Serum or plasma concentration of a substance measured by immunoassay (e.g., antibody or protein marker)

What This Test Measures

The test measures the concentration of a particular substance in your blood, such as an antibody, protein, or other marker. The method used is typically an immunoassay, which detects and quantifies these substances with high sensitivity. This can include markers for inflammation, infections, autoimmune diseases, or other physiological processes.

Why It Matters in Your Health

Identifying abnormal levels of this substance can help diagnose conditions like autoimmune disorders, infections, or certain cancers. For example, it may be used to track treatment progress or monitor chronic conditions.

Common Uses and Conditions

This test may be ordered if you have symptoms like fatigue, unexplained weight changes, or signs of an immune system issue. It can also be used in research, screening, or confirmatory testing for conditions where specific markers are known to play a role.

Sample Collection and Preparation

A blood sample is drawn from a vein, usually in your arm. The blood is then processed to separate serum or plasma, which is sent to the lab for testing. You may be asked to fast or avoid certain medications before the test, depending on the specific instructions from your healthcare provider.