miss warning signs of renal dysfunction[1]. The results of both parameters must always be interpreted together with the patient's clinical condition[1].