Blood Chemistry Definitions

Human blood is made up of many components. Blood tests given in medical facilities can check the levels of these components. When blood is drawn for testing, it is possible that not all or even many components are checked. Often, a doctor has an indication of what he's looking for, so he'll order that only certain blood chemistry components be checked. Other times, he may order a full blood workup to try to resolve a health issue.

Glucose

• Glucose is a kind of sugar in human blood. It is made when food is broken down after we eat it. Our bodies need this sugar to break down even further into a chemical that can be used by cells called ATP. A blood glucose or blood sugar level that is too high or too low can be an indication of illness or disease. Blood sugar that is too high is often linked to diabetes.

Bicarbonate

• Bicarbonate regulates the amount of acid that the body's cells receive. The amount of bicarbonate in the blood is affected by the function of the lungs and kidneys. Therefore, measuring bicarbonate can provide a clue for doctors about the possibility of disease or dysfunction in these organs.

Potassium

• Potassium affects muscle contractions. This includes skeletal muscle in the limbs as well as heart muscle. Therefore, potassium levels are measured to give an indication of potential heart problems, especially the heart's rhythm. Low potassium is linked to weakness in the skeletal muscle.

Sodium

• Sodium is an electrolyte that controls the movement of water in and out of the body's cells. Sodium must go in and out of the cells in order to facilitate the contraction of muscles, as well. Sodium levels can be low due to the loss of fluids from vomiting or diarrhea. For this reason, staying well-hydrated during physical activity or illness is vitally important. If sodium is too high or too low, this can initiate symptoms like seizures and weakness.

Blood Urea Nitrogen

• Blood urea nitrogen, or BUN, is measured in the blood to see how the kidneys are functioning. Urea is one of the body's waste products. The kidneys filter waste from the body and remove it in the form of urine. BUN can be affected by abnormal kidney function, loss of blood and loss of fluids.

Creatinine

• Creatinine is also related to how well the kidneys are functioning because it's another chemical that's filtered by them. Injury to the muscle and fluid levels can also affect how much creatinine is in the blood.

Chloride

• Chloride is an electolyte and is half of the chemical makeup of table salt together with sodium. Like sodium, chloride levels in the blood are directly tied to fluid levels in the body. If chloride levels are too low, this can prevent certain bodily functions and chemical reactions from occurring, which can give way to illness.