Blood Tests to Check Your Metabolism

There are chemical compounds in your body responsible for metabolic reactions that allow your body to function properly and create energy. Discussions of these reactions fill textbooks and scientific journals, but in a very elementary summarized definition, metabolism is the building up and breakdown of compounds by specific enzymes through biochemical reactions to create energy in order to sustain life. When there is a metabolic dysfunction, it is likely due to a chemical imbalance caused by a specific condition, a genetic disorder or a diet. A basic metabolic panel blood test can be performed to determine the source of the problem. The test consists of eight anylates: glucose, sodium, potassium, chloride, bicarbonate, blood urea nitrogen and creatinine. This test may be ordered as part of a routine physical exam or might be ordered if your physician suspects you have a certain condition such as kidney disease or diabetes.


Glucose is a sugar that your body converts to energy through various metabolic processes such as in the citric acid cycle, glycolysis, glycogenolysis, gluconeogenesis and the pentose phosphate pathway. Your muscle, brain and red blood cells rely on the metabolism of glucose into energy. The glucose blood test, if abnormal, indicates either hypoglycemia (low blood sugar) or hyperglycemia (high blood sugar), which helps in the diagnosis of diabetes. Your doctor will sample your blood for glucose after he has you fast for eight to 10 hours prior. Normal fasting glucose blood levels are 70 to 99 mg/dL. Glucose levels at 126 mg/dL or higher are indicative of diabetes. However, your physician will collect more that one high blood glucose reading before diagnosing diabetes.


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Calcium is a mineral necessary for many metabolic functions. It allows you to contract you muscles, it keeps your heart beating and aids in blood clotting. The metabolic blood test for calcium only evaluates how much calcium is in your blood, not your total body calcium, which is primarily in your bones. The results of a blood calcium test will determine if your parathyroid gland and kidneys are functioning properly. The parathyroid gland is basically responsible for maintaining blood calcium levels. It can sense when blood calcium is low and will activate a hormone that will cause the bone to release calcium into the blood. Normal total blood calcium levels for an adult should be within the range of 9.0 to 10.5 mg/dL. If your calcium levels are above that range, you may have an overactive parathyroid gland. Alternatively, if your calcium levels are lower than normal, you may have an under-active parathyroid gland.


The electrolytes in your body that are typically measured by the metabolic blood panel are sodium, potassium, chloride and bicarbonate. Electrolytes are either positively or negatively charged minerals that flow in your blood. Diet directly affects your electrolyte levels, as well as your hydration status. Certain hormones are known to also affect electrolyte levels in your blood. Electrolyte tests analyzed individually cannot suggest a specific abnormality. Typically, to determine any metabolic abnormalities, the anion gap test will be used, which uses the combined results of the individual tests. The anion gap is the difference between positively charged cations, sodium and potassium and negatively charged anions, chloride and bicarbonate [anion gap = (sodium + potassium) – (chloride + bicarbonate)]. “Mosby’s Manual of Diagnostic and Laboratory Tests” lists a normal anion gap as 16 ± 4 mEq/L. Increased levels indicate that your body is more acidic. Diseases associated with increased anion gaps are diabetic and alcoholic ketoacidosis and lactic acidosis. Decreased levels indicated that your body is more alkaline due to several conditions that include ingesting too many antacids, chronic vomiting and metabolic alkalosis

Blood Urea Nitrogen and Creatinine

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The blood urea nitrogen (BUN) is used with the creatinine test to determine how well your kidneys are filtering waste products from your blood produced by various metabolic processes. Your physician may order these tests along with the electrolyte panel to get a full understanding of how your kidneys are functioning. A physician will look at the ratio between your BUN and blood creatinine level to determine abnormal levels. A normal ratio is between 10:1 and 20:1. Higher ratios are caused by restricted blood flow to the kidneys, dehydration, high protein diet or gastrointestinal bleeding. Lower than normal ratios may indicate malnutrition or liver disease.