A chemistry screen is a blood test that measures the levels of several substances in the blood (such as electrolytes). A chemistry screen tells your doctor about your general health, helps look for certain problems, and finds out whether treatment for a specific problem is working.
Some chemistry screens look at more substances in the blood than others do. The most complete form of a chemistry screen (called a chem-20, SMA-20, or SMAC-20) looks at 20 different things in the blood. Other types of chemistry screens (such as an SMA-6, SMA-7, or SMA-12) look at fewer. The type of chemistry screen you have done depends on what information your doctor is looking for.
For more information about specific parts of a chemistry screen, see:
Why It Is Done
A chemistry screen may be done:
- As part of a routine physical examination.
- To help you and your doctor plan changes in your meal plan or lifestyle.
- To look for problems, such as a low or high blood glucose level that may be causing a specific symptom.
- To follow a specific health condition and check how well a treatment is working.
- Before you have surgery.