Quantitative nephelometry test

定义

Quantitative nephelometry is a lab test to quickly and accurately measure levels of certain proteins called immunoglobulins in the blood. 免疫球蛋白是 抗体 that help fight infection.

This test specifically measures the immunoglobulins IgM, 免疫球蛋白, 与IgA.

选择的名字

Quantitative immunoglobulins

How the Test is Performed

A 需要血液样本.

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. 这很快就会消失.

Why the Test is Performed

The test provides a rapid and accurate measurement of the amounts of the immunoglobulins IgM, 免疫球蛋白, 与IgA.

正常的结果

Normal results for the three immunoglobulins are:

• 免疫球蛋白: 650 to 1600 milligrams per deciliter (mg/dL), or 6.5 to 16.0 grams per liter (g/L)
• IgM: 54 to 300 mg/dL, or 540 to 3000 mg/L
• IgA: 40 to 350 mg/dL, or 400 to 3500 mg/L

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 免疫球蛋白 may be due to:

• 慢性 infection or inflammation
• Hyperimmunization (higher than normal number of specific 抗体)
• 免疫球蛋白 多发性骨髓瘤 (a type of blood cancer)
• 肝脏疾病
• 类风湿性关节炎

Decreased levels of 免疫球蛋白 may be due to:

• Agammaglobulinemia (very low levels of immunoglobulins, a very rare disorder)
• 白血病 (血癌)
• 多发性骨髓瘤 (骨髓癌)
• 子痫前期 (high blood pressure during pregnancy)
• Treatment with certain chemotherapy drugs

Increased levels of IgM may be due to:

• 单核细胞增多症
• Lymphoma (cancer of the lymph tissue)
• Waldenström macroglobulinemia (cancer of the white blood cells)
• 多发性骨髓瘤
• 类风湿性关节炎
• 感染

Decreased levels of IgM may be due to:

• Agammaglobulinemia (very rare)
• 白血病
• 多发性骨髓瘤

Increased levels of IgA may be due to:

• 慢性 infections, especially of the gastrointestinal tract
• Inflammatory bowel disease, such as 克罗恩病
• 多发性骨髓瘤

Decreased levels of IgA may be due to:

• Agammaglobulinemia (very rare)
• Hereditary IgA deficiency
• 多发性骨髓瘤
• Gut disease that leads to protein loss

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

风险

There is 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:

• 大出血
• Fainting or feeling lightheaded
• Multiple punctures to locate veins
• Hematoma (blood accumulating under the skin)
• 感染 (a slight risk any time the skin is broken)

参考文献

亚伯拉罕RS. Assessment of functional immune responses in lymphocytes. In: Rich RR, Fleisher TA, Shearer WT, Schroeder HW, Few AJ, Weyand CM, eds. Clinical Immunology: Principles and Practice. 5日艾德. Philadelphia, PA: Elsevier; 2019:chap 93.

麦克弗森拉. 特定的蛋白质. In: 麦克弗森拉, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24日艾德. Philadelphia, PA: Elsevier; 2022:chap 20.