Alpha-1 Antitrypsin (A1AT)
Alpha-1 antitrypsin (A1AT) is a protein made mainly by the liver that helps protect your tissues, especially the lungs, from certain enzymes that could otherwise damage them.
A1AT levels help assess whether the body is producing enough of this protective protein. A shortage is linked to an inherited condition that can affect the lungs and sometimes the liver. Testing can help explain certain lung or liver findings and identify people who carry this genetic pattern.
A higher A1AT can occur simply because it rises during inflammation or infection anywhere in the body, since it is one of the proteins that increases as part of that response. On its own, a high level is usually not the main focus and is interpreted in light of what else is going on.
A lower A1AT can suggest an inherited deficiency that may warrant further evaluation, since it can affect lung and liver health over time. Low results are typically followed up with additional testing to clarify.
Your result is compared to your lab's reference range, and genetic or specialized testing is sometimes added for clarity. Your clinician can interpret what your level means and whether any follow-up is helpful.
Sources
Educational context only, not medical advice or a diagnosis. Reference ranges vary by lab, age and sex; always discuss your results with a clinician.