Laboratory Tests

Fasting or random blood glucose via finger-prick sample. This test is used to determine if your blood glucose level is within a healthy range; if you have symptoms suggesting hypoglycaemia or hyperglycaemia, or if you are pregnant. If you have diabetes, you may be required to monitor glucose levels several times a day.

Albumin in urine most often occurs when either the glomeruli or tubules in the kidney are damaged. Inflammation and/or scarring of the glomeruli can allow increasing amounts of protein to leak into the urine. Damage to the tubules can prevent protein from being reabsorbed. This test makes semi-quantitative measurement of albumin in the morning urine sample.

Chloride is an electrolyte. When combined with sodium it is mostly found in nature as “salt.” Chloride is important in maintaining the normal acid-base balance of the body and, along with sodium, in keeping normal levels of water in the body. Chloride generally increases or decreases in direct relationship to sodium, but may change without any change in sodium when there are problems with too much acid or base in your body. Chloride is taken into the body through food. Most of the chloride is absorbed by the gastrointestinal tract, and the excess is excreted in the urine. The normal blood concentration remains steady, with a slight drop after meals (because the stomach produces hydrochloric acid after eating, using chloride from blood).

Albumin is the most abundant protein in the blood. It keeps fluid from leaking out of blood vessels; nourishes tissues; and transports hormones, vitamins, drugs, enzymes, and ions like calcium throughout the body. Albumin is made in the liver and is extremely sensitive to liver damage. The concentration of albumin drops when the liver is damaged, when a person is malnourished, or if a person experiences inflammation in the body. Albumin increases when a person is dehydrated.

Alkaline phosphatase is an enzyme found in high amounts in bone and liver. Smaller amounts of ALP are found in the placenta of women who are pregnant, and in the intestines. Each of these body parts makes different forms of ALP. The different forms are called isoenzymes.

ALT is an enzyme found mostly in the liver; smaller amounts are also found in the kidneys, heart, and muscles. When the liver is damaged, ALT is released into the bloodstream, hence increasing the concentration that can be detected in a blood test. This often happens before more obvious symptoms of liver damage occur, such as jaundice (yellowing of the eyes and skin).

AST (aspartate aminotransferase) is an enzyme that is found mostly in the liver, but also in muscles. When your liver is damaged, it releases AST into your bloodstream. An AST blood test measures the amount of AST in your blood. The test can help your health care provider diagnose liver damage or disease.

When you breathe, you bring oxygen (O2) into your lungs and release carbon dioxide (CO2). Carbon dioxide in your blood is present in three forms: carbonic acid (H2CO3), CO2 dissolved in the blood, and bicarbonate (HCO3-), the predominant form. Bicarbonate is a negatively charged ion that is excreted and reabsorbed by your kidneys. Its function is to help maintain the acid-base balance (pH) and to work with sodium, potassium, and chloride to maintain electrical neutrality at the cellular level. Measuring bicarbonate gives an estimation of acid-base balance. This is usually sufficient, but measurements of gasses dissolved in the blood may be done if more information is needed. Bicarbonate may be measured with sodium, potassium, and chloride in an electrolyte profile as it is the balance of these that gives your doctor the most information.

Bilirubin is an orange-yellow pigment, a waste product primarily produced by the normal breakdown of haem, which is a component of a protein called haemoglobin. Haemoglobin is found in red blood cells and gives them their characteristic red colour and is used to carry oxygen around the body. Bilirubin is ultimately processed by the liver to allow its elimination from the body. This test measures the amount of bilirubin in the blood to evaluate a person's liver function or to help diagnose anaemia caused by excessive red blood cell destruction. The normal life-span of red blood cells in the circulation is 120 days. When they are broken down the haem is initially released from the haemoglobin and then converted to unconjugated bilirubin. The unconjugated bilirubin is not water-soluble so it is carried by proteins in the blood to the liver. Within the liver, the unconjugated bilirubin has sugars attached to form water-soluble conjugated bilirubin. This is secreted into bile and carried to the intestine where bacteria break it down, eventually producing the brown pigment that colours normal stools. A small amount (approximately 250 to 350 milligrams) of bilirubin is produced daily in a normal, healthy adult. Normally, small amounts of unconjugated bilirubin are found in the blood, but virtually no conjugated bilirubin is present. Both forms can be measured by the laboratory tests but total bilirubin result (a sum of these) is usually reported.