Your blood acts as the main means of transport for several different substances in your body. By traveling through your blood serum, nutrients are able to reach their destination cells and waste products are carried away. Among the many chemicals commonly found in your serum are potassium and creatinine, both of which act as waste transporters to your kidneys, in addition to fulfilling other vital functions. Measuring your potassium and creatinine levels can reveal a lot about your current state of health.
Potassium and Creatinine Explained
Potassium is an essential mineral that your body uses to ensure proper contraction of the heart and other muscles, for acid-base balance and in protein synthesis. Within the blood, it also helps move nutrients into cells and carries waste products out. Creatinine is a product created from the breakdown of creatine, a chemical used in the energy transfer process that occurs within muscles. Once creatine has been used, it degrades into creatinine and is flushed from the muscles into the bloodstream. Your kidneys measure the potassium and creatinine in your blood. When these substances reach high levels, they are filtered out of the blood and excreted through your urine.
Normal Values of Potassium and Creatinine in Serum
Creatinine has a normal range of 0.6 to 1.2 mg/dL, the National Kidney and Urologic Diseases Information Clearinghouse notes. Females usually have lower creatinine levels, however, since they tend to have less muscle mass. Laboratories may also tend to have slightly differing ranges for what they consider normal. Potassium, on the other hand, has a normal range of 3.7 to 5.2 mEq/L. This is constantly regulated as potassium is lost through urine and sweat. The Food and Nutrition Board of the National Academy of Sciences has not set an upper limit for potassium consumption.
Testing Kidney Function with GFR
The glomerular filtration rate, or GFR, is a measure of how efficiently your kidneys are functioning. It determines how well your kidneys are filtering out waste materials by measuring the amount of creatinine within a blood sample. If your levels are slightly above normal, you probably won't feel any symptoms; however, even a slight elevation in creatinine can mean that your kidneys are not functioning optimally. This may also mean that they are not filtering out excess potassium properly.
Problems with Too Much Creatinine and Potassium
Normally, the kidneys filter out excess quantities of creatinine and potassium. When they fail to do so, medical problems may result. An excessively high amount of potassium in your body, also known as hyperkalemia, can lead to complications such as loss of consciousness, heartbeat irregularities, cardiac arrest, and changes in your muscle and nerve control. Too much creatinine, on the other hand, is in itself not a problem, but an indicator of a potential kidney disorder. These disorders can include a bacterial kidney infection, or pyelonephritis, damage or swelling in the kidney blood vessels, or glomerulonephritis, or cellular death in the kidney tubules. Reduced blood flow due to shock, dehydration or congestive heart failure can also cause creatinine levels to rise, as can prostate disorders and kidney stones.
References
- Lab Tests Online; Creatinine: The Test; March 2011
- Linus Pauling Institute; Potassium; December 2010
- MedlinePlus Medical Encyclopedia; Potassium in Diet; May 2010
- National Kidney Foundation: Glomerular Filtration Rate (GFR)
- National Kidney and Urologic Diseases Information Clearinghouse; They Kidneys and How They Work; February 2009
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