Creatinine is a substance that is produced by muscular activity when creatine phosphate is broken down. A creatinine level is the measurement of the amount of creatinine in a sample of blood. Normal creatinine levels for males are between 0.6 to 1.2 mg per dL of whole blood. For females, the normal range is between 0.5 and 1.1 mg per dL. Creatinine levels are used to determine kidney function.
The most common abnormality in a creatinine blood level is a change in kidney function. The kidneys are composed of around a million filters for each kidney, called nephrons. Each of these nephrons contains tubular structures that accomplish the filtering of waste materials and the re-absorption of necessary materials in the blood that passed through the nephrons. Most creatinine is normally filtered out along two structures called the glomerulus and proximal convoluted tubule, maintaining the low levels of creatinine in the blood. A rise in creatinine blood levels indicates that this filtration is not taking place, suggesting there is a problem with kidney function.
Creatinine levels can be affected by transient or non-disease factors that are not kidney malfunction. Bodybuilders, because of the excess of muscular tissue that creates creatinine, will typically have high levels of creatinine. Severe dehydration will cause higher than normal creatinine. Eating a great deal of meat just hours before blood is drawn can elevate creatinine levels. Some drugs will cause higher than normal creatinine blood levels. These causes are ruled out before a follow up test to determine the cause of elevated creatinine. Low creatinine levels may indicate muscular dystrophy or myasthenia gravis.
Elevated creatinine levels may indicate kidney disease or a pathology that interferes with kidney function, if non-disease factors are ruled out. One dangerous condition associated with hospital stays is acute tubular necrosis, dying nephron tissues, which can be caused by blood transfusion reactions, the dye used for some radiographic procedures or large doses of toxic antibiotics. Diabetes and chronic high blood pressure are common causes of diminished kidney function. Failures of the body’s immune system can lead to glomerulonephritis, the functional failure of the glomerulus, which can lead to kidney failure.
Preeclampsia is a condition during pregnancy, the cause of which is poorly understood. Elevated creatinine may indicate preeclampsia in pregnant women, especially women on their first pregnancy. Untreated preeclampsia can lead to eclampsia, a life-threatening seizure disorder. Elevated creatinine in conjunction with swelling of the hands and face is an early sign of preeclampsia. Later signs may include persistent headache, pain in the upper-right quadrant of the abdomen, inadequate urination, agitation and nausea.