Lab Tests to Diagnose Systemic Lupus Erythematosus (Lupus)
Systemic lupus erythematosus (lupus) is a chronic autoimmune disease that can affect various parts of the body, including the skin, joints, kidneys, heart, and central nervous system. It is more commonly diagnosed in women and can have diverse symptoms and disease onset.
Diagnosing lupus can be challenging because its symptoms can come and go and mimic those of other disorders or diseases. Currently, there is no single test to definitively diagnose lupus. However, doctors use a combination of medical history, physical examination, and laboratory tests to help make a diagnosis. Here are some of the lab tests commonly used:
- Antinuclear antibodies (ANA): This is a sensitive test for lupus. Almost all people with lupus will have a positive ANA result. However, it's important to note that having a positive ANA does not necessarily mean you have lupus since healthy individuals can also test positive.
- Antiphospholipid antibodies: These antibodies are tested when an individual has a positive ANA result. They can help determine if someone has lupus.
- Anti-Smith antibodies: These antibodies are also tested when an individual has a positive ANA result. They are specific to lupus and can further support the diagnosis.
- Anti-double-strand DNA antibodies: These antibodies are another test performed when an individual has a positive ANA result. They are highly specific to lupus and can provide additional evidence for the diagnosis.
In addition to these specific antibody tests, other laboratory tests may be done to check for certain abnormalities associated with lupus:
- Complete blood counts: These tests check for low platelet counts, low red blood cell counts, and low white blood cell levels, which can occur in individuals with lupus.
- Metabolic panel: This test looks for changes in kidney function, as lupus can affect the kidneys.
- Urine samples: Taking urine samples helps check for abnormal levels of protein in the urine, which can be a sign of kidney involvement in lupus.
In some cases, if there is suspicion of kidney involvement or skin problems related to lupus, a biopsy may be performed. During a biopsy, a small sample of skin or kidney tissue is taken and examined under a microscope to look for any abnormalities associated with lupus.
It's important to remember that diagnosing lupus requires a comprehensive evaluation by a healthcare professional who will consider multiple factors including symptoms, medical history, physical examination findings, and laboratory results. If you suspect you may have lupus or have concerns about your health, it's essential to consult with your doctor who can guide you through the diagnostic process and develop an appropriate treatment plan tailored to your needs.