The chemistry department is where blood plasma, serum, urine, and body fluid specimens are chemically analyzed. The department is responsible for the highest volume of tests in the clinical laboratory, and it is highly automated.
The chemistry department receives plasma specimens in green-top tubes and serum specimens in speckle-top, gold-top, and red-top tubes.
The most common tests in the chemistry department include the basic metabolic panel (BMP), comprehensive metabolic panel (CMP), lipid panel, and therapeutic drug monitoring (TDM).
The BMP measures eight analytes within blood plasma: glucose, calcium, sodium, potassium, chloride, CO2, creatinine, and BUN (blood urea nitrogen). The BMP is often used as a screening test. Abnormal results may indicate a wide variety of disorders. For example, elevated glucose levels may indicate diabetes. Elevated creatinine and BUN levels may indicate decreased kidney function.
The CMP consists of all the measurements from the BMP plus a liver (hepatic) function panel for a total of 14 analytes. The liver panel measures albumin, bilirubin, liver enzymes, and the total protein within the blood. Liver enzyme levels are important for detecting and monitoring disorders of the liver (e.g., hepatitis).
The lipid panel measures four analytes: total cholesterol, HDL, LDL, and triglyceride levels. Total cholesterol measures cholesterol in all lipoprotein particles. HDL, or "good cholesterol," measures the cholesterol in high-density lipoprotein particles. It is known as "good cholesterol" because it takes up excess cholesterol and transports it to the liver for removal. LDL, or "bad cholesterol," measures the cholesterol in low-density lipoprotein particles. It is known as "bad cholesterol" because it results in the deposition of cholesterol in blood vessels. Elevated LDL, total cholesterol, and triglycerides increase the risk of atherosclerosis. This panel is used to detect and monitor cardiovascular disease.
Therapeutic drug monitoring (TDM) determines the optimal drug concentration within blood plasma by analyzing peak and trough levels. By assessing the peak and trough plasma levels, the physician can adjust the dose of the drug being analyzed to optimize the therapeutic effect and avoid drug toxicity.
7. Atanassova, Vassia (Spiritia). "Blood testing tube with separated blood serum (yellow) and erythrocytes (dark red)." Wikimedia Commons, 05 July 2019, https://commons.wikimedia.org/wiki/File:Serum-separation_tube.jpg. Accessed 09 November 2020.
