Monoclonal immunoglobulins consist of heavy and light chains. IFE identifies presence or absence of a monoclonal protein and determines its heavy-chain and light-chain types.

This test measures immune status and competence by identifying monoclonal and particle protein band immunoglobulins involved in the immune response. IFE is a follow-up test performed when monoclonal spike is observed on SPEP or when a monoclonal gammopathy is suspected on the basis of the patient’s immunoglobulin concentrations.

• No abnormality present

1. Collect a 7-mL blood serum sample in a red-topped tube or a 24-hour urine specimen. Observe standard precautions. Submit 25 mL from a 24-hour urine collection if a urine IFE is to be run simultaneously.

2. If the IFE is a follow-up to a paraprotein being demonstrated by PEP (see Protein Electrophoresis [PEP], Serum and Urine), the same specimen (blood, urine, or both) used for the electrophoresis can be used for this procedure as well.

3. In IFE, high-resolution electrophoresis produces stained bands. By comparing the location of the stained immunofixed band with a band in the same location in the SPEP reference pattern, a particular protein band can be identified.

1. Monoclonal protein in the serum or urine suggests a neoplastic process; a polyclonal increase in immunoglobulins is seen in chronic liver disease, connective tissue disease, and infection.

2. With multiple myeloma, 99% of patients have a monoclonal protein in the serum or urine. Waldenström macroglobulinemia is characterized by the presence of a serum monoclonal IgM protein in all cases.

3. A monoclonal light chain (K or Bence Jones protein) is found in the urine of about 75% of patients with multiple myeloma. Approximately 75% of patients with Waldenström macroglobulinemia have a monoclonal light chain in the urine. Heavy-chain fragments as well as free light chains may be seen in the urine of patients with multiple myeloma or amyloidosis.

Pretest Patient Care

1. Explain test purpose and specimen collection procedure.

2. Submit the same specimen for the SPEP if a blood sample is needed. If the test is to be performed separately, another 7-mL blood sample collected in a red-topped tube is required. Note patient’s age; this procedure is seldom indicated in patients younger than 30 years because monoclonal proteins are rarely identified in this age group.

3. A 24-hour urine specimen is preferred. Provide instructions and a 24-hour collection container (see Chapter 3 for protocols).

4. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.