High kidney or creatinine level most often means that the kidneys are not functioning properly, states Mayo Clinic. However, other possible causes of high creatinine levels include dehydration, low blood volume and certain medications. Eating large amounts of meat or taking creatinine supplements may also cause creatinine levels to rise.
Creatine is formed in the body naturally when food is converted to energy, according to WebMD. Creatine is broken down into creatinine, which the body removes from the blood via the kidneys. This is passed out of the body through urination. Therefore, when the kidneys are not properly functioning, the amount of creatinine in the urine decreases but increases in the blood.
There are three different types of creatinine testing, states WebMD. The first type of test checks creatinine levels in the blood. Men normally have higher levels than women. The second type of test is called a creatinine clearance test. This test is done on the blood and the urine to measure how well the body removes creatinine from the blood. The third type of test is a blood urea nitrogen-to-creatinine ratio, which allows doctors to check for reasons such as dehydration that may be causing creatinine levels to be high.