Raji Cell Assay

This assay, which is performed to detect the presence of circulating immune complexes, studies the Raji lymphoblastoid cell line. Identifying these cells, which have receptors for immunoglobulin G complement, helps to evaluate autoimmune disease.

Purpose

• To detect circulating immune complexes
• To aid the study of autoimmune disease

Patient preparation

• As appropriate, explain to the patient the purpose of the test.
• Tell him that the test requires a blood sample and who will perform the venipuncture and when.
• Reassure him that although he may experience transient discomfort from the needle puncture and the tourniquet, collecting the sample takes less than 3 minutes.

Procedure and posttest care

• Perform a venipuncture, and collect a sample in a red-top, red-marble-top, or green-top tube. Place the sample on ice and send it to the laboratory for assay.
• If a hematoma develops at the venipuncture site, apply warm soaks.

Precautions

• Handle the sample gently to prevent hemolysis.

Reference values

Normal value is less than 13 mg AHG (antihemophilic globulin) Eq/ml.

Abnormal findings

A positive Raji cell assay can detect immune complexes, including those found in viral, microbial, and parasitic infections; metastasis; autoimmune disorders; and drug reactions. This test may also detect immune complexes associated with celiac disease, cirrhosis, Crohn's disease, cryoglobulinemia, dermatitis herpetiformis, sickle cell anemia, and ulcerative colitis.

Interfering factors

• Hemolysis due to rough handling of the sample
• Recent injection of radioactive contrast medium
• Failure to place the sample on ice