A complement test uses a blood sample to detect a group of proteins
that help the body attack foreign substances.
When there are a lot of foreign substances in the body, such as
bacteria or viruses, a low level of complement means the body is trying to get
rid of the foreign substances. If the body is attacking its own tissues instead
of foreign substances (as in
autoimmune diseases such as
lupus), a low level of complement may mean that the
body is attacking and damaging tissues such as the kidneys.
The complement test can be repeated at regular intervals. This helps monitor the progress of the disease.
ByHealthwise Staff Primary Medical ReviewerAnne C. Poinier, MD - Internal Medicine Brian D. O'Brien, MD - Internal Medicine Martin J. Gabica, MD - Family Medicine Kathleen Romito, MD - Family Medicine Specialist Medical ReviewerNancy Ann Shadick, MD, MPH - Internal Medicine, Rheumatology