A lupus diagnosis is difficult because the signs and symptoms may considerably vary from person to person. Also, the signs and symptoms vary over time and overlap as well with those of many other disorders. There is no one particular test for a lupus diagnosis. A combination of blood and urine tests, constant monitoring of symptoms and signs along with physical examination findings can lead to a proper lupus diagnosis.

Laboratory tests
Blood and urine test for lupus diagnosis may include the following tests:

• Complete blood count: This test is meant for measuring the number of red blood cells, white blood cells, and platelets along with the amount of hemoglobin, which is a protein in the red blood cells. In case the results indicate that you have anemia, know that it commonly occurs in lupus. Also, a low platelet or white blood cell count may occur as well in lupus.
• Erythrocyte sedimentation rate: This blood test determines the rate at which red blood cells settle to the bottom of a tube in an hour. A faster rate compared to the normal rate may indicate a systemic disease, such as lupus. The sedimentation rate is not specific for a particular disease. It may be elevated if you have lupus, inflammation, another inflammatory condition, or even cancer.
• Kidney and liver assessments: How well your kidneys and liver are functioning can be assessed by blood tests, as lupus can affect these organs as well.
• Urinalysis: If an examination of a sample of your urine indicates an increased level of protein or red blood cells in the urine, there may be chances that lupus has affected the kidneys.
• Antinuclear antibody (ANA) test: A positive test for the presence of these antibodies which are produced by your immune system is an indication of a stimulated immune system. While most people with the condition of lupus have a positive ANA test, it is not necessary that anyone with a positive ANA will have lupus. If the tests are positive for ANA, your doctor may advise you further to take some specific antibody testing.

Imaging tests
If your doctor suspects that your lupus condition is affecting your lungs or heart, they may suggest the following imaging tests:

• Chest X-ray: If there is an image of your chest revealing abnormal shadows, it may be suggested that your lungs have fluids or inflammation.
• Echocardiogram:To produce real-time images of your beating heart, this test uses sound waves. This test can check for problems with your valves and other portions of your heart.

Biopsy
Lupus may harm your kidney in several ways. This may affect the kind of treatments you may receive depending on the type of damage that occurs. In a few cases, it is essential to test a small sample of the kidney tissue to determine what the best treatment might be based on the condition.The sample can be obtained through a small incision or with a needle. Also, a skin biopsy is sometimes performed as well to confirm a lupus diagnosis affecting the skin.

Thus, there being no single test for lupus diagnosis, it is essential to perform the above tests to know which organs of your body are affected by this disease.