Final answer:
A creatinine test is used to diagnose kidney disorders by measuring the efficiency of kidney function based on the level of creatinine, a waste product filtered out by the kidneys.
Step-by-step explanation:
A creatinine test is primarily used in the diagnosis of disorders related to the kidney. Creatinine is a waste product of muscle metabolism, specifically from a high-energy compound called creatine phosphate used in muscles. When the kidneys are functioning properly, they filter creatinine out of the blood and excrete it in urine. High levels of serum creatinine may indicate that the kidneys are not working efficiently and could signal renal dysfunction or failure. Kidney-related health issues can include abnormal fluid levels, electrolyte imbalances, and issues with blood pressure regulation. Moreover, kidneys are involved in the regulation of substances like sodium, calcium, and potassium, playing an essential role in maintaining homeostasis in the body.