Serum or plasma substance concentration (unspecified analyte) measured by immunoassay

What This Test Measures

An immunoassay detects your body’s presence of a particular substance—such as an antibody, hormone, or protein—by measuring its concentration in your blood. This test is often used to screen for conditions like infections, autoimmune diseases, or certain cancers. The exact substance being tested isn’t specified here, but it may relate to markers of inflammation, immune activity, or metabolic function.

Why It’s Ordered

Your healthcare provider may order this test to diagnose or monitor conditions like chronic infections, autoimmune disorders (e.g., rheumatoid arthritis), or to check for substances that could indicate organ dysfunction or exposure to toxins. It could also be part of a routine screening or follow-up for a known health issue.

Sample Collection and Preparation

Blood is drawn from a vein in your arm and sent to a lab. The sample is typically processed into serum (after clotting) or plasma (using an anticoagulant). The lab then analyzes the substance using a sensitive immunoassay technique to measure its concentration accurately.

Test Results Interpretation

Results are reported as a concentration value (e.g., in micrograms per milliliter or another unit). While reference ranges vary by lab and analyte, abnormal results may signal potential health concerns that require further evaluation, such as additional testing or medical advice.