Quantitative nephelometry test

  • Definition
    • Quantitative nephelometry is a lab test to quickly and accurately measure levels of certain proteins called immunoglobulins in the blood. Immunoglobulins are antibodies that help fight infection.

      This test specifically measures the immunoglobulins IgM, IgG, and IgA.

  • Alternative Names
    • Quantitative immunoglobulins

  • How the Test is Performed
  • How to Prepare for the Test
    • You may be asked not to eat or drink anything for 4 hours before the test.

  • How the Test will Feel
    • When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging. Afterward, there may be some throbbing or slight bruising. This soon goes away.

  • Why the Test is Performed
    • The test provides a rapid and accurate measurement of the amounts of the immunoglobulins IgM, IgG, and IgA.

  • Normal Results
    • Normal results for the 3 immunoglobulins are:

      • IgG: 560 to 1800 mg/dL
      • IgM: 45 to 250 mg/dL
      • IgA: 100 to 400 mg/dL

      The examples above show the common measurements for these test results. Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results. Some labs use different measurements or test different samples.

  • What Abnormal Results Mean
    • An increased level of IgG may be due to:

      Decreased levels of IgG may be due to:

      Increased levels of IgM may be due to:

      Decreased levels of IgM may be due to:

      • Agammaglobulinemia (very rare)
      • Leukemia
      • Multiple myeloma

      Increased levels of IgA may be due to:

      • Chronic infections, especially of the gastrointestinal tract
      • Inflammatory bowel disease, such as Crohn disease
      • Multiple myeloma

      Decreased levels of IgA may be due to:

      • Agammaglobulinemia (very rare)
      • Hereditary IgA deficiency
      • Multiple myeloma
      • Gut disease that leads to protein loss

      Other tests are needed to confirm or diagnose any of the conditions above.

  • Risks
    • There is very little risk involved with having your blood taken. Veins and arteries vary in size from one person to another and from one side of the body to the other. Taking blood from some people may be more difficult than from others.

      Other risks associated with having blood drawn are slight but may include:

      • Excessive bleeding
      • Fainting or feeling lightheaded
      • Hematoma (blood accumulating under the skin)
      • Infection (a slight risk any time the skin is broken)
  • References
    • Abraham R, Barnidge DR, Lanza IR. Assessment of proteins of the immune system. In: Rich RR, Fleisher TA, Shearer WT, Schroeder HW, Frew AJ, Weyand CM, eds. Clinical Immunology: Principles and Practice. 4th ed. Philadelphia, PA: Elsevier; 2016:chap 93.

      McPherson RA. Specific proteins. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 23rd ed. St Louis, MO: Elsevier; 2017:chap 19.