LE (lupus erythematosus) cell test measures the presence of a special cell found mostly in patients with systemic lupus erythematosus.

Blood is drawn from a vein, usually from the inside of the elbow or the back of the hand. The puncture site is cleaned with antiseptic, and a band or blood pressure cuff is placed around the upper arm to cause the veins below the band to swell.

A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. During the procedure, the band is removed to restore circulation. Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.

In infants and young children:

The area is cleaned with antiseptic and punctured with a sharp needle or a lancet. The blood may be collected in a pipette (small glass tube), on a slide, onto a test strip, or into a small container. A bandage may be applied to the puncture site if there is any continued bleeding.

When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.

The LE cell test is used primarily to diagnose systemic lupus erythematosus (SLE).

No presence of LE cells is normal.

The LE cell test is used primarily to diagnose systemic lupus erythematosus (SLE). About 50 to 75% of patients with SLE have a positive test. Some patients with rheumatoid arthritis, scleroderma, and drug sensitivities (see drug-induced lupus erythematosus) also exhibit a positive LE cell test.

• Excessive bleeding
• Fainting or feeling light-headed
• Hematoma (blood accumulating under the skin)
• Infection (a slight risk any time the skin is broken)
• Multiple punctures to locate veins

The LE cell test is now only rarely performed and mostly has historic significance.

Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.